GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1998 🢒 Seville 🢒 Engine 🢒 Engine Controls - 4.0L and 4.6L 🢒 Restricted Exhaust System Check

Restricted Exhaust System Check

Step

Action

Value(s)

Yes

No

1

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

--

Go to Step 2

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

2
  1. Remove HO2S Bnk 1 sensor 2
  2. Install Exhaust Back pressure tester J 35314-A, BT 8515, BT 8603 or equivalent in place of HO2S Bnk 1 sensor 2
  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

3
  1. With exhaust Back pressure tester J 35314-A, BT 8515, BT 8603 or equivalent in place of HO2S Bnk 1 sensor 2, 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

4
  1. Reinstall HO2S Bnk 1 sensor 2.
  2. Remove HO2S Bnk 1 sensor 3
  3. Install exhaust Back pressure tester J 35314-A, BT 8515, BT 8603 or equivalent in place of HO2S Bnk 1 sensor 3
  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

5

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

    • Collapsed pipe
    • Heat distress
    • Internal muffler failure

Is the action complete?

--

Go to Step 7

--

6

Replace the Three-Way Catalytic Converter.

Is action complete?

--

Go to Step 7

--

7
  1. Remove HO2S 1.
  2. Install Exhaust Back pressure tester J 35314-A, BT 8515, BT 8603 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

8
  1. With exhaust back pressure tester J 35314-A, BT 8515, BT 8603 or equivalent 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

Repair complete.