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Engine-Codes.com | All About OBDII Engine Codes

P0171 Isuzu

P0171 Isuzu - Fuel Trim System Lean Bank 1

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P0171 Isuzu Comments |  Add Comment
Possible causes
- Intake air leaks
- Faulty front heated oxygen sensor
- Ignition misfiring
- Faulty fuel injectors
- Exhaust gas leaks
- Incorrect fuel pressure
- Lack of fuel
- Faulty Mass Air Flow (MAF) sensor
- Incorrect Positive Crankcase Ventilation (PCV) hose connection
Help with Possible causes What does this mean?
Tech notes
If the P0171 is combined with the P0174 code, it's very likely that the problem is caused by an intake leak. If there are no intake leaks, the next step is to replaced the air filter and clean the air flow meter. If the problem persist the front oxygen (O2) sensor may need to be replaced.
Help with Tech Notes What does this mean?
When is the code detected?
- Fuel injection system does not operate properly.
- The amount of mixture ratio compensation is too small. (The mixture ratio is too lean.)
Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Excessive Fuel Consumption
P0171 Isuzu Description

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. The Engine Control Module (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 Malfunction Indicator Light (MIL) (2 trip detection logic).

ISUZU Technical Service Bulletins for P0171 code
2006 ISUZU I-280 Fuel System, Gasoline:fuel Injection System Details
2006 ISUZU I-350 Fuel System, Gasoline:fuel Injection System Details
2007 ISUZU I-290 Fuel System, Gasoline:fuel Injection System Details
2007 ISUZU I-370 Fuel System, Gasoline:fuel Injection System Details
2003 ISUZU ASCENDER Fuel System, Gasoline:fuel Injection System Details
2004 ISUZU ASCENDER Fuel System, Gasoline:fuel Injection System Details
2005 ISUZU ASCENDER Fuel System, Gasoline:fuel Injection System Details
2006 ISUZU ASCENDER Fuel System, Gasoline:fuel Injection System Details
2007 ISUZU ASCENDER Fuel System, Gasoline:fuel Injection System Details
2003 ISUZU ASCENDER 073000 Fuel System, Gasoline:fuel Injection System Details
More Bulletins Help with Technical Service Bulletins What does this mean?
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