GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

B+

2

2

--

--

5-Volt Reference

2

2

2

--

Position Sensor Signal

2

2

2

--

Adjustable Pedal Inhibit Signal

B3631 02

B3631 05

B3631 05

--

Adjustable Pedal Control

1

2

2

--

Motor Control A

2

2

2

--

Motor Control B

2

2

2

--

Position Sensor Low Reference

--

2

--

--

Adjustable Pedal Module Ground

--

2

--

--

1. Adjustable Pedal Inhibit Inoperative

2. Adjustable Pedals Inoperative

Circuit/System Description

The adjustable pedal system is controlled by the adjustable pedal switch and enabled by the adjustable pedal module so that operation can occur only while the transmission selector lever is in the PARK position. The adjustable pedals are moved forward or backward by an actuator which is fixed to the accelerator pedal actuator with a drive cable to the brake pedal actuator. The actuator is controlled by the adjustable pedal switch through two motor control circuits. Battery voltage is supplied to the switch from the PEDAL fuse. In the inactive state, both switch contacts are closed to the ground contacts within the switch. When the switch is activated in the forward or rearward direction, the appropriate switch contact is closed to the battery voltage supply contact within the switch. The actuator is bidirectional and the direction of the pedal assembly travel is determined by which of the motor control circuits is switched to battery voltage while the other remains grounded.

The adjustable pedal switch is grounded through the adjustable pedal module and system operation is enabled or disabled by the module by opening or closing the switch ground. The adjustable pedal module monitors the movement of the brake pedal assembly while the adjuster motor is in an active state in order to ensure that both pedal assemblies are moving and a step over condition is not being created. If at any time the system is attempted to be operated and no movement of the brake pedal assembly is detected, the system will be disabled. The adjustable brake pedal position sensor is a potentiometer type position sensor and is supplied with a 5-volt reference and low reference from the module, and the position sensor signal circuit is referenced from 5 volts within the module.

The adjustable pedal system will be disabled by the adjustable pedal module anytime the transmission selector lever is not in the park position while the ignition is on. While the system is being disabled, the body control module (BCM) supplies battery voltage to the adjustable pedal module through the adjustable pedal inhibit signal circuit.

Diagnostic Aids

If adjustable pedal operation has been disabled by the adjustable pedal module, the PEDAL fuse must be removed for several seconds in order to reset the module and allow normal operation to resume once the proper repairs have been made.

Reference Information

Schematic Reference

Adjustable Pedal Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Adjustable Pedals Description and Operation

Electrical Information Reference

    •  Testing for Intermittent Conditions and Poor Connections
    •  Circuit Testing
    •  Wiring Repairs
    •  Connector Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON with the transmission in PARK, verify the scan tool Adj. Pedals Inhibit Cmd. parameter is Inactive.
  2. If not the specified value, correct the cause of the adjustable pedal inhibit before continuing with this diagnostic.
  3. Press the forward portion of the adjustable pedal switch. The pedals should move towards the driver.
  4. Press the rearward portion of the adjustable pedal switch. The pedals should move away from the driver.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the adjustable pedal module.
  2. Ignition OFF, test for less than 3.0 ohms between the ground circuit terminal E and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal H and ground.
  5. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  6. Verify that a test lamp does not illuminate between the signal circuit terminal G and ground.
  7. If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  8. Ignition OFF, connect the harness connector at the adjustable pedal module. Disconnect the harness connector at the adjustable pedal position sensor.
  9. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C and ground.
  10. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the adjustable pedal module.
    If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the adjustable pedal module.
  11. Ignition OFF, connect the harness connector at the adjustable pedal position sensor. Disconnect the harness connector at the adjustable pedal module.
  12. Ignition ON, verify that a test lamp does not illuminate between the circuits listed below and ground:
  13. • Signal circuit terminal B
    • Low reference circuit terminal D
    If the test lamp illuminates, test the appropriate circuit for a short to voltage.
  14. Verify that a test lamp does not illuminate between the circuits listed below and B+:
  15. • Signal circuit terminal B
    • Low Reference circuit terminal D
    If the test lamp illuminates, test the appropriate circuit for a short to ground.
  16. Test for 9-10k ohms between the 5-volt reference circuit terminal F and the low reference circuit terminal D.
  17. If not within the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, test or replace the adjustable pedal position sensor.
  18. Test for 0.5-10k ohms between the 5-volt reference circuit terminal F and the signal circuit terminal B.
  19. If not within the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, test or replace the adjustable pedal position sensor.
  20. Ignition OFF, connect the harness connector at the adjustable pedal module. Disconnect the harness connector at the adjustable pedal position switch.
  21. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal A and ground.
  22. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  23. Verify that a test lamp illuminates between the B+ circuit terminal A and the signal circuit terminal E.
  24. If the test lamp does not illuminate, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the adjustable pedal module.
  25. Ignition OFF, reconnect the harness connector at the adjustable pedal position switch. Disconnect the harness connector at the adjustable pedal actuator.
  26. Connect a test lamp between the control circuit terminal A and ground.
  27. Ignition ON, press and release the Rearward portion of the adjustable pedal position switch. The test lamp should turn ON and OFF when pressing and releasing the switch.
  28. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, test or replace the adjustable pedal position switch.
    If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the adjustable pedal position switch.
  29. Connect a test lamp between the control circuit terminal B and ground.
  30. Press and release the Forward portion of the adjustable pedal position switch. The test lamp should turn ON and OFF when pressing and releasing the switch.
  31. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, test or replace the adjustable pedal position switch.
    If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the adjustable pedal position switch.
  32. Connect a test lamp between the control circuit terminal A and the control circuit terminal B.
  33. Alternately press and release the Forward and Rearward portions of the adjustable pedal position switch. The test lamp should turn ON and OFF when pressing and releasing the switch.
  34. If the test lamp does not illuminate, test or replace the adjustable pedal position switch.
  35. If all circuits test normal, replace the adjustable pedal module.

Component Testing

Adjustable Pedal Position Switch

  1. Ignition OFF, disconnect the harness connector at the adjustable pedal position switch.
  2. Test for infinite resistance between the B+ circuit terminal A and the signal circuit terminal E.
  3. If less than the specified value, replace the adjustable pedal position switch.
  4. Test for infinite resistance between the B+ circuit terminal A and the follow terminals:
  5. • Control circuit terminal F
    • Control circuit terminal B
    If less than the specified value, replace the adjustable pedal position switch.
  6. Test for less than 2.0 ohms between the signal circuit terminal E and the follow terminals:
  7. • Control circuit terminal F
    • Control circuit terminal B
    If greater than the specified range, replace the adjustable pedal position switch.
  8. With the switch in the forward position, test for less than 2.0 ohms between the B+ circuit terminal A and the control circuit terminal F.
  9. If greater than the specified range, replace the adjustable pedal position switch.
  10. With the switch in the rearward position, test for less than 2.0 ohms between the B+ circuit terminal A and the control circuit terminal B.
  11. If greater than the specified range, replace the adjustable pedal position switch.

Adjustable Pedal Position Sensor

  1. Ignition OFF, disconnect the harness connector at the adjustable pedal position sensor.
  2. Test for 9-10K ohms between the 5-volt reference terminal F and the low reference terminal D.
  3. If not within the specified range replace the adjustable pedal position sensor.
  4. Test for 0.5-10K ohms between the 5-volt reference terminal F and the signal terminal B.
  5. If not within the specified range replace the adjustable pedal position sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Brake and Accelerator Pedal Adjuster Position Sensor Replacement
    •  Adjustable Pedal Module Replacement
    •  Brake and Accelerator Pedal Adjuster Actuator Motor Replacement
    •  Body Control Module Replacement for BCM replacement, setup, and programming.