Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

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Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

1. Remove the pre-catalyst HO2S. Refer to Heated Oxygen Sensor Replacement .
2. Install the J 35314-A Exhaust Back-Pressure Tester in place of the HO2S.
3. Start the engine.
4. Increase and monitor the engine speed at 2500 RPM.
5. Observe the exhaust system back-pressure reading on the gage.

Does the reading exceed the specified value?

9 kPa (1.25 psi)

Go to Step 3

Go to Step 6

1. Turn the engine off and place the ignition in the LOCK position.
2. Remove the J 35314-A .
3. Install the pre-catalyst HO2S. Refer to Heated Oxygen Sensor Replacement .
4. Remove the post-catalyst HO2S. Refer to Heated Oxygen Sensor Replacement .
5. Install the J 35314-A in place of the post-catalyst HO2S sensor.
6. Start the engine.
7. Increase and monitor the engine speed at 2500 RPM.
8. Observe the exhaust system back-pressure reading on the gage.

Does reading exceed the specified value?

9 kPa (1.25 psi)

Go to Step 4

Go to Step 5

Inspect the exhaust system for the following conditions:

Did you find and correct the condition?

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Go to Step 6

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Replace the catalytic converter. Refer to Catalytic Converter Replacement in Engine Exhaust.

Did you find and correct the condition?

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Go to Step 6

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1. Remove the J 35314-A .
2. Install the pre- or post-catalyst HO2S sensor. Refer to Heated Oxygen Sensor Replacement .
3. Clear any codes.
4. Road test the vehicle in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 1