GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2000 🢒 Eldorado 🢒 Engine 🢒 Engine Controls - 4.6L 🢒 Restricted Exhaust System Check

Step

Action

Value(s)

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 the rear HO2 sensor (HO2S bank 2). Refer to Heated Oxygen Sensor Replacement - Bank 2 .
  2. Install J 35314-A exhaust back pressure tester, or equivalent in place of the HO2 sensor.
  3. Start and idle the engine.
  4. Observe the exhaust system back pressure reading on the gauge.

Does the reading exceed the specified value?

8.6 kPa (1.25 psi)

Go to Step 4

Go to Step 3

3
  1. Leave the exhaust back pressure tester in place of the HO2 sensor.
  2. Increase the engine speed to 2000 RPM.
  3. Observe the exhaust system back pressure reading on the gauge.

    4. Does the reading exceed the specified value?

20.7 kPa (3 psi)

Go to Step 4

System OK

4
  1. Reinstall HO2S bank 2 sensor 1. Refer to Heated Oxygen Sensor Replacement - Bank 2 .
  2. Remove the Post HO2 sensor (HO2S bank 1 sensor 2). Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 .
  3. Install the exhaust back pressure tester and/or the equivalent in place of HO2S bank 1 sensor 2.
  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?

20.7 kPa (3 psi)

Go to Step 5

Go to Step 6

5

Locate and repair the restriction in the exhaust system past the catalytic converter. Possible faults include the following:

    • Collapsed pipe
    • Heat distress
    • Internal muffler failure.

Is action complete?

--

Go to Step 8

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6
  1. Check for restriction forward of the catalytic converter.
  2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 8

Go to Step 7

7

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

Is action complete?

--

Go to Step 8

--

8
  1. Remove the rear HO2 sensor (HO2S bank 2). Refer to Heated Oxygen Sensor Replacement - Bank 2 .
  2. Install the J 35314-A exhaust back pressure tester, or equivalent in place of the HO2 sensor.
  3. Start and idle the engine.
  4. Observe the exhaust system back pressure reading on the gauge.

Does the reading exceed the specified value?

8.6 kPa (1.25 psi)

Go to Step 4

Go to Step 9

9
  1. Leave the exhaust back pressure tester in place of the HO2 sensor.
  2. Increase the engine speed to 2000 RPM.
  3. Observe the exhaust system back pressure reading on the gauge.

Does the reading exceed the specified value?

20.7 kPa (3 psi)

Go to Step 4

System OK