P0171

Tests 223 - 227:

Tests 228 - 230:

Tests 231 - 234:

Tests 235 - 236:

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 pump module defective
- TPS voltage change not smooth
- TPS Voltage < 0.92 volts
- Fuel inlet strainer plugged
- 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