Caution: While engine is operating, the exhaust system will become extremely hot. To prevent burns avoid contacting a hot exhaust system.
Important: Do not replace a restricted particulate filter. Repair the engine condition that clogged the particulate filter, and then attempt the perform a service regeneration. Refer to Exhaust Particulate Filter Cleaning .
If the vehicle is equipped with a 6.6L diesel engine do not perform this diagnostic. The exhaust system does not have a location for installing the J 35314-A Exhaust Back Pressure Gage. Instead remove the suspect component, operate the vehicle, verify for improved performance. If performance is improved then replace the faulty component.
The numbers below refer to the step numbers on the diagnostic table.
The exhaust system has a very low back pressure under normal conditions. If the exhaust system is restricted, a significant increase in the exhaust pressure is noticed on the J 35314-A .
Removing the AIR check valve or HO2S sensor may set a DTC. When finishing this diagnostic table, be sure to clear all codes.
This step will isolate the catalytic converter from the remainder of the exhaust system.
Confirming that the condition has been fixed is essential. If the symptom still exists and the vehicle has a dual exhaust system, proceed to step 2 and repeat the diagnostic procedure on the opposite exhaust pipe.
Step | Action | Value(s) | Yes | No | ||||||||||||||||||||||||
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1 | Did you verify the customers complaint? | -- | Go to Step 2 | -- | ||||||||||||||||||||||||
2 | Did you review the exhaust symptoms diagnostic information and perform the necessary inspections? | -- | Go to Step 3 | |||||||||||||||||||||||||
3 | Is the vehicle equipped with a 6.6L diesel engine? | -- | Go to Diagnostic Aids | Go to Step 4 | ||||||||||||||||||||||||
Does the reading exceed the specified value? | 20 kPa (3 psi) If equipped with a 4.8L, 5.3L, or 6.0L-3.4 kPa (0.5 psi) | Go to Step 5 | Go to Step 8 | |||||||||||||||||||||||||
Does the reading exceed the specified value? | 20 kPa (3 psi) If equipped with a 4.8L, 5.3L, or 6.0L-3.4 kPa (0.5 psi) | Go to Step 6 | Go to Step 7 | |||||||||||||||||||||||||
6 | Inspect the exhaust system for the following conditions:
Did you find and correct the condition? | -- | Go to Step 8 | -- | ||||||||||||||||||||||||
7 | Replace the catalytic converter. Refer to Catalytic Converter Replacement . Did you find and correct the condition? | -- | Go to Step 8 | -- | ||||||||||||||||||||||||
Did you correct the condition? | -- | System OK | Go to Step 2 |