GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2000 🢒 Grand Prix 🢒 Restraints 🢒 SIR 🢒 Head Up Display (HUD) Speedometer Inaccurate

Step

Action

Value(s)

Yes

No

1

Has the vehicle been checked for diagnostic trouble codes (DTCs)?

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Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 3.1L (LG8) or Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 3.8L

2
  1. Connect a scan tool to the data link connector (DLC).
  2. Drive the vehicle and compare the scan tool speed display in engine data 1 to the instrument cluster speed display.

Does both the IPC and scan tool display same speed?

--

Go to Step 3

Go to Step 6

3

Does both the HUD and scan tool display the same speed?

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Go to Step 4

Go to Step 9

4

Inspect the vehicle for the following applications:

    • Tire Size
    • PCM Calibration
    • Vehicle speed sensor application

Are the component applications correct?

--

Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 3.1L (LG8) or Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 3.8L

Go to Step 4

5
  1. Replace the following components as needed:
    2. • The tires
    • The vehicle speed sensor
  2. Recalibrate the PCM if needed. Refer to one of the following procedures:
    3. •  Powertrain Control Module Replacement/Programming in Engine Controls - 3.1L (LG8)
  3. Inspect the system.

Is the repair complete?

--

System OK

--

6

Inspect circuit 389 between connector C1 terminal K at the IPC and connector C2 terminal C8 at the underhood accessory wiring junction block for high resistance, poor connections, or a short to ground.

Is the wiring in circuit 389 showing signs of excessive resistance, poor connections or a short to ground?

--

Go to Step 7

Go to Step 8

7

Repair circuit 389.

Is the repair complete?

--

System OK

--

8

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

Is the repair complete?

--

System OK

--

9

Inspect circuit 389 between terminal A7 at the HUD and connector C2 terminal E8 at the underhood accessory wiring junction block for high resistance, poor connections, or a short to ground.

Is the wiring in circuit 389 showing signs of excessive resistance, poor connections, or a short to ground?

--

Go to Step 10

Go to Step 11

10

Repair circuit 389.

Is the repair complete?

--

System OK

--

11

Replace the HUD. Refer to Head Up Display Module Replacement .

Is the repair complete?

--

System OK

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