P1171

Diagnostic Chart:

Schematic:

The PCM 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 closed loop operation (by heavy acceleration), the PCM will provide more fuel to the engine. Under these conditions, the PCM should detect a rich condition. If you do not detect a rich exhaust at this time, a DTC P1171 will set. A plugged fuel filter or a restricted fuel line can prevent adequate amounts of fuel from being supplied during the power enrichment mode.

DTC PARAMETERS
DTC P1171 will set if O2S Sensor 1 voltage is less than 300 mV for 5 seconds during power enrichment mode and the following conditions have been met:
^ DTCs P0131, P0132, P0133, P0134 and P1133 are not set.
^ Engine coolant temperature is greater than 20°C (68°F).
^ The engine has been running for longer than 20 seconds.
^ The system is in closed loop operation.

DIAGNOSTIC AIDS
^ A restricted fuel filter can supply adequate amounts of fuel at idle, but may not be able to supply enough fuel during a heavy acceleration.
^ Water or alcohol in the fuel may cause a low O2S 1 voltage during acceleration.
^ Check for an adequate amount of fuel in the fuel tank.
^ When the engine is idling or at steady cruise, the O2S 1 voltage should vary from between approximately 100 mV to 900 mV During the power enrichment mode, more fuel is needed and O2S 1 voltage should rise above 447 mV
^ Check for malfunctioning or plugged injector(s).