HB3 - Check Fuel Trim PID Status

- Key On, engine running.

- Verify engine at operating temperature.

- Scan Tool connected.

- Access Fuel B1 and Fuel B2 PIDs.

- Verify PIDs, read CL and O2S indicating closed loop and oxygen sensor signal.

- Access LFT 1, LFT 2, SFT 1, and SFT 2 PIDs.

- While at idle, view PIDs.

- Increase engine speed to 2,000 rpm and return to idle.

- Do the PID numbers change from positive to negative, or visa versa at least once on LFT and at a faster rate on SFT?

YES -- Problem may be intermittent. GO to Pinpoint Test Step Z1 with the following data: FPW, HO2S, LFT, MAF and SFT PIDs and list of Possible Causes. Z1 - Intermittent Test Procedure

NO -- GO to HB4. HB4 - Check Continuity of Injector Harness