GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2000 🢒 Montana Ext. 🢒 Engine 🢒 Engine Controls - 3.4L 🢒 Restricted Exhaust System Check

Restricted Exhaust System Check

Step

Action

Values

Yes

No

1

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

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2
  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. Start the engine and idle at normal operating temperature
  4. Observe the exhaust system back pressure reading on the gauge.

Does reading exceed the specified value?

8.6 kPa (1.25 psi)

Go to Step 4

Go to Step 3

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 gauge.

Does reading exceed the specified value?

20.7 kPa (3 psi)

Go to Step 4

System OK

4
  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. Start the engine and idle at normal operating temperature.
  5. Increase engine speed to 2000 RPM.
  6. Observe the exhaust system back pressure reading on the gauge.

Does reading exceed the specified value?

20.7 kPa (3 psi)

Go to Step 5

Go to Step 6

5

Repair restriction in the exhaust system past the 3-way catalytic converter. Possible faults include:

    •  Collapsed pipe
    •  Heat distress
    •  Internal muffler failure

Did you complete the repair?

--

Go to Step 7

--

6

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

Did you complete the replacement?

--

Go to Step 7

--

7
  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. Start the engine and idle at normal operating temperature.
  4. Observe the exhaust system back pressure reading on the gauge.

Does reading exceed the specified value?

8.6 kPa (1.25 psi)

Go to Step 4

Go to Step 8

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 gauge.

Does reading exceed the specified value?

20.7 kPa (3 psi)

Go to Step 5

System OK