Diagnostic Test
- CHECK FOR AN ACTIVE DTC NOTE:
A new rear O2 Sensor along with an aging front O2 Sensor may cause the DTC to set. Review the repair history of the vehicle before continuing.
NOTE:If an O2 Sensor DTC set along with the Catalytic Converter Efficiency DTC diagnose the O2 Sensor DTCs before continuing.
NOTE:Check for contaminants that may have damaged the O2 Sensor and Catalytic Converter: contaminated fuel, unapproved silicone, oil and coolant, repair necessary.
- Start the engine.
- Allow the engine to reach normal operating temperature.
- With the scan tool, read DTCs.NOTE:
It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.
Is the DTC active or pending?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION . .
- VISUALLY INSPECT CATALYTIC CONVERTER
- Inspect the Catalytic Converter for the following damage:
- Damage Catalytic Converter, dents or holes.
- Severe discoloration caused by overheating the Catalytic Converter.
- Catalytic Converter broke internally.
- Inspect both ends of the converter, inlet and outlet.
- Leaking Catalytic Converter.
Were any problems found?
Yes
- Replace the Catalytic Converter. Repair the condition that may have caused the failure. Refer to CONVERTER, CATALYTIC, REMOVAL .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST . .
No
- Go To 3
- Inspect the Catalytic Converter for the following damage:
- CHECK THE (K902) O2 SENSOR 2/1 RETURN CIRCUIT VOLTAGE
- CHECK THE (K904) O2 SENSOR 2/2 RETURN CIRCUIT VOLTAGE
- CHECK THE (K902) O2 SENSOR 2/1 RETURN CIRCUIT FOR A SHORT TO GROUND
- Turn the ignition off.
- Disconnect the PCM C2 harness connector.
- Check for continuity between ground and the (K902) O2 Sensor 2/1 Return circuit at the O2 Sensor 2/1 harness connector.
Is there continuity between ground and the (K902) O2 Sensor 2/1 Return circuit?
Yes
- Repair the (K902) O2 Sensor 2/1 Return circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST . .
No
- Go To 6
- CHECK THE (K902) O2 SENSOR 2/1 RETURN CIRCUIT FOR AN OPEN/HIGH RESISTANCE CAUTION:
Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.
- Connect the (special tool #10436, Adapter, GPEC Diagnostic).
- Measure the resistance of the (K902) O2 Sensor 2/1 Return circuit from the O2 Sensor 2/1 harness connector to the GPEC Adaptor.
Is the resistance below 3.0 Ohms?
Yes
- Go To 9
No
- Repair the (K902) O2 Return Upstream circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST . .
- CHECK THE (K904) O2 SENSOR 2/2 RETURN CIRCUIT FOR A SHORT TO GROUND
- Turn the ignition off.
- Disconnect the PCM C2 harness connector.
- Check for continuity between ground and the (K904) O2 Sensor 2/2 Return circuit at the O2 Sensor 2/2 harness connector.
Is there continuity between ground and the (K904) O2 Sensor 2/2 Return circuit?
Yes
- Repair the (K904) O2 Sensor 2/2 Return circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST . .
No
- Go To 8
- CHECK THE (K904) O2 SENSOR 2/2 RETURN CIRCUIT FOR AN OPEN/HIGH RESISTANCE CAUTION:
Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.
- Connect the (special tool #10436, Adapter, GPEC Diagnostic).
- Measure the resistance of the (K904) O2 Sensor 2/2 Return circuit from the O2 Sensor 2/2 harness connector to the GPEC Adaptor.
Is the resistance below 3.0 Ohms?
Yes
- Go To 9
No
- Repair the (K904) O2 Sensor 2/2 Return circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST . .
- CHECK RELATED PCM AND COMPONENT CONNECTIONS
- Perform any Service Bulletins that apply.
- Disconnect all PCM harness connectors.
- Disconnect all related in-line harness connections (if equipped).
- Disconnect the related component harness connectors.
- Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
- Proper connector installation.
- Damaged connector locks.
- Corrosion.
- Other signs of water intrusion.
- Weather seal damage (if equipped).
- Bent terminals.
- Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
- Terminals that have been pushed back into the connector cavity.
- Check for spread terminals and verify proper terminal tension.
Repair any conditions that are found.
- Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
- Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
- Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
- With the scan tool, erase DTCs.
- Test drive or operate the vehicle in accordance with the when monitored and set conditions.
- With the scan tool, read DTCs.
Did the DTC return?
Yes
- Replace the Powertrain Control Module in accordance with the Service information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST . .
No
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST . .
- Test complete.
- CHECKING THE EXHAUST SYSTEM FOR LEAKS
- Perform the CHECKING THE EXHAUST SYSTEM FOR LEAKS test procedure. Refer to CHECKING THE EXHAUST SYSTEM FOR LEAKS
.
Were any exhaust leaks found?
Yes
- Repair or replace the leaking exhaust parts as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST . .
No
- Go To 11
- Perform the CHECKING THE EXHAUST SYSTEM FOR LEAKS test procedure. Refer to CHECKING THE EXHAUST SYSTEM FOR LEAKS
.
- ENGINE MECHANICAL CONDITION
- Check the exhaust for excessive smoke caused by an internal problem in the engine.
Is an engine mechanical condition present?
Yes
- Repair the engine mechanical condition as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST . .
No
- Go To 12
- Check the exhaust for excessive smoke caused by an internal problem in the engine.
- AGING O2 SENSOR
- A new Downstream O2 Sensor along with an aging Upstream O2 Sensor may cause the DTC to set.
- Review the vehicles repair history.
Has the Downstream O2 Sensor been replaced without replacing the Upstream O2 Sensor?
Yes
- Replace the front O2 Sensor as necessary. Refer to CONVERTER, CATALYTIC, REMOVAL .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST . .
No
- Go To 13
- CATALYTIC CONVERTER
If there are no possible cause remaining, view repair.
Repair
- Replace the Catalytic Converter. Refer to CONVERTER, CATALYTIC, REMOVAL .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST . .