P0171 - Fuel Injection System Too Lean
10-25-2004 | 06:04 PM
#2
FSM says.....
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1 (front).
The ECM calculates the necessary compensation to correct the offset between the actual and the theoretical ratios. In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the ECM judges the condition as the fuel injection system malfunction and light up the MIL (2 trip detection logic).
Possible Cause:
-Intake air leaks
-Heated oxygen sensor 1 (front)
-Injectors
-Exhaust gas leaks
-Incorrect fuel pressure
-Lack of fuel
-Mass air flow sensor
The ECM calculates the necessary compensation to correct the offset between the actual and the theoretical ratios. In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the ECM judges the condition as the fuel injection system malfunction and light up the MIL (2 trip detection logic).
Possible Cause:
-Intake air leaks
-Heated oxygen sensor 1 (front)
-Injectors
-Exhaust gas leaks
-Incorrect fuel pressure
-Lack of fuel
-Mass air flow sensor
10-26-2004 | 04:59 AM
#4
Senior Member
Joined: Aug 2004
Posts: 119
MAF sensor...just had it done on Oct. 13th.
My SES light came on, codes P0171 & (eventually) P0174..fuel system lean bank 1&2. I had the dealer replace it...cost me $100 under my extended warrantee...and there was also an ECU update or reprogram involved. I didn't have any problems at first, besides more frequent 'pinging'...but as time went on, I lost acceleration power since the MAF sensor wasn't reading the airflow correctly...allowing less fuel, and then cold starts would be stalling and idling rough. All set now.
My SES light came on, codes P0171 & (eventually) P0174..fuel system lean bank 1&2. I had the dealer replace it...cost me $100 under my extended warrantee...and there was also an ECU update or reprogram involved. I didn't have any problems at first, besides more frequent 'pinging'...but as time went on, I lost acceleration power since the MAF sensor wasn't reading the airflow correctly...allowing less fuel, and then cold starts would be stalling and idling rough. All set now.
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