GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2008 🢒 Escalade EXT 🢒 Body Repair 🢒 Bolted Exterior Body Panels and Closures 🢒 Power Tonneau Cover Malfunction

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+

1

1

--

--

X Bus

1

1

1

--

Wake Up Signal

1

1

--

--

Open Signal

1

1

1

--

Close Signal

1

1

1

--

Exit/Learn Switch Signal

1

1

1

--

Cargo Lamp Control

2

2

2

--

Ground

--

1

--

--

1. Power Tonneau Cover Inoperative

2. Cargo Lamp Malfunction

Circuit/System Description

Battery voltage is supplied to the system from the 47 fuse in the underhood fuse block. The system is grounded at the G300 chassis harness ground. The key fobs and exit/learn switch are inputs to the receiver module. The receiver module commands the master motor through the Wake Up, Open, and Close signal circuits and controls the cargo lamp through a low side drive control circuit. The master motor commands the slave motor through an X Bus communication circuit.

Diagnostic Aids

Verify the tracks adequately lubricated and free of obstacles or debris that could bind or obstruct the sliding mechanisms.

Reference Information

Schematic Reference

Power Tonneau Cover Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Power Tonneau Cover Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Verification
  1. Place the transmitter on the test pad of the J 43241 Keyless Entry Tester and press each transmitter button one at a time. The tester should sound a tone and illuminate a green light with each button press.
    2. ⇒If one or more buttons does not sound the tone and illuminate the green light, replace the transmitter battery and retest with the J 43241 . If the condition continues after battery replacement, replace the transmitter
  2. Press the Exit/Learn switch located on the motor cover, left of the cargo bed light. The cargo bed light should illuminate.
  3. Press the key fob cargo bed light button. The cargo bed light should turn off.
  4. Perform the Power Tonneau Cover Initialization procedure. Refer to Power Tonneau Cover Initialization.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the receiver module.
  2. Test for less than 10 ohms between the ground circuit terminals 9 and 16 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Verify that a test lamp illuminates between the B+ circuit terminals 1 and 18 and ground.
    4. ⇒If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Connect the harness connector at the receiver module.
  5. Disconnect the harness connector at the master motor.
  6. Test for less than 10 ohms between the ground circuit terminal 2 and ground.
    7. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Verify that a test lamp illuminates between the B+ circuit terminal 4 and ground.
    8. ⇒If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  8. Connect a test lamp between the wake up signal circuit terminal 5 and ground.
  9. Press the key fob open button. The test lamp should illuminate.
    10. ⇒If the test lamp does not illuminate, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the receiver module.
  10. Connect a test lamp between B+ and the open signal circuit terminal 11.
  11. Press the key fob open button. The test lamp should illuminate.
    12. ⇒If the test lamp does not illuminate, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the receiver module.
  12. Connect a test lamp between B+ and the close signal circuit terminal 12.
  13. Press the key fob close button. The test lamp should illuminate.
    14. ⇒If the test lamp does not illuminate, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the receiver module.
  14. Disconnect the harness connector at the slave motor.
  15. Test for less than 10 ohms between the ground circuit terminal 9 and ground.
    16. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  16. Verify that a test lamp illuminates between the B+ circuit terminal 5 and ground.
    17. ⇒If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  17. Test for less than 2 ohms between the master motor X Bus circuit terminal 6 and slave motor X Bus circuit terminal 1.
  18. If all circuits test normal replace the master and slave motors.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.