P1171

System Description
The Powertrain Control Module (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 "Closed Loop" operation (by heavy acceleration), the PCM will provide 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 will set. 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 O2S 1 voltage is less than 300 mV for 5 seconds.
- The O2S 1 operating in "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 not set; P0131, P0132, P0133, P0134.

Action Taken When the DTC Sets
- The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.

Conditions for Clearing the DTC
- A history DTC will clear after 40 consecutive warm up cycles without a fault.
- DTCs can be cleared by using a scan tool.

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 fuel may cause low O2S 1 voltage during acceleration.
- Check for a faulty or plugged fuel injectors.

DTC P1171 - Inadequate Fuel Flow:

Test Description
Numbers below refer to the step numbers on the Diagnostic Table.
1. The OBD System Check prompts the Technician to complete some basic checks and store the Freeze Frame Data and the Failure records on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. This information on the scan tool can be referred to later.
4. When the engine is idling or at a steady cruise, the O2S 1 voltage should vary from approximately 100 mV to 900 mV. During power enrichment mode, more fuel is needed and O2S 1 voltage should rise above 447 mV.