P1171

Diagnostic Chart:

Description:

SYSTEM DESCRIPTION

The PCM's internal circuitry can identify if the vehicle fuel system is capable of supplying adequate amounts of fuel during heavy acceleration (power enrichment). When a power enrichment mode of operation is requested during a Closed Loop operation (by heavy acceleration), the PCM provides additional fuel to the engine. Under these conditions the PCM should detect a rich condition. Whenever this rich exhaust is not detected, a DTC P1171 sets. A plugged fuel filter or restricted fuel line can prevent adequate amounts of fuel from being supplied during power enrichment mode.


CONDITIONS FOR SETTING THE DTC

^ The engine has been running for longer than 20 seconds.

^ The Engine Coolant Temperature (ECT) is greater than 20°C (68°F).

^ The O2S 1 operating in a Closed Loop.

^ The fuel Injector BPW is greater than 0.

^ The fuel delivery system is in the power enrichment mode.

^ One or more of the following DTCs are not set; P0131, P0132, P0133, P0134, P1133.

^ The O2S 1 voltage is less than 300 mV for 5 seconds.


ACTION TAKEN WHEN THE DTC SETS

^ The PCM records the operating conditions at the time the diagnostic fails. The Failure Records buffers stores this information.

^ A history DTC is stored.


CONDITIONS FOR CLEARING THE DTC

^ A history DTC clears after 40 consecutive warm up cycles without a fault.

^ The scan tool can clear the DTC.


DIAGNOSTIC AIDS

^ A restricted fuel filter can supply adequate amounts of fuel at idle, but may not be able to supply enough fuel during heavy acceleration. Water or alcohol in the fuel may cause low O2S 1 voltage during acceleration.

^8Check for faulty or plugged fuel injectors.


TEST DESCRIPTION

Number(s) below refer to the step number(s) on the Diagnostic Table,

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.

4. This step checks to see if the O2S 1 is operating properly.

6. If no malfunctions have been found at this point and no additional DTCs were set, refer to Diagnostic Aids for additional checks and information.