Diagnostic Test

1) ACTIVE DTC
NOTE: Diagnose and repair any O2 Sensor DTCs before continuing with this test.

NOTE: A new downstream O2 Sensor along with an aging upstream O2 Sensor may cause the DTC to set. Review the vehicle repair history before continuing.

NOTE: It may be necessary to test drive the vehicle within the DTC monitoring conditions in order for this DTC to set.

NOTE: Attempt to operate the vehicle under conditions similar to which the DTC was set. Refer to Freeze Frame information.

Start the engine and allow it to reach operating temperature.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

With a scan tool, select View DTCs.

Is the status Active for this DTC?

Yes
1. Go to 2).
No
1. Refer to the *CHECKING FOR AN INTERMITTENT CONDITION Diagnostic Procedure.
2) CATALYTIC CONVERTER
Thoroughly inspect the catalytic converter for any of the following conditions:

- Damage, dents, or holes

- Severe discoloration caused by overheating

- Internal damage

Were any problems found?

Yes
1. Replace the Catalytic Converter. Repair the condition that may have caused the failure.
2. Perform PCM VERIFICATION TEST .
No
1. Go to 3).
3) CHECKING THE EXHAUST SYSTEM FOR LEAKS
Perform the diagnostic procedure for *CHECKING THE EXHAUST SYSTEM FOR LEAKS .

Were any problems found?

Yes
1. Repair as necessary.
2. Perform PCM VERIFICATION TEST .
No
1. Go to 4).
4) CHECKING THE OXYGEN SENSOR OPERATION
Perform the diagnostic procedure for *CHECKING THE OXYGEN SENSOR OPERATION .

Were any problems found?

Yes
1. Repair as necessary in accordance with the Service Information.
2. Perform PCM VERIFICATION TEST .
No
1. Go to 5).
5) ENGINE MECHANICAL CONDITION
NOTE: Check for signs of contamination that may have damaged the O2 Sensor(s) and Catalytic Converter, such as: contaminated fuel, unapproved silicone, evidence of oil, coolant or anti-seize compound. Repair as necessary.

Check the exhaust for excessive smoke caused by an internal engine problem.

Were any problems found?

Yes
1. Repair the engine mechanical condition in accordance with the Service Information.
2. Perform PCM VERIFICATION TEST .
No
1. Go to 6).
6) UPSTREAM O2 SENSOR
A new downstream O2 Sensor along with an aging upstream O2 Sensor may cause this DTC to set.

Review the vehicle repair history.

Has the downstream O2 Sensor been replaced without replacing the upstream O2 Sensor?

Yes
1. Replace the upstream O2 Sensor as necessary.
2. Perform PCM VERIFICATION TEST .
No
1. Go to 7).
7) CATALYTIC CONVERTER
If there are no possible causes remaining, view repair.

Repair
1. Replace the Catalytic Converter.
2. Perform PCM VERIFICATION TEST .