P0172

Tests 206 - 210:

Test 211:

SYMPTOM LIST
P-0172 1/1 FUEL SYSTEM RICH

TEST NOTE:
All symptoms listed above are diagnosed using the same tests. The title for the tests will be P-0171 1/1 FUEL SYSTEM LEAN.

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

SET CONDITION
PCM conducts a test to determine whether fuel system is running too rich. If this happens for 2 trips, MIL illuminates & trouble code is stored. MIL remains on for more than 1 trip but goes out if conditions that set code are not found on subsequent trips

POSSIBLE CAUSES
- Coolant sensor calibration failure
- Engine mechanical problem
- Fuel pressure out of specification
- Upstream O2 sensor heater defect
- Fuel system rich or lean does not reoccur