P1171 - FAULT CODE - OBD2

P1171 Code failures by brands

P1171 ACURA, BUICK, CADILLAC, CHEVROLET, GMC, HONDA, ISUZU: FUEL SYSTEM LEAN DURING ACCELERATION.

Description of DTC code P1171

You can determine from the internal circuitry of the ECM (Engine Control Module) if the automobile's fuel system may deliver the necessary amounts of fuel during conditions that require higher acceleration or power enrichment. When a PE (Power Enrichment) mode is requested for high acceleration during closed-loop operations, the ECM sends a larger amount of fuel to the engine. The ECM must detect that a rich mixture is present during such conditions.

If the rich condition is not detected at that time, the DTC P1171 OBDII code will be set, showing that there is a fuel system leaning during increased acceleration requirements.

Symptoms of fault code P1171

Check Engine light ON.
Unstable motor operation.

Causes of OBD2 P1171

Reasons for setting the P1171 OBD2 diagnostic code:

A fuel filter or fuel line may be restricted.
The amount of fuel available may not be the amount needed.
The fuel could have contamination levels.
A fuel injector may be in bad condition.
An oxygen sensor may be faulty.

Possible solutions of the DTC code P1171

To troubleshoot the P1171 OBDII fault code, take into account these suggestions:

Consult the Technical Service Bulletins.
Use a scan tool, you need to check for other stored DTCs. Pay special attention to the codes that indicate faults with HO2S1.
Check that the available amount of fuel is adequate. Likewise, it is necessary to verify that this compound does not present contamination levels.
Verify the injectors, filters, and fuel lines do not present blockages or restrictions. In case you find inconsistencies in these, make corrections.
Observe the voltage of the Front Heated Oxygen Sensor (HO2S1) with a scanner while accelerating the engine above 1200 rpm. The voltage should have variations between 100 and 900 mV, and at certain times, alternate above the specified voltage. If this is not the case, it is necessary to perform advanced diagnostics on the sensor.