Which fault codes are you seeing now? If you're not sure what they mean, you can look them up on the Ross Tech Wiki which will provide specific information including possible symptoms, causes and solutions. (Link here).

IMHO, and I think others will agree, catch cans are a waste of money and just become and unnecessary maintenance item. For anyone in colder climates where it could freeze, it's one more item to worry about.

If the PCV you bought before was some cheap no-name eBay version, then get one from Audi (or at least a known brand like Febi or Vaico) so you know you have a genuine part. As to the battery, is it the correct battery for your TT?

Since you mentioned the HPFP, when was the last time you replaced the cam follower? (Link here)

Lastly, can you verify which engine code you have. By that I mean there are two versions of the 2.0 engine; (1) EA113 or (2) EA888. Check your VIN sticker to verify which one you have. (Link here) And which transmission do you have; stick or DSG?

 

Can you post the scan from the engine module (if not a full scan)? You need to trouble shoot each code from scratch really. Just because you had a problem before that "was the PCV" doesn't mean every time you see the same or similar code, it's automatically going to be the PCV. Underboost code can be caused by quite a few things, and again you should never assume that "what it was last time" must/necessarily be what is wrong this time. I'm also not sure if what you are saying is you had the underboost code before, replaced the PCV but never cleared the code and it's an "old code", or whether you're having underboost codes again and are merely assuming it's the PCV again. Hence why a full scan posting would help others to understand what is going on.

 

I uploaded my scans from my obd11. Mind you I have no cats, just a catless cts turbo downpipe so the p0420 code has been there. The Pcv I bought before was from my local auto parts store so yeah not the best. Also I know my profile picture may throw you off with the snow but I actually live in Florida so we don’t get much cold. I was getting told a catch can was the way to go but now that I do more research on it I don’t know what to think on it. Even though this could have been the start of it all I don’t see it keeping me from having spark. Can follower has never been replaced, I might consider checking in on that next. I will check for the engine code when I get off of work today. I did get the under boost code before the car stopped getting spark but that didn’t make me assume my Pcv went bad again, I was getting the same exact symptoms as in my oil cap and dipstick having a strong suction when vehicle on and also the motor would almost shutter when I took the oil cap off. Those symptoms made me question my Pcv being bad again as well as oil build up around the oil cap and Pcv valve. Thank yall so much for your input I really appreciate it, I’m not a mechanic by any means, I am a 21 year old who has never had to take his car to the shop and I won’t start today XD

Moderator note - I deleted your attachment as you probably don't want your VIN on a public forum. You'll notice I changed it for this post -

OBDeleven vehicle history log

Date: 2025-09-30 18:58

    VIN: TRUBF38J6XXXXXXXX
    Car: Audi TT
    Year: 2008
    Body type: Coupe
    Mileage: 374670 KM

---------------------------------------------------------------
Fault
    Control unit: 01 Engine
    Active faults: 5
    Inactive faults: 0
    System description: 2.0l R4/4V TFSI
    Software number: 8J0907115B
    Software version: 0020
    Hardware number: 8J0907115
    Serial number: AUX7Z0H3FNB0OO
    Faults:
        P0420 - Catalyst System,Bank1 Efficiency Below Threshold Lower limit not reached
            Intermittent
                Priority:  2
                Frequency counter:  1
                Driving cycle: 255
                Mileage: 363661 km
                Date: 2025-08-02 13:31:12
        P0299 - Turbo/Super Charger Underboost Lower limit not reached
            Intermittent
                Priority:  2
                Frequency counter:  1
                Driving cycle: 255
                Mileage: 364755 km
                Date: 2025-08-06 09:15:41
        P0016 - Crankshaft Position-Camshaft Position Correlation Bank 1 Sensor A Implausible signal
            Intermittent
                Priority:  2
                Frequency counter:  1
                Driving cycle: 255
                Mileage: 373955 km
                Date: 2025-09-12 19:01:32
        P0303 - Cyl.3 Misfire Detected Implausible signal
            Intermittent
                Priority:  2
                Frequency counter:  1
                Driving cycle: 255
                Mileage: 374046 km
                Date: 2025-09-13 18:00:15
        P1602 - Power supply terminal 30 Voltage too low Lower limit not reached
            Intermittent
                Priority:  2
                Frequency counter:  1
                Driving cycle: 255


    Mileage: 374670 km
    Date: 2025-09-25 17:40

---------------------------------------------------------------
Fault
    Control unit: 02 Transmission
    Active faults: 0
    Inactive faults: 0
    System description: GSG DSG         082
    Software number: 02E300050J
    Software version: 1406
    Hardware number: 02E927770AD
    Hardware version: C30
    Serial number: 00001004020039
    Faults:
        No trouble codes found

    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 03 Brakes
    Active faults: 1
    Inactive faults: 0
    System description: ESP MK60E1
    Software number: 8J0614517
    Software version: 0130
    Hardware number: 8J0614517
    Faults:
        01826 - Steering angle sensor, voltage supply terminal 30
            static
                Priority:  2
                Frequency counter:  1
                Driving cycle: 163
                Mileage: 374670 km


    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 08 Air Conditioning
    Active faults: 1
    Inactive faults: 0
    System description: J255  Klima 1 Zone
    Software number: 8J0820043AJ
    Software version: 0080
    Hardware number: 8J0820043AJ
    Serial number: 00000001085096
    Faults:
        01206 - Signal for duration of -Ignition OFF- Implausible signal
            static
                Priority:  7
                Frequency counter:  1
                Driving cycle: 163
                Mileage: 374670 km
                Date: 2025-09-15 00:00:31


    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 09 Central Electrics
    Active faults: 1
    Inactive faults: 0
    System description: Bordnetz-SG     H54
    Software number: 8P0907279K
    Software version: 2501
    Hardware number: 8P0907279K
    Hardware version: 063
    Serial number: 00000008332776
    Faults:
        01493 - Left front turn signal bulb Electrical error in circuit
            static
                Priority:  2
                Frequency counter:  2
                Driving cycle: 163
                Mileage: 373122 km
                Date: 2025-09-09 19:10:00


    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 0F Digital Radio
    Active faults: 1
    Inactive faults: 0
    System description: SDAR SIRIUS     H07
    Software number: 8E0035593M
    Software version: 0150
    Hardware number: 8E0035593M
    Serial number: AUZ4Z7H0294931
    Faults:
        00003 - Control module Faulty
            Intermittent
                Priority:  5
                Frequency counter:  6
                Driving cycle: 117
                Mileage: 365446 km
                Date: 2025-08-07 22:10:28


    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 15 Airbag
    Active faults: 0
    Inactive faults: 0
    System description: -E Airbag 9.43  H02
    Software number: 8J0959655
    Software version: 0020
    Hardware number: 8J0959655
    Serial number: 0036K002MBR5
    Faults:
        No trouble codes found

    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 16 Steering Column
    Active faults: 1
    Inactive faults: 0
    System description: J0527           H36
    Software number: 8P0953549F
    Software version: 0070
    Hardware number: 8P0953549F
    Faults:
        01426 - Control unit in steering wheel No signal/communication
            Intermittent


    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 17 Dashboard
    Active faults: 1
    Inactive faults: 0
    System description: KOMBIINSTR. VDO H23
    Software number: 8J0920990E
    Software version: 0150
    Hardware number: 8J0920990E
    Serial number: 2243H003102970
    Faults:
        00562 - Oil Level Thermal Sensor Implausible signal
            Intermittent
                Priority:  6
                Frequency counter: 54
                Driving cycle: 203
                Mileage: 364374 km
                Date: 2025-08-04 19:16:23


    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 19 Gateway
    Active faults: 0
    Inactive faults: 0
    System description: J533__Gateway   H16
    Software number: 1K0907530P
    Software version: 0192
    Hardware number: 1K0907951
    Serial number: 2500K083298387
    Faults:
        No trouble codes found

    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 25 Immobilizer
    Active faults: 0
    Inactive faults: 0
    System description: KOMBIINSTR. VDO H23
    Software number: 8J0920990E
    Software version: 0150
    Hardware number: 8J0920990E
    Serial number: AUX7Z0H3FNB0OO
    Faults:
        No trouble codes found

    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 37 Navigation
    Active faults: 0
    Inactive faults: 0
    System description: RNS-E US        H15
    Software number: 8J0035192P
    Software version: 0260
    Hardware number: 8J0035192P
    Serial number: AUZBZ7H4501936
    Faults:
        No trouble codes found

    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 42 Driver Door
    Active faults: 2
    Inactive faults: 0
    System description: Tuer-SG         H02
    Software number: 8J8959801E
    Software version: 0060
    Hardware number: 8J8959801E
    Faults:
        00912 - Front left window lift switch Implausible signal
            Intermittent
        00109 - Mirror turn signal bulb, driver side Electrical error in circuit
            static


    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 44 Steering Assistance
    Active faults: 1
    Inactive faults: 0
    System description: EPS_ZFLS Kl.157 H08
    Software number: 8J1909143C
    Software version: 1903
    Faults:
        00778 - Steering angle sensor
            static


    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 46 Comfort System
    Active faults: 3
    Inactive faults: 0
    System description: KSG          H11
    Software number: 8J0959433C
    Software version: 0080
    Faults:
        01134 - Alarm horn No signal/communication
            Intermittent
        03132 - Rear spoiler stop switch Implausible signal
            Intermittent
        01134 - Alarm horn
            static


    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 47 Sound System
    Active faults: 0
    Inactive faults: 0
    System description: J525 Amp High   H04
    Software number: 8J0035223D
    Software version: 0150
    Hardware number: 8J0035223D
    Serial number: 00000000007182
    Faults:
        No trouble codes found

    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 52 Passenger Door
    Active faults: 2
    Inactive faults: 0
    System description: Tuer-SG         H02
    Software number: 8J8959802E
    Software version: 0060
    Hardware number: 8J8959802E
    Faults:
        01553 - Front passenger door central locking LOCK motor Electrical error in circuit
            Intermittent
        00929 - Lock unit for central locking Frt. pass. side Implausible signal
            Intermittent


    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 55 Headlight Regulation
    Active faults: 0
    Inactive faults: 0
    System description: AFS 1           H01
    Software number: 4L0910357
    Software version: 0040
    Hardware number: 4L0907357
    Faults:
        No trouble codes found

    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 56 Radio
    Active faults: 0
    Inactive faults: 0
    System description: RNS-E US        H15
    Software number: 8J0035192P
    Software version: 0260
    Hardware number: 8J0035192P
    Serial number: AUZBZ7H4501936
    Faults:
        No trouble codes found

    Mileage: 374670 km
    Date: 2025-09-25 17:41

---------------------------------------------------------------
Fault
    Control unit: 65 Tire Pressure
    Active faults: 1
    Inactive faults: 0
    System description: J502-RDK        H03
    Software number: 8J0907273A
    Software version: 0370
    Hardware number: 8J0907273A
    Serial number: 12956780526569
    Faults:
        02214 - Tire pressure warning
            static
                Priority:  1
                Frequency counter:  1
                Driving cycle: 101
                Mileage: 368464 km
                Date: 2025-08-20 06:43:16


    Mileage: 374670 km
    Date: 2025-09-25 17:41

 

You can always look up the fault codes on the Ross Tech Wiki. Here's how -

https://www.ttforum.co.uk/posts/9635292/

Be sure to read through the entire wiki page and pay attention to the Special Notes as they are often model/engine specific.

 

I'm noticing a few things right away here. One is this vehicle is pretty high miles. Nothing wrong with that but yeah I thought I had a bit at 250k kms, you got another 100k+ heh. But at this mileage if a lot of preventative maintenance items haven't been done in the past--not just talking bout VAG's woefully inadequate schedule, I mean other things that long-term owners would want to be doing over and above that stuff--well that's when more problems are going to rear their heads/multiply.

Secondly was the catalyst code, since it's the first one but is explained here...

I uploaded my scans from my obd11. Mind you I have no cats, just a catless cts turbo downpipe so the p0420 code has been there.

You really ought to have a Stage 2 tune on this, not just for the powder but the fact the light would be off. The problem with the light on all the time is you don't know when other things start happening, when they happen, because the light is on all the time anyway. Though note that in the US a lot of tuning companies have stopped removing emissions related codes because of EPA threats/mandates, unfortunately.

Anyway can you clarify one thing here. Is this an EA888 engine or an EA113? The EA888 will have a metal/can oil filter on top while the EA113 the oil filter is a cartridge on the bottom in a plastic housing. On an 08 TT I assume it's an EA113 but the TT is weird and the transistion between the two is a lot more murky than other VAG models.

The Pcv I bought before was from my local auto parts store so yeah not the best. Also I know my profile picture may throw you off with the snow but I actually live in Florida so we don’t get much cold.

A good note to be sure...I take it with those kind of miles on the car you must drive it a lot of places, lol.

I was getting told a catch can was the way to go but now that I do more research on it I don’t know what to think on it.

FTLOG don't listen to these people! I don't want to get too far OT on a rant on this but these people are clowns that know nothing about cars. If you "needed a catch can, bro" for the car to run right, as these know-nothings like to preach...how would this car have made it to like 225k miles without having had one? It's beyond maddening people that have no idea about anything are still going on with the "get a catchcan bro" stupidness, as some catch-all to fix cars. I digress...

Even though this could have been the start of it all I don’t see it keeping me from having spark.

Another question...how have you determined that you're "not getting spark"? I mean are you sure that's the issue here? You aren't getting a P130A so doesn't seem like it's in limp mode...at least not yet.

Can follower has never been replaced, I might consider checking in on that next.

Sounds like it indeed is an EA113 then. But never been replaced...on a 2008 vehicle with over 200k miles on it??? That's not sounding too good TBH. Are you sure it wasn't replaced by a PO...presuming you aren't the original owner? That's crazy mileage to be on the original follower.

I will check for the engine code when I get off of work today.

You're not driving the car around still though, correct?

I did get the under boost code before the car stopped getting spark but that didn’t make me assume my Pcv went bad again, I was getting the same exact symptoms as in my oil cap and dipstick having a strong suction when vehicle on and also the motor would almost shutter when I took the oil cap off. Those symptoms made me question my Pcv being bad again as well as oil build up around the oil cap and Pcv valve. Thank yall so much for your input I really appreciate it, I’m not a mechanic by any means, I am a 21 year old who has never had to take his car to the shop and I won’t start today XD

Have you done a compression test on the engine yet? I think that would probably be your next step...well after checking that potentially-original cam follower.

 

Lmao yes it does have very high mileage I got the car at 175k miles and I drive it about 150 miles a day. I hate that I have to drive it that much but it is what it is, I try to keep up with as much maintenance as possible but I had no idea that the cam follower had to be replaced every 10-15k miles that’s new for me. That being said I pulled my hpfp and it did not look so good I will post a picture.

I do have the EA113 engine. Would you think an oem like Pcv back on there or should I just look into adding my velt block off plate with no catch can ?

No sadly I haven’t been able to even drive it since it won’t crank. I’m pretty positive the cam follower could have been the cause of my problems. Before the car completely shut down I was having loss of power at higher rpm’s , jerkiness when accelerating and the car kept going into limp mode which I assume is why it stalled/no start.

sorry I haven’t got back to you but I was getting somebody to start it while I sprayed starter fluid and I had a loud pop which is good because that tells me I have spark. When I get home today I will be pulling the cam follower and inspecting the cam lobe. I can only assume that this may have damaged my hpfp as well.

I’ve been looking into getting the tune I have only been catless for about 2 months. I think integrated engineering has some decent tunes so I might consider that.

 

Forget about the PCV block-off plate, they cause more problems than they solve.
A new PCV valve for an EA113 is cheap. Re-install using an OE part obtained from a reputable source (not eBay / Amazon).

Forget about a Stage 2 tune. Wouldn't recommend it for a high-mileage car, a FWD or an otherwise stock EA113. Would have been better to have left your cats alone and tune to Stage1.

Too late now but you've learned why you don't continue to drive when your car clearly had issues.
Get your fueling in order first. Hope your HPFP and / or camshaft isn't damaged as that will be expensive to repair. Also hope the camshaft / crankshaft correlation error doesn't imply jumped timing as that could be catastrophic...

 

Lmao yes it does have very high mileage I got the car at 175k miles and I drive it about 150 miles a day. I hate that I have to drive it that much but it is what it is,

Nah I mean if you gotta drive it, drive it. Drive something enjoyable no need to get a minivan or a Civic or something to drive a lot of miles...unless you really want that lol.

I try to keep up with as much maintenance as possible but I had no idea that the cam follower had to be replaced every 10-15k miles that’s new for me. That being said I pulled my hpfp and it did not look so good I will post a picture.

10-15k miles is probably excessive but yeah you really do need to know about this issue with these engines, which you do now but maybe a bit late. I've gone probably 50k kms (so around 30k miles) on the follower I put in when I got the car, and it was still fine at last check earlier this year. So you can probably go a lot longer on a follower than 15k miles esp. if you have the revised cam (though we don't know if yours does).

I do have the EA113 engine. Would you think an oem like Pcv back on there or should I just look into adding my velt block off plate with no catch can ?

I would say put the OE PCV back on, full stop. Meaning not an aftermarket valve but an OE one. It's expensive but probably your best bet if you plan on keeping the car a while. The originals are made by Mann+Hummel but I don't think they sell these in the aftermarket (like they do filters for example). So I think the best non-VAG part might be the Hengst versions which I think are about half the price of the VAG ones--you do need to figure out what version PCV is correct for your car though as there are two different types.

No sadly I haven’t been able to even drive it since it won’t crank. I’m pretty positive the cam follower could have been the cause of my problems. Before the car completely shut down I was having loss of power at higher rpm’s , jerkiness when accelerating and the car kept going into limp mode which I assume is why it stalled/no start.

So the picture of the follower you took is actually the wrong side, heh. You need to pull the follower out--kind of like a thimble it's sitting in there--and post a picture of the other side and of the camshaft lobe. On the plus side the follower is not worn through, so that's a good sign at least.

sorry I haven’t got back to you but I was getting somebody to start it while I sprayed starter fluid and I had a loud pop which is good because that tells me I have spark. When I get home today I will be pulling the cam follower and inspecting the cam lobe. I can only assume that this may have damaged my hpfp as well.

Indeed so the car does have spark though we don't know if on all cylinders. I assume you have tried swapping the #3 coil with another one? But yeah don't go back to that yet, let's see what the follower, HPFP, and cam lobe look like.

If those are okay (it's looking like they could be but just one step away from seeing, lol), then I'd suggest to move on to a compression (and/or leakdown) test next...

I’ve been looking into getting the tune I have only been catless for about 2 months. I think integrated engineering has some decent tunes so I might consider that.

Unfortunately getting an IE tune now won't help you with the O2 sensor code See my note here:

https://www.ttforum.co.uk/threads/tts-stage-2-whos-done-it-advice-please.1878651/page-2?post_id=9729039#post-9729039

Though most people report you can get away with most any Stage 2 tune and catless/HF aftermarket cat, just by using an O2 sensor spacer. YMMV with that, but definitely forget about modding for now as you have some issues on your hands.

Forget about a Stage 2 tune. Wouldn't recommend it for a high-mileage car, a FWD or an otherwise stock EA113. Would have been better to have left your cats alone and tune to Stage1.

I agree on the second part, not so much the first, but I was more going on a "well you're in this boat now..." kind of thing. Would have been much better to keep the stock cats/DP in place, presuming they were still in good condition. In fact if OP somehow still has the DP then might be a good idea to just put it back on...but in any event more pressing to figure out/solve what's wrong with the car now.

 

Honesty the main reason I swapped my dp out was because my oem one broke off lol. I got the car for cheap , still doesn’t give me a reason to not take care of it. I really love this car and will always be a Audi fan boy XD

I pulled the cam follower out and it definitely has some wear on it, I will post pictures of that and the hpfp. I know for sure I have to replace the cam follower no doubt but the fuel pump ? I mean I’m sure it took some damage. The cam lobe looks nice and shiny as it should so that’s a relief. Of course I’m going to order new plugs,coil packs, and cam follower but I want to make sure I don’t need to go ahead and replace the hpfp.

I’m crossing my fingers and toes that this is the problem for my no start condition although it’s a very weird thing to make the car just not start. Knock on wood but if this ain’t my main problem I will definitely look in to doing a compression and leak down test.

I’ve been looking at the oem alike Pcv valve and there not too pricey I did pay 75$ usd for the velt pcv Plate.

thanks again for your help

 

Honesty the main reason I swapped my dp out was because my oem one broke off lol. I got the car for cheap , still doesn’t give me a reason to not take care of it. I really love this car and will always be a Audi fan boy XD

Well the new OEM pipe is going to be crazy expensive I'm sure and in the US it's very difficult to get a used one since junkyards cannot sell them (it's illegal). You could find one for private sale I believe, but that's about it. So I can kind of understand not replacing with an original; though if it were me I'd have replaced it with a catted pipe, not a "test" one. But anyway...

I pulled the cam follower out and it definitely has some wear on it,

So that follower is now 100% worn out. However it has not reached the point where it would have caused damage. It can be at that state and caused damage but you'd see some "concavity" in the top if that were the case--doesn't look like it in the pictures but tough to tell.

There is a TSB that discusses condition of parts and when damage has occurred but TBH the pictures in the TSB are not even good lol:

https://static.nhtsa.gov/odi/tsbs/2014/MC-10124300-9999.pdf

Otherwise as long as it's flat still, the follower has a black coating on it called "DLC" (diamond-like coating) and when the coating just starts to wear off, that's when it's "time to replace it". Yours has completely worn off but thankfully it has not really worn into the follower yet. But this is a "change ASAP" item now. You basically caught it just in time it seems.

You can get an OE INA follower much cheaper than buying one at the stealer; you can get a complete kit with new bolts and o-ring for less than $40 here:

https://www.fcpeuro.com/products/audi-vw-fuel-pump-cam-follower-kit-ina-06d109309ckt

The sell the follower alone for $18 but TBH you may as well just get the bolts and o-ring to replace one time. The only difference between this follower and the one you'd buy at a stealer is this one is US made while the one from dealer will probably be European made. They are both made by the same company though--INA.

I will post pictures of that and the hpfp. I know for sure I have to replace the cam follower no doubt but the fuel pump ? I mean I’m sure it took some damage. The cam lobe looks nice and shiny as it should so that’s a relief. Of course I’m going to order new plugs,coil packs, and cam follower but I want to make sure I don’t need to go ahead and replace the hpfp.

Visually everything looks fine here, yeah. Good news there. However note the HPFP can fail in a few different ways so just because the piston is ok doesn't mean it hasn't failed in another way. But, your codes are not indicative of a fuel pump issue either really. The misfire could be fueling-related but there's no codes indicating issues with high pressure fuel. But, you do need to change that follower!

What the P0016 could be is the cam chain/tensioner--the guide is known to crack/break causing issues here. You may have multiple issues here. The misfire might be related to the P0016 issue but it may not be. Typically speaking if that tensioner becomes an issue the engine doesn't jump time but you would need to pull the cover and inspect it. It can jump time but usually it doesn't. Had you been hearing a rattling that continued after the engine has started more than a few seconds? The chain is "allowed" to rattle when the engine is started because the tensioner needs to fill with oil; but if the rattling continues more than 2-3 seconds, it's indicative of an issue. If you had been hearing such a noise as of late (when the car was still running) I would actually be inclined to do that first before cranking the engine more, just in case--i.e. check that before doing a compression test. You can find some find some videos online on how to remove the cover there. To actually change the tensioner and chain, you do need to also remove the valve cover and you need special tools to do the chain (can get them off Amazon fairly cheap though); and the bolt in the cam phaser/exhaust cam is not easy to remove. But I think checking the chain may be a priority before worrying about replacement parts/tools.

You also have an underboost code there. This is probably also separate. This could be something as simple as a boost leak from a loose clamp or hose, but can also be something much more severe--the wastegate arm on the turbo. If you've been hearing about the class action/settlement about this as of late...well this is what it is. However cars this old don't have any coverage only reimbursement for previous repairs done so not really applicable. The repair for this is typically "a new turbocharger"--not exactly cheap, nor is it an easy DIY given the location of the turbo (it's doable of course, just not super easy). But anyway this would not stop the car from running so one thing at a time--just a note for now about the P0299 code.