Circuit/System Verification
IMPORTANT:
Disregard any transmission symptoms, antilock brake system (ABS) indicators, and traction control system (TCS) indicators until any fuel trim faults are repaired. A fuel trim fault may cause default actions such as harsh shifts and illumination of the ABS/TCS indicators.
- Verify that other DTCs are not set.
- If any DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- Allow the engine to reach operating temperature. With the engine running, observe the HO2S 1 parameter with a scan tool. The HO2S 1 value should vary from approximately 40 mV to approximately 900 mV, and respond to fueling changes.
- If the value does not vary from approximately 40 mV to approximately 900 mV, refer to DTC P0030, P0036, P0053, P0054, P0135, or P0141 , DTC P0131, P0132, P0137, or P0138 , or DTC P0133, P0134, P0140, P1133, P1134, P2A00, or P2A01 .
- The normal Short Term FT parameter should be between +10 percent and -10 percent, with near 0 percent the optimum, with the engine running at operating temperature.
- The Long Term FT parameter should be between +10 percent and -10 percent, with near 0 percent the optimum, with the engine running at operating temperature.
IMPORTANT:
The EVAP purge enablement may cause the FT to be momentarily outside the normal range.