Diagnostic Procedures
- Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK . Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. After performing OBD system check, go to next step.NOTE: If engine has been operating, allow engine to cool for about 30 minutes before proceeding with tests.
- Turn ignition on, engine off. Using scan tool, read HO2S 2 voltage. If voltage is greater than 600 mV or less than 300 mV, see DIAGNOSTIC AIDS. If voltage is not as specified, go to next step.
- Inspect HO2S 2 ignition feed fuse. If fuse is open, go to step 15). If fuse is okay, go to next step.
- Turn ignition off. Raise and support vehicle. Disconnect HO2S 2 harness connector. Connect a test light between chassis ground and HO2S 2 ignition feed circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 7).
- Connect test light between HO2S 2 harness connector ignition feed and heater ground circuits. If test light illuminates, go to next step. If test light does not illuminate, go to step 8).
- Allow HO2S 2 to cool for at least 10 minutes. Using DVOM, check resistance between ignition feed and heater ground circuits at HO2S 2. If resistance is 5-6 ohms, go to step 9). If resistance is not as specified, go to step 14).
- Repair open HO2S 2 ignition feed circuit. After repairs, go to step 16).
- Repair open HO2S 2 heater ground circuit. After repairs, go to step 16).
- Check for faulty connection at HO2S 2. If faulty connection is found, repair as necessary and go to step 16). If connection is okay, go to next step.
- Turn ignition off. Disconnect PCM connectors. Check resistance of HO2S 2 signal and ground circuits. If resistance on either circuit is greater than 5 ohms, repair open or faulty connection as necessary and go to step 16). If resistance is 5 ohms or less, go to next step.
- Check for faulty connection at HO2S 2 harness connector. If faulty connection is found, repair as necessary. After repairs, go to step 16). If connection is okay, go to next step.
- Check for faulty ground circuit connection at PCM. If faulty connection is found, repair as necessary. After repairs, go to step 16). If connection is okay, go to next step.
- Check for faulty HO2S 2 signal circuit connection at PCM. If faulty connection is found, repair as necessary. After repairs, go to step 16). If connection is okay, go to next step.
- Replace HO2S 2. After replacing sensor, go to step 16).
- Locate and repair short to ground in HO2S 2 ignition feed circuit, replace fuse. After repairs, go to next step.
- Allow engine to cool completely. Using scan tool, clear DTCs. Turn ignition on, engine off. Read HO2S 2 voltage. If voltage is greater than 600 mV or less than 300 mV, repair is complete. If voltage is not as specified, return to step 2).