GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 1999 🢒 Isuzu MD Steel Tilt (F Model) 🢒 Body and Accessories 🢒 Instrument Panel, Gauges, and Console 🢒 Engine Coolant Temperature Gage Inaccurate or Inoperative

Step

Action

Value(s)

Yes

No

1

Operate the engine and compare the actual engine coolant temperature with the temperature indicated by the instrument cluster temperature gauge.

Is the deviation between the engine coolant temperature and the indicated coolant temperature within the specified value?

-1°C (30°F)

Go to Step 2

Go to Step 3

2

Check the operation of the cooling system.

Is the cooling system operating properly?

--

System OK

--

3
  1. Disconnect the connector at the engine coolant temperature gauge sensor.
  2. Connect one red lead of a J 33431-C at engine coolant temperature gauge sensor connector terminal A for CKT 4 and CKT 135 (DK GRN), and CKT 385 and CKT 23 (GRN).
  3. Connect the other lead to ground.
  4. Adjust the tester to 1,305 ohms and observe the temperature gauge reading.
  5. Adjust the tester to 49.5 ohms and observe the temperature gauge reading.
  6. The temperature gauge should indicate approximately 38°C(100°F), then approximately 100°C(260°F).

Does the temperature gauge indicate the specified cold and then hot values?

38°C (100°F)

126°C (260°F)

Go to Step 7

Go to Step 4

4

Check the temperature gauge.

Did the temperature gauge indicate a value significantly below the specified value for hot at 49.5 ohms?

126°C (260°F)

Go to Step 5

Go to Step 8

5
  1. Disconnect the 17 way IP harness connector at the instrument cluster.
  2. Connect a J 39200 between instrument cluster connector terminal C16 and terminal A (Diesel) or C (Gas) of the engine coolant temperature gauge sensor connector terminal A for CKT 4 and CKT 135 (DK GRN), and CKT 385 and CKT 23 (GRN).

Are the wire resistances of CKT 4 and CKT 135 (DK GRN), and CKT 385 and CKT 23 (GRN) above the specified value?

20 ohms

Go to Step 6

Go to Step 8

6
  1. Locate the high resistance in CKT 4 and CKT 135 (DK GRN), and CKT 385 and CKT 23 (GRN) between the instrument cluster and the engine coolant temperature gauge sensor.
  2. Repair the high resistance.

Is the repair complete?

--

System OK

--

7

Replace the engine coolant temperature sensor. Refer to Engine Coolant Temperature Sensor Replacement .

Is the repair complete?

--

System OK

--

8

Replace the instrument panel cluster. Refer to Instrument Cluster Replacement .

Is the repair complete?

--

System OK

--