GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Inspect the speedometer.

Does the speedometer work?

--

Go to Step 2

Go to Speedometer and/or Odometer Inoperative

2

  1. Disconnect the engine coolant temperature (gauge) sensor connector.
  2. Connect the instrument panel tester tool J 33431-C between the engine coolant temperature (gauge) sensor harness connector terminal C and ground.
  3. Set the tester to 44 ohms.
  4. Turn the ignition switch to the RUN position.

Does the engine coolant temperature gauge read high, approximately 125°C (260°F)?

--

Go to Step 3

Go to Step 8

3

Set the tester to 1365 ohms.

Does the engine coolant temperature gauge read low, approximately 37°C (100°F)?

--

Go to Step 4

Go to Step 5

4

  1. Inspect the engine coolant temperature sensor connector for a poor connection.
  2. If the connection is OK, replace the engine coolant temperature sensor. Refer to Engine Coolant Temperature Sensor Replacement in Engine Controls - 3.1L (LG8).
  3. Inspect the system.

Is the symptom still present?

--

Go to Step 5

System OK

5

Inspect for a poor connection or a short to voltage in CKT 135.

Does a poor connection or a short to voltage in CKT 135 exist?

--

Go to Step 6

Go to Step 7

6

Repair the poor connection or the short to voltage in CKT 135.

Is the symptom still present?

--

Go to Step 7

System OK

7

  1. Replace the instrument cluster. Refer to Instrument Cluster Replacement .
  2. Inspect the system.

Is the symptom still present?

--

Go to Step 9

System OK

8

Inspect for a poor connection, an open, or a short to ground in CKT 135.

Does a poor connection, an open, or a short to ground in CKT 135 exist?

--

Go to Step 9

Go to Step 7

9

  1. Repair the poor connection, the open, or the short to ground in CKT 135.
  2. Inspect the system.

Is the symptom still present?

--

--

System OK