GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Cruise Control System Check?

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Go to Step 2

Go to Cruise Control System Check

2

  1. Disconnect the connector C2 at the powertrain control module (PCM).
  2. Place the ignition switch in the RUN position.
  3. Connect a digital multimeter (DMM), set on volts, between the PCM connector C2 pin B9 for the CKT 420 (PPL) wire and ground.
  4. Observe the DMM.
  5. Depress the brake pedal.
  6. Observe the DMM.

Is there battery voltage with the brake pedal released and no voltage with the brake pedal depressed?

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Go to Step 4

Go to Step 3

3

  1. Disconnect the connector at the stoplamp switch.
  2. Connect a DMM, set on volts, between the stoplamp switch connector cavity E for the CKT 420 (PPL) wire and ground.

Is there battery voltage?

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Go to Step 5

Go to Step 6

4

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls.

Is the repair complete?

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Go to Cruise Control System Check

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5

Repair the short to voltage on the CKT 420 (PPL) or CKT 379 (BRN/WHT) wire between the stoplamp switch and the PCM. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Cruise Control System Check

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6

Adjust or replace the stoplamp switch. Refer to Stop Lamp Switch Replacement .

Is the repair complete?

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Go to Cruise Control System Check

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