GM Service Manual Online
For 1990-2009 cars only

Restricted Exhaust System Check

Step

Action

Value(s)

Yes

No

1

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

--

Go to Step 2

Go to the Powertrain On Board Diagnostic (OBD) System Check

2

  1. Remove the HO2S Bank 1 sensor 1.
  2. Install the J 35314-A Exhaust Back Pressure Tester or equivalent in place of the HO2S.
  3. Allow the engine to idle at the normal operating temperature.
  4. Increase the engine speed to 2000 RPM.
  5. Observe the exhaust system back pressure reading on the gauge.

Does the reading exceed the specified value?

90°-95°C (194°-203°F)

20.7 kPa (3 psi)

Go to Step 3

Go to Step 6

3

  1. Reinstall HO2S Bank 1 sensor 1.
  2. Remove HO2S Bank 1 sensor 2.
  3. Install the J 35314-A exhaust back pressure tester or equivalent in place of the HO2S.
  4. Allow the engine to idle at the specified operating temperature.
  5. Increase the engine speed to 2000 RPM.
  6. Observe the exhaust system back pressure reading on the gauge.

Does the reading exceed the specified value?

90°-95°C (194°-203°F)

20.7 kPa (3 psi)

Go to Step 4

Go to Step 5

4

Repair the restriction in the exhaust system after the catalytic converter. Possible faults include:

    • A collapsed pipe
    • Heat distress
    • An internal muffler failure

Is the action complete?

--

Go to Step 6

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5

Notice: Find and repair any problems that may cause converter damage in order to prevent damage to the replacement catalytic converter.

Replace the Bank 1 Catalytic Converter.

Is the action complete?

--

Go to Step 6

--

6

  1. Remove the HO2S Bank 2 sensor 1.
  2. Install the J 35314-A exhaust back pressure tester or equivalent in place of the HO2S.
  3. Allow the engine to idle at the specified operating temperature.
  4. Increase the engine speed to 2000 RPM.
  5. Observe the exhaust system back pressure reading on the gauge.

Does the reading exceed the specified value?

90°-95°C (194°-203°F)

20.7 kPa (3 psi)

Go to Step 7

System OK

7

  1. Reinstall the HO2S Bank 2 sensor 1.
  2. Remove the HO2S Bank 2 sensor 2.
  3. Install the J 35314-A exhaust back pressure tester or the equivalent in place of the HO2S.
  4. Allow the engine to idle at the normal operating temperature.
  5. Increase the engine speed to 2000 RPM.
  6. Observe the exhaust system back pressure reading on the gauge.

Does the reading exceed the specified value?

90°-95°C (194°-203°F)

20.7 kPa (3 psi)

Go to Step 8

Go to Step 9

8

Repair the restriction in the exhaust system past the catalytic converter. The possible faults include:

    • A collapsed pipe
    • Heat distress
    • Internal muffler failure

Is the action complete?

--

Go to Step 10

--

9

Notice: Find and repair any problems that may cause converter damage in order to prevent damage to the replacement catalytic converter.

Replace the Bank 2 catalytic converter.

Is the action complete?

--

Go to Step 10

--

10

Operate the vehicle under the same conditions (as closely as possible) as when the original symptom occurred.

Is the original symptom still present?

--

Go to Step 3

Go to Step 11

11

Are other driveability symptoms still present?

--

Go to Symptoms

System OK