GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 1999 🢒 Century (China) (CNG) 🢒 Body and Accessories 🢒 Instrument Panel, Gauges, and Console 🢒 Speedometer and/or Odometer Inoperative

Step

Action

Value(s)

Yes

No

1

Did you inspect the vehicle for any instrument cluster Diagnostic Trouble Codes (DTCs)?

--

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

2

Was the Instrument Cluster Diagnostic System Check performed?

--

Go to Step 3

Go to Diagnostic System Check - Instrument Cluster

3

Was the Powertrain Control Module Diagnostic System Check performed?

--

Go to Step 4

Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls

4
  1. Install a scan tool.
  2. Turn the ignition switch to the RUN position.
  3. Select speedometer gauge sweep test under output control main menu.

Does the speedometer gauge perform a full sweep when commanded?

--

Go to Step 6

Go to Step 5

5
  1. Replace the instrument cluster. Refer to Instrument Cluster Replacement .
  2. Inspect the system.

Is the repair complete?

--

Go to Diagnostic System Check - Instrument Cluster

--

6
  1. Ensure that the scan tool is still connected to the DLC connector.
  2. Drive the vehicle.
  3. Compare the scan tool speed display to the instrument cluster speed display.

Do the two speeds agree with each other?

--

Go to Step 7

Go to Step 8

7

Inspect the following components:

    • The speedometer
    • The odometer

Are both components inaccurate?

--

Go to Step 8

Go to Step 9

8

Inspect the vehicle for the following application information:

    • The correct tire size
    • The PCM calibration
    • The vehicle speed sensor

Are these component applications correct?

--

Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls

Go to Step 9

9
  1. Recalibrate the PCM using the correct application for the vehicle. Refer to Powertrain Control Module Replacement/Programming .
  2. Inspect the system.

Is repair complete?

--

System OK

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