Diagnostic Test
WARNING: This page is about a different car, the 2024 Jeep Grand Wagoneer L and 2024 Jeep Grand Wagoneer. However, it is still accessible from the selected car via links, so may be relevant.
- READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN
- With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
- For future reference, with the scan tool, run and save a vehicle Scan Report and all related recorded data.
- With the scan tool, erase all DTCs.
- Turn the ignition off for a minimum of 10.0 seconds.
- Turn the ignition on.
- Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.
- With the scan tool, read DTCs.
Did the DTC return?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
- CHECK FOR OTHER DTCS
- Refer to the recorded DTCs.
Are there any Upstream or Downstream O2 Sensor DTCs present?
Yes
- Perform the applicable O2 Sensor diagnostic procedure(s) before continuing with this diagnostic procedure. Refer to OXYGEN SENSOR(S) .
No
- Go To 3
- Refer to the recorded DTCs.
- VISUALLY INSPECT CATALYTIC CONVERTER
- Inspect the Catalytic Converter inlet and outlet for the following damage:
- Physical damage (dents or holes) to the Catalytic Converter.
- Catalytic Converter leaking.
- Catalytic Converter internally broken.
- Severe discoloration caused by overheating the 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 AND INSTALLATION .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 4
- Inspect the Catalytic Converter inlet and outlet for the following damage:
- CHECK 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 5
- Perform the CHECKING THE EXHAUST SYSTEM FOR LEAKS test procedure. Refer to CHECKING THE EXHAUST SYSTEM FOR LEAKS
.
- CHECK THE 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 6
- Check the exhaust for excessive smoke caused by an internal problem in the engine.
- CHECK FOR AN AGING UPSTREAM O2 SENSOR AND NEW DOWNSTREAM O2 SENSOR NOTE:
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 OXYGEN SENSOR(S) .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 7
- Review the vehicles repair history.
- REPLACE THE CATALYTIC CONVERTER
If there are no possible cause remaining, view repair.
Repair
- Replace the Catalytic Converter in accordance with the Service Information. Refer to CONVERTER, CATALYTIC, REMOVAL AND INSTALLATION .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .