Questions and Answers
Volkswagen GTI DTCs And Drive Cycles
Q. I own a 2001 Volkswagen GTI 1.8 liter turbo with manual transmission and 51,000 miles. My check engine light is on. I checked the computer and it came up with two codes P0171, System too lean, and P0411, secondary air injection system, incorrect flow. The only thing I did was change my air filter. However I'm not sure this will solve the problem.
Now, I was going to erase the codes to see if the problem was solved. But, my code reader manual said to do a OBD ll Drive Cycle to set all monitors to a done status. Then it said to consult my vehicles service manual. Well, my service manual doesn't even mention a Drive Cycle. Can I reset the computer? Will the monitors be on a done status without a OBD ll Drive Cycle?
I had a recall on my Ignition coils, and my service manual shows how to take the old coils out, not the new ones. How do I take them off to change my spark plugs? There are no screws like the old ones. I'm also getting a fluttering sound when I shift from one gear to the next. Clutch or Turbo?
A. The OBD II system is designed to clear codes by itself when problems no longer persist. It is almost always better to let the system clear itself thus providing assurance that any intermittent problems are actually cured.
In the case of your P0171 code, you could have a dirty or clogged fuel filter, if you haven't changed it recently, I recommend you change it soon.
The manufacturer does not provide a procedure for clearing diagnostic trouble codes without a scan tool.
To remove the new coils, you just need to pull them up and out. There is a circlip that locks them to the spark plug.
Readiness Monitors and Drive Cycles:
"Readiness Monitors" are indicators that demonstrate whether or not emission system components are being monitored (checked) by the OBD-II system.
If a monitor is set to "Ready" the monitor is checking its assigned component and, if no DTC's are present, the vehicle should pass an emissions test.
The status of all readiness monitors is reset to "Not Ready":
- Each time DTC's are cleared
- The battery is disconnected
- The ECM is disconnected
The status of all readiness monitors is reset to "Ready":
- After DTC's are cleared and the appropriate drive cycle(s) is successfully completed
Completing the Drive Cycle successfully one (1) time should reset most drive cycle monitors to a "Ready" status. However, there are "two trip" monitors, which require that the drive cycle be successfully completed two (2) times, to achieve a "Ready" status. Furthermore, systems which use averaging, may require the drive cycle to be completed more than 2 times.
Before Beginning the Drive Cycle:
Check the status of the Readiness Monitors, check for DTC's, correct faults, clear DTC's before beginning the Drive Cycle.
Begin Drive Cycle:
The vehicle should be driven approximately 7.5 miles within a period of approx. 23 minutes (1372 seconds) from a cold start. However, due to manufacture variations, it is necessary to perform only as much of the Drive Cycle as is necessary to reset the required monitors to a "Ready" status. Operate the throttle smoothly to obtain best results. Do not shut the engine off during the drive cycle.
CAUTION: Obey all traffic laws and drive in a safe manner!
NOTE: Extreme driving conditioning such as very high/low temperatures, rough roads and high altitudes may prevent some monitors from attaining a "Ready" status.
Step 1 (Engine Cold) Start engine, idle 20 seconds. Accelerate gradually and drive at 20-25 mph for 1 minute, varying speed. Step 2 Accelerate gradually to 32 mph within 35 seconds. Decelerate to 0 mph in 10 seconds. Idle for 40 seconds. Step 3 Accelerate at part throttle to 25 mph in 10 seconds. Cruise at 17-25 mph for 15 seconds. Accelerate gradually to 57 mph in 45 seconds. Cruise at 50-56 mph for 1 minute. Decelerate gradually to 0 mph in 40 seconds. Idle for 15 seconds. Step 4 Accelerate at part throttle to 36 mph and maintain for 10 seconds. Decelerate to 0 mph in 15 seconds. Idle for 5 seconds. Step 5 Accelerate to 30 mph and back to 0 mph within 30 seconds. Idle for 20 seconds. Step 6 Accelerate to 36 mph in 20 seconds. Drive at 35 mph for 20 seconds. Decelerate to 0 mph in 15 seconds. Idle 5 seconds. Step 7 Accelerate gradually to 26 mph and decelerate to 0 within 40 seconds. Idle 15 seconds. Step 8 Accelerate to 27 mph in 40 seconds. Decelerate to 0 mph in 10 seconds. Idle 25 seconds. Step 9 Accelerate to 26 mph in 15 seconds, maintain speed for 10 seconds, decelerate to 0 mph in 10 seconds. Idle 15 seconds. Step 10 Accelerate to 23 mph in 20 seconds, decelerate to 0.5 mph in 10 seconds (no complete stop). Accelerate to 28 mph and back to 0 mph (momentary stop 1 second) within 35 seconds. Step 11 Accelerate gradually to 34 mph in 45 seconds. Vary speed between 34 and 19 mph for 2 minutes. Decelerate from 25 to 0 mph in 25 seconds. Idle for 5 seconds. Step 12 Accelerate to 29 mph in 15 seconds, decelerate gradually to 0 mph in 45 seconds. Idle for 30 seconds. Step 13 Accelerate gradually to 28 mph and back to 0 mph (momentary stop 1 second) within 50 seconds. Accelerate gradually to 27 mph and back to 0 mph within 55 seconds. Idle for 15 seconds. Step 14 Accelerate to 24 mph and back to 0 mph within 18 seconds. Idle for 10 seconds. Accelerate gradually to 22 mph and back to 0 mph within 50 seconds. Idle for 8 seconds. Step 15 Accelerate gradually to 30 mph within 50 seconds. Decelerate to 0 mph in 10 seconds. Idle for 25 seconds. Step 16 Accelerate to 23 mph and back to 0 mph within 30 seconds. Idle for 10 seconds. Step 17 Repeat steps 1 - 16 once again. Recheck the status of the "Readiness Monitors".
NOTE: Remember, clearing DTC's or interrupting power to the ECM after the readiness monitors have been reset to "Ready" will require that the Drive Cycle be repeated.
Additional Information provided courtesy of AllDATA
Additional Information provided courtesy of AllDATA