Fault Code 16825/P0441/001089 - EVAP Emission Control Sys: Incorrect Flow
http://wiki.ross-tech.com/wiki/index.ph ... 441/001089
OBDII Codes Engine Light Definitions Diagnostic Repair | AutoCodes
Overview -
This is a rather common fault, especially for older TT's since it can take a while for the EVAP system to develop problems. Basically the two primary culprits are the EVAP N80 valve and/or EVAP Charcoal Canister. Since the N80 is basically a solenoid driven valve, the electronics and/or valve diaphragm can wear out and fail. While the Canister has no working parts, it can fail when the charcoal becomes saturated with fuel.
The typical reason for the N80 to fail prematurely is because it can become clogged with debris in the EVAP system; specifically little bits of charcoal that make their way from the Canister into the N80 caused by over fueling. Over fueling (e.g. adding gas after the nozzle clicks off, or "topping up the pipe") can result in excess fuel ending up in the EVAP Canister which then dissolves the charcoal and ultimately contaminates the canister. If repeatedly over fueled, contaminated charcoal can start to break down within 3,000-miles, leading to early N80 failures.
If the canister is saturated with fuel, it can also be a reason you may smell fuel vapors since the canister is not sealed. if you look carefully on the side, you'll see a vent pipe pointing down. This allows the fuel vapors to vent through the charcoal and not pressurize the fuel system.
If you don't want to go through the effort of trouble-shooting the issues, simply remove and replace the parts starting with the N80. They're relatively inexpensive items and straight forward DIY projects. As noted, start with the gas cap first and go from there. But having said that, make sure your gas cap is on tight and the o-ring isn't damaged first.
If these DIY solutions don't solve the problem, verify the P/N on your N80 EVAP Purge Valve and EVAP Canister before ordering new ones to ensure the parts are a one-to-one replacement. In some cases, it may be cheaper to get them directly from Audi than from eBay or other re-sellers. After installation, clear the faults and re-scan to verify the fault is gone.
Typical items that may be a cause of the fault, in order of checking, and DIY repair and/or replacement -
1.) Fuel Cap -
Check that your gas cap is on properly and that the o-ring isn't damaged. Try swapping gas caps with a new, or known good one. If the o-ring is damaged, it can be replaced as a separate item. Clear the faults and re-scan to verify the fault is gone.
2.) EVAP Canister Purge Regulator Valve (N80) -
Since the N80 can get clogged with debris, you'll need to check that that the internals are clear and clean and verify the solenoid is functioning. In the illustration below, there are two parts that make up the N80; #28 Solenoid Valve and #29 Thrust Ring. The Thrust Ring is simply a rubber housing for the N80 that fits onto a metal tab on the valve cover.
a. Check the terminal resistance using a multi-meter. It should be within 22-30 Ohms. If it is within specified value it's still fine but it could be clogged. To check that the solenoid is working, manually apply 12-V power and ground using test leads to see if the valve is opening or perform the VCDS test listed below. In the the un-powered state the valve is closed.
b. Remove and inspect the valve. Use Carburetor Cleaner to clean out any debris that may be inside. With the valve open, blow compressed air in reverse direction to dislodge any debris. It's also worth removing and spraying the associated hoses to remove any debris that may have accumulated.
c. N80 VCDS Test - Go into 01 Engine Electronics, 04 Basic Settings, Groups 070 & 071 (EVAP leak and EVAP flow) to verify the N80 purge valve function. There's also a drop down in the 01-Engine Output tests for "Evap System Purge Control Valve (N80)". See this post for reference -
https://www.ttforum.co.uk/forum/viewtop ... 0&start=15
d. Perform a vacuum leak check to ensure the valve isn't leaking.
Other faults that may point to the N80 include:
3.) EVAP (Charcoal) Canister Faulty Pipe Seal or Fuel Contamination -
The most common cause of fuel in the EVAP Canister is filling gas up to the top of the pipe which results in fuel in the EVAP Canister. Excess fuel can saturation the charcoal inside the EVAP Canister which can lead to charcoal debris ending up in the N80, thus triggering the resulting fault codes. Note - locations of the EVAP (Charcoal) Canister differs between Euro and US models.
a. Check that the tubes on the top of the canister are fitted properly and verify that the o-ring is present (Item #10). You can apply silicone sealant around the tube fittings to resolve the leak. However, if this doesn't solve the problem and the fault doesn't go away, the charcoal may be saturated with fuel and the canister needs to be replaced. Verify the P/N on your EVAP canister and replace. Clear the faults and re-scan to verify the fault is gone.
b. As noted above for the N80, it may be worth removing the primary canister vent pipe and cleaning it out with Carburetor Cleaner to remove any charcoal debris that may have accumulated.
If these DIY solutions don't solve the problem, there may be a leak somewhere in the EVAP system. This may require a trip to a garage since the average DIY won't have the equipment necessary to perform a complete EVAP system leak test.
Here are a couple of other people's experiences with changing the canister for no other reason than it seemed like a good idea. Since you can pick these up off eBay for cheap, it's probably worth doing at some point especially for high mileage vehhicles -
https://www.ttforum.co.uk/forum/viewtop ... 3#p9127703
https://www.ttforum.co.uk/forum/viewtop ... &t=1887561
EVAP System Reference YouTube videos -
How The VW Evap Purge Valves N80 Fails
VW Evaporative Emission Systems (EVAP) - Operation and Testing
EVAP DIY Repair YouTube videos -
N80 (Evap Purge Regulator) Valve DIY (How to) Install on 2.0T FSI
PDF Reference Downloads -
EVAP Operation and Diagnosis Self-Study Program
View attachment EVAP Operation and Diagnosis Self-Study Program.pdf
Audi TT Coupé '07 Self-Study Program SSP-380
View attachment SSP 380 Audi TT Coupé ‘07.pdf
![EVAP Canister and N80 Valve.JPG]( "EVAP Canister and N80 Valve.JPG")
![3 2007 3.2 (German Spec) 2.JPG]( "3 2007 3.2 (German Spec) 2.JPG")
![2 2007 3.2 (German Spec).JPG]( "2 2007 3.2 (German Spec).JPG")
![1 Charcoal Canister.JPG]( "1 Charcoal Canister.JPG")
![4 N80 Filter and Charcoal Debris.JPG]( "4 N80 Filter and Charcoal Debris.JPG")
View attachment SSP 380 Audi TT Coupé ‘07.pdf
View attachment EVAP Operation and Diagnosis Self-Study Program.pdf
http://wiki.ross-tech.com/wiki/index.ph ... 441/001089
OBDII Codes Engine Light Definitions Diagnostic Repair | AutoCodes
Overview -
This is a rather common fault, especially for older TT's since it can take a while for the EVAP system to develop problems. Basically the two primary culprits are the EVAP N80 valve and/or EVAP Charcoal Canister. Since the N80 is basically a solenoid driven valve, the electronics and/or valve diaphragm can wear out and fail. While the Canister has no working parts, it can fail when the charcoal becomes saturated with fuel.
The typical reason for the N80 to fail prematurely is because it can become clogged with debris in the EVAP system; specifically little bits of charcoal that make their way from the Canister into the N80 caused by over fueling. Over fueling (e.g. adding gas after the nozzle clicks off, or "topping up the pipe") can result in excess fuel ending up in the EVAP Canister which then dissolves the charcoal and ultimately contaminates the canister. If repeatedly over fueled, contaminated charcoal can start to break down within 3,000-miles, leading to early N80 failures.
If the canister is saturated with fuel, it can also be a reason you may smell fuel vapors since the canister is not sealed. if you look carefully on the side, you'll see a vent pipe pointing down. This allows the fuel vapors to vent through the charcoal and not pressurize the fuel system.
If you don't want to go through the effort of trouble-shooting the issues, simply remove and replace the parts starting with the N80. They're relatively inexpensive items and straight forward DIY projects. As noted, start with the gas cap first and go from there. But having said that, make sure your gas cap is on tight and the o-ring isn't damaged first.
If these DIY solutions don't solve the problem, verify the P/N on your N80 EVAP Purge Valve and EVAP Canister before ordering new ones to ensure the parts are a one-to-one replacement. In some cases, it may be cheaper to get them directly from Audi than from eBay or other re-sellers. After installation, clear the faults and re-scan to verify the fault is gone.
Typical items that may be a cause of the fault, in order of checking, and DIY repair and/or replacement -
1.) Fuel Cap -
Check that your gas cap is on properly and that the o-ring isn't damaged. Try swapping gas caps with a new, or known good one. If the o-ring is damaged, it can be replaced as a separate item. Clear the faults and re-scan to verify the fault is gone.
2.) EVAP Canister Purge Regulator Valve (N80) -
Since the N80 can get clogged with debris, you'll need to check that that the internals are clear and clean and verify the solenoid is functioning. In the illustration below, there are two parts that make up the N80; #28 Solenoid Valve and #29 Thrust Ring. The Thrust Ring is simply a rubber housing for the N80 that fits onto a metal tab on the valve cover.
a. Check the terminal resistance using a multi-meter. It should be within 22-30 Ohms. If it is within specified value it's still fine but it could be clogged. To check that the solenoid is working, manually apply 12-V power and ground using test leads to see if the valve is opening or perform the VCDS test listed below. In the the un-powered state the valve is closed.
b. Remove and inspect the valve. Use Carburetor Cleaner to clean out any debris that may be inside. With the valve open, blow compressed air in reverse direction to dislodge any debris. It's also worth removing and spraying the associated hoses to remove any debris that may have accumulated.
c. N80 VCDS Test - Go into 01 Engine Electronics, 04 Basic Settings, Groups 070 & 071 (EVAP leak and EVAP flow) to verify the N80 purge valve function. There's also a drop down in the 01-Engine Output tests for "Evap System Purge Control Valve (N80)". See this post for reference -
https://www.ttforum.co.uk/forum/viewtop ... 0&start=15
d. Perform a vacuum leak check to ensure the valve isn't leaking.
Other faults that may point to the N80 include:
- Check Engine Light
- System Lean P0171
- System Rich P0172
- EVAP Purge Valve P0441
- Very Small Leak Detected P0456
- Incorrect Flow 16825/P0441/001089
3.) EVAP (Charcoal) Canister Faulty Pipe Seal or Fuel Contamination -
The most common cause of fuel in the EVAP Canister is filling gas up to the top of the pipe which results in fuel in the EVAP Canister. Excess fuel can saturation the charcoal inside the EVAP Canister which can lead to charcoal debris ending up in the N80, thus triggering the resulting fault codes. Note - locations of the EVAP (Charcoal) Canister differs between Euro and US models.
a. Check that the tubes on the top of the canister are fitted properly and verify that the o-ring is present (Item #10). You can apply silicone sealant around the tube fittings to resolve the leak. However, if this doesn't solve the problem and the fault doesn't go away, the charcoal may be saturated with fuel and the canister needs to be replaced. Verify the P/N on your EVAP canister and replace. Clear the faults and re-scan to verify the fault is gone.
b. As noted above for the N80, it may be worth removing the primary canister vent pipe and cleaning it out with Carburetor Cleaner to remove any charcoal debris that may have accumulated.
If these DIY solutions don't solve the problem, there may be a leak somewhere in the EVAP system. This may require a trip to a garage since the average DIY won't have the equipment necessary to perform a complete EVAP system leak test.
Here are a couple of other people's experiences with changing the canister for no other reason than it seemed like a good idea. Since you can pick these up off eBay for cheap, it's probably worth doing at some point especially for high mileage vehhicles -
https://www.ttforum.co.uk/forum/viewtop ... 3#p9127703
https://www.ttforum.co.uk/forum/viewtop ... &t=1887561
EVAP System Reference YouTube videos -
How The VW Evap Purge Valves N80 Fails
VW Evaporative Emission Systems (EVAP) - Operation and Testing
EVAP DIY Repair YouTube videos -
N80 (Evap Purge Regulator) Valve DIY (How to) Install on 2.0T FSI
PDF Reference Downloads -
EVAP Operation and Diagnosis Self-Study Program
View attachment EVAP Operation and Diagnosis Self-Study Program.pdf
Audi TT Coupé '07 Self-Study Program SSP-380
View attachment SSP 380 Audi TT Coupé ‘07.pdf
View attachment SSP 380 Audi TT Coupé ‘07.pdf
View attachment EVAP Operation and Diagnosis Self-Study Program.pdf
