P2099

TEST 1 - 3:

TEST 4 - 6:

SYMPTOM
P2098-DOWN STREAM FUEL SYSTEM 2/2 LEAN
P2099-DOWN STREAM FUEL SYSTEM 2/2 RICH


TEST NOTE
All symptoms listed above are diagnosed using the same tests. The title for the tests will be P2098-DOWN STREAM FUEL SYSTEM 2/2 LEAN.

WHEN MONITORED
With the engine running in closed loop mode, the ambient/battery temperature above (-7° C) 20° F, altitude below 8500 ft and fuel level greater than 15%.

SET CONDITION
If the PCM adds downstream short term compensation to 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
- Good trip equal to zero
- Exhaust leak
- Engine mechanical problem
- O2 sensor
- O2 signal circuit
- O2 return circuit
- Fuel contamination