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Restricted Exhaust

Restricted Exhaust

Test Description

The numbers below refer to the step numbers on the diagnostic table.

3

The exhaust system has very low back pressure under normal conditions. If the exhaust system is restricted, a significant increase in the exhaust pressure is noticed on an exhaust back pressure gauge.

Removing the heated oxygen (HO2S) sensor may set a diagnostic trouble code (DTC). When finishing this diagnostic table, be sure to clear all codes.

4

This step will isolate the catalytic converter from the remainder of the exhaust system.

Step Action Yes No
1

Did you verify the customers complaint?

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2

Did you review the exhaust symptoms diagnostic information and perform the necessary inspections?

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Go to Symptoms - Engine Exhaust



Warning

While engine is operating, the exhaust system will become extremely hot. To prevent burns avoid contacting a hot exhaust system.



1. Remove the pre-catalyst HO2S. Refer to one of the following:

• Heated Oxygen Sensor Replacement - Sensor 1 for the 2.0L engine.

• Heated Oxygen Sensor Replacement (LBY/A20DTR) Heated Oxygen Sensor Replacement (LBS/A20DTH) for the 2.0L diesel engine.

• Heated Oxygen Sensor Replacement - Sensor 1 for V6.

2. Install the an exhaust back pressure gauge in place of the HO2S.

3. Start and run the vehicle.

4. Increase the engine speed to 2 500 rpm. Monitor the engine speed.

5. Diesel only: Perform a manual regeneration of the particle filter

6. Observe the exhaust system back pressure reading on the gauge.

• Diesel: Must not exceed 4 KPa

• Petrol: Must not exceed 0,5 KPa


Does the reading exceed the specified value?

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1. Turn the engine OFF and place the ignition in the lock position.

2. Remove an exhaust back pressure gauge.

3. Install the pre-catalyst HO2S. Refer to one of the following:

• Heated Oxygen Sensor Replacement - Sensor 1 for the 2.0L engine.

• Heated Oxygen Sensor Replacement (LBY/A20DTR) Heated Oxygen Sensor Replacement (LBS/A20DTH) for the 2.0L diesel engine.

• Heated Oxygen Sensor Replacement - Sensor 1 for V6.

4. Remove the post-catalyst HO2S. Refer to one of the following:

• Heated Oxygen Sensor Replacement - Sensor 2 for the 2.0L engine.

• Heated Oxygen Sensor Replacement - Sensor 2 for V6.

5. Install the an exhaust back pressure gauge in place of the post HO2S.

6. Start the engine.

7. Increase the engine speed to 2 500 rpm. Monitor the engine speed.

8. Diesel only: Perform a manual regeneration of the particle filter

9. Observe the exhaust system back pressure reading on the gauge.

• Diesel: Must not exceed 4 KPa

• Petrol: Must not exceed 0,5 KPa


Does the reading exceed the specified value?

Go to

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5

Inspect the exhaust system for the following conditions:


• Damage in the exhaust pipe

• Debris in the exhaust pipe

• Muffler or resonator internal failure

• Muffler or resonator internal failure

• Two-layer exhaust pipe separation


Did you find and correct the condition?

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6

Replace the catalytic converter. Refer to Catalytic Converter Replacement (LAU/A28NER) Catalytic Converter Replacement (LBY/A20DTR) Catalytic Converter Replacement (LLU/A16LET) Catalytic Converter Replacement (LBS/A20DTH) Catalytic Converter Replacement (LHU/A20NFT) Catalytic Converter Replacement (LHU/A20NFT - AWD) .

Did you find and correct the condition?

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7


1. Remove an exhaust back pressure gauge.

2. Install the post-catalyst HO2S. Refer to one of the following:

• Heated Oxygen Sensor Replacement - Sensor 2 for the 2.0L engine.

• Heated Oxygen Sensor Replacement - Sensor 2 for V6.

3. Clear any codes.

4. Road test the vehicle in order to verify the repair.


Did you correct the condition?

System OK

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