P0171

Tests 220 - 224:

Tests 225 - 226:

Tests 227 - 229:

SYMPTOM LIST
P0171-1/1 FUEL SYSTEM LEAN

TEST NOTE:
All symptoms listed above are diagnosed using the same tests. The title for the tests will be P0171-1/1 FUEL SYSTEM LEAN.

WHEN MONITORED
With the engine running in closed loop mode, the ambient/battery temperature above 20 deg. 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
- TPS voltage change not smooth
- TPS voltage < 0.92 V
- ECT sensor defective (out of calibration)
- MAP sensor defective (out of calibration)
- Engine mechanical problem
- Fuel filter/pressure regulator defective (high)
- Fuel filter/pressure regulator defective (low)
- Fuel pump capacity (volume) out of specs
- Fuel pump defective (low output)