P0171

Test 1:

Tests 2 - 3:

Tests 4 - 7:

Tests 8 - 9:

SYMPTOM
P0171 - 1/1 FUEL SYSTEM LEAN

WHEN MONITORED
With the engine running in closed loop mode, the ambient/battery temperature above 20 °F and altitude below 8000 ft.

SET CONDITION
If the PCM multiplies short term compensation by long term adaptive and a certain percentage is exceeded for two trips, a freeze frame is stored, the MIL illuminates and a trouble code is stored.

POSSIBLE CAUSES
- Fuel filter/pressure regulator (high)
- ECT sensor (out of calibration)
- Engine mechanical problem
- Intermittent fuel system DTC
- Restricted fuel supply line
- TPS voltage change not smooth
- TPS voltage greater than 0.92 volts with throttle closed
- Fuel pump inlet strainer plugged
- Fuel pump module
- MAP sensor (out of calibration)