Was the On-Board Diagnostic (OBD) System Check performed?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

1. Remove HO2S 1 Refer to Heated Oxygen Sensor Replacement .
2. Install 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 gage.

Does reading exceed the specified value?

8.6 kPa (1.25 psi)

Go to Step 4

Go to Step 3

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

Does reading exceed the specified value?

20.7 kPa (3 psi)

Go to Step 4

System OK

1. Reinstall HO2S 1 Refer to Heated Oxygen Sensor Replacement .
2. Remove HO2S 2 Refer to Heated Oxygen Sensor Replacement .
3. Install exhaust back pressure tester J 35314-A or equivalent in place of HO2S 2.
4. Engine at normal operating temperature.
5. Increase engine speed to 2000 rpm.
6. Observe the exhaust system back pressure reading on the gage.

Does reading exceed the specified value?

20.7 kPa (3 psi)

Go to Step 5

Go to Step 6

Repair restriction in the exhaust system past the Three Way Catalytic Converter Possible faults include:

Is the action complete?

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Go to Step 7

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Replace the Three Way Catalytic Converter. Refer to Exhaust System.

Is the action Complete?

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Go to Step 7

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1. Remove HO2S 1. Refer to Heated Oxygen Sensor Replacement .
2. Install 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 gage.

Does reading exceed the specified value?

8.6 kPa (1.25 psi)

Go to Step 4

Go to Step 8

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

Does reading exceed the specified value?

20.7 kPa (3 psi)

Go to Step 5

System OK