GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 Prizm 🢒 Body and Accessories 🢒 Cruise Control 🢒 DTC 021

Circuit Description

The Vehicle speed sensor (VSS) provides vehicle speed input voltage to the instrument cluster and in turn to the cruise control module.

Diagnostic Aids

Check for the following:

Short to ground or an open condition in the PPL/WHT wires between the instrument cluster assembly, junction block 3, and the cruise control module.

Inspect the wiring harness and components for any of the following conditions:

    • Backed out terminals
    • Improper mating of terminals
    • Broken electrical connectors locks
    • Improperly formed or damaged terminals
    • Faulty terminal to wire connections
    • Physical damage to the wiring harness
    • A broken wire inside the insulation
    • Corrosion of electrical connections, splices, or terminals

Repair any electrical circuit faults that were found. Refer to Wiring Repairs in Wiring Systems.

Test Description

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

  1. This step tests for a short to ground or an open condition in the PPL/WHT wire which supplies VSS signal voltage to the cruise control module.

    2.

  2. This step tests for a short to ground in the PPL/WHT wire which supplies VSS signal voltage from the instrument cluster assembly to junction block 3

Step

Action

Yes

No

Schematic Reference: Cruise Control Schematics

1

Did you perform the Diagnostic System Check - Cruise Control ?

Go to Step 2

Go to Diagnostic System Check - Cruise Control

2

  1. Turn OFF the ignition.
  2. Disconnect connector C1 on junction block 3 which is located behind the center of the instrument panel.
  3. Disconnect the cruise control module connector which is located . next to the instrument panel compartment on the RH side of the instrument panel.
  4. Test the VSS vehicle speed input circuit between the junction block 3 and the cruise control module for an open or ground condition. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 6

Go to Step 3

3

  1. Disconnect connector C2 on junction block 3 which is located behind the center of the instrument panel.
  2. Disconnect the cruise control module connector which is located . next to the instrument panel compartment on the RH side of the instrument panel.
  3. Test the VSS vehicle speed output circuit between the junction block 3 and the cruise control module for an open or ground condition. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 6

Go to Step 4

4

Inspect for poor connections at the harness connector of the cruise control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 6

Go to Step 5

5

Replace the cruise control module. Refer to Cruise Control Module Replacement .

Did you Complete the replacement?

Go to Step 6

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6
  1. Turn OFF the ignition.
  2. Remove the STOP fuse.
  3. Remove the ECU-B fuse.
  4. Wait 30 seconds.
  5. Reinstall STOP and ECU-B fuses.
  6. Turn ON the ignition, with the engine OFF.
  7. Using the jumper, connect the DLC terminals Tc and E1.

Does the CRUISE indicator lamp flash the same trouble code?

Go to Step 2

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