GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Vivant 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Tachometer Inaccurate or Inoperative

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. If the coolant temperature gage works, skip Steps 3-10 and go directly to Step 11. The coolant temperature gage uses the same fuse and ground as the tachometer.

Step

Action

Values

Yes

No

1

Check the engine DTCs.

Does the scan tool indicate any current vehicle speed sensor (VSS) DTCs?

--

Go to Step 2

Go to Step 3

2

Diagnose and repair any VSS DTCs before continuing with this table.

Are the VSS DTCs cleared?

--

Go to Step 3

--

3

Inspect fuse F16.

Is fuse F16 open?

--

Go to Step 5

Go to Step 4

4
  1. Inspect for a short circuit and repair it, if necessary.
  2. Replace fuse F16.

Did you complete the repair?

--

System OK

--

5
  1. Turn ON the ignition.
  2. Measure the voltage at fuse F16.

Does the voltage measure within the specified value?

11-14 V

Go to Step 7

Go to Step 6

6

Repair the power supply for fuse F16.

Did you complete the repair?

--

System OK

--

7
  1. Disconnect the instrument cluster connector.
  2. Turn ON the ignition.
  3. Measure the voltage at the instrument cluster connector terminal C1.

Does the voltage measure within the specified value?

11-14 V

Go to Step 9

Go to Step 8

8

Repair the open circuit between fuse F16 and instrument cluster connector terminal C1.

Did you complete the repair?

--

System OK

--

9

With the instrument cluster disconnected, use an ohmmeter to measure the resistance between the instrument cluster connector terminal C12 and ground.

Does the resistance measure the specified value?

0 ohms

Go to Step 11

Go to Step 10

10

Repair the open circuit between ground and the instrument cluster connector terminal C12.

Did you complete the repair?

--

System OK

--

11

Inspect for a defect on the instrument cluster printed circuit.

Is the printed circuit inoperative?

--

Go to Step 12

Go to Step 13

12

Replace the instrument cluster.

Did you complete the replacement?

--

System OK

--

13

With the instrument cluster disconnected, use an ohmmeter to measure for an open circuit between the electronic control module (ECM) and the instrument cluster connector terminal C2.

Does the resistance measure the specified value?

0 ohms

Go to Step 15

Go to Step 14

14

Repair the open circuit between the instrument cluster connector terminal C2 and the ECM.

Did you complete the repair?

--

System OK

--

15

Replace the tachometer.

Does the new tachometer function properly?

--

System OK

Go to Step 16

16

Replace the ECM.

Did you complete the repair?

--

System OK

--