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 HO2S 1. Refer to Heated Oxygen Sensor Replacement .
2. Install the exhaust back pressure tester J 35314-A or equivalent in place of HO2S 1.
3. Engine idling at normal operating temperature
4. Observe the exhaust system back pressure reading on the gauge.

Does the reading exceed the specified value?

8.6 kPa (1.25 psi)

Go to Step 4

Go to Step 3

1. With the exhaust pressure tester in place of HO2S 1, increase the engine speed to 2000 RPM.
2. Observe the exhaust system back pressure reading on the gage.

Does the reading exceed the specified value?

20.7 kPa (3 psi)

Go to Step 4

System OK

Repair restriction in the exhaust system. Possible faults include:

Is the action complete?

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Go to Step 5

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1. With the exhaust pressure tester in place of HO2S 1, increase the engine speed to 2000 RPM
2. Observe the exhaust system back pressure reading on the gauge.

Does the reading exceed the specified value?

20.7 kPa (3 psi)

Go to Step 2

System OK