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Home >> Cadillac >> 2005 >> DeVille Protection Series >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Instrument Panel System Displays, Gauges And Console >> Diagnostic Information and Procedures >> Speedometer and/or Odometer Inaccurate or Inoperative >> Test Description

Test Description

The number below refers to the step number on the diagnostic table.

  1. 4:  This step tests for the proper vehicle speed signal from the PCM.
Speedometer and/or Odometer Inaccurate or Inoperative

Step Action Value(s) Yes No
Schematic Reference: Instrument Cluster Schematics 
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
  1. Install a scan tool.
  2. Raise the vehicles drive wheels. Refer to Lifting and Jacking the Vehicle in General Information.
  3. Start the engine.
  4. Place the transmission into drive.
  5. With the scan tool, observe the Vehicle Speed Sensor parameter in the powertrain control module (PCM) Engine Data 1 data list.
Does the Vehicle Speed Sensor parameter match the speedometer display?		 - Go to Step 3  Go to Step 4 
3 Does the odometer operate properly? - Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems Go to Step 8 
4 
  1. Turn OFF the ignition.
  2. Disconnect the PCM connector C1.
  3. Turn ON the ignition.
  4. Measure the voltage from the vehicle speed signal circuit to a good ground.
Does the voltage measure greater than the specified value?		 9.0 V Go to Step 6  Go to Step 5 
5 Test the vehicle speed signal circuit for an open, for a high resistance, or for a short to ground between the instrument panel cluster (IPC) and the PCM. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 11  Go to Step 8 
6 Test the vehicle speed signal circuit for a short to battery voltage between the IPC and the PCM. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 11  Go to Step 7 
7 Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 11  Go to Step 9 
8 Inspect for poor connections at the harness connector of the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 11  Go to Step 10 
9 Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 11  -
10 Replace the IPC. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 11  -
11 Operate the system in order to verify the repair.
Did you correct the condition?		 - System OK Go to Step 2 
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