6E–311
6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P1171 Fuel System Lean During Accelerator
060R100133
Circuit Description
The powertrain control module (PCM) internal circuitry
can identify if the vehicle fuel system is capable of
supplying adequate amounts of fuel during heavy
accelerator (power enrichment). The PCM monitors the
voltage of the oxygen sensor during power enrichment.
When a power enrichment mode of operation is
requested during “closed loop” operation (by heavy
accelerator), the PCM will provide more fuel to the
engine. Under these conditions the PCM should detect a
“rich” condition (high oxygen sensor voltage). If this “rich”
exhaust is not detected at this time, a DTC P1171 will set.
A plugged fuel filter, restricted fuel line, restricted in-tank
filter or defective fuel pump can prevent adequate
amounts of fuel from being supplied during power
enrichment mode.
Conditions for Setting the DTC
D
No related DTCs.
D
Engine is operating in “closed loop power enrichment”
mode for 3 seconds.
D
Engine coolant temperature is above 60
°
C (140
°
F).
D
While in “power enrichment” mode the oxygen sensor
voltage remains below 400 mV for 3 seconds.
Action Taken When the DTC Sets
D
The PCM will not turn the malfunction indicator lamp
(MIL) “ON”.
D
The PCM will store conditions which were present
when the DTC was set as Failure Records only. This
information will not be stored as Freeze Frame data.
Conditions for Clearing the MIL/DTC
D
The PCM will turn the MIL “OFF” on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.
D
A history DTC P1171 will clear after 40 consecutive
warm-up cycles have occurred without a fault.
D
DTC P1171 can be cleared by using the Tech 2 “Clear
Info” function.
Diagnostic Aids
D
A restricted fuel filter or fuel line, restricted in-tank filter,
or a defective fuel pump may supply adequate
amounts of fuel at idle, but may not be able to supply
enough fuel during heavy accelerator.
D
Water or alcohol in the fuel may cause low HO2S
voltage during accelerator.
D
Check for faulty or plugged fuel injector(s).
D
Check for low fuel.
SECTION