No Response From HSM

NO RESPONSE FROM HSM





For complete wiring diagram refer to the wiring section.

POSSIBLE CAUSES
- (A940) fused B (+) circuit open or shorted
- (Z387) ground circuit open
- (D55) and (D54) CAN B bus circuits open
- Heated seat module

DIAGNOSTIC TEST

1. TEST FOR INTERMITTENT CONDITION
Turn the ignition on.

NOTE:
- Ensure the IOD fuse is installed and battery voltage is between 10.0 and 16.0 volts. With the scan tool, select ECU view.
- A red X will be next to the module that is not communicating, indicating that the module is not active on the Bus network. A green check indicates that the module is active on the Bus network.

Q: Does the scan tool display a red X next to the module?

YES: Go To 2
NO: The no response condition is not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring for chafed, pierced, pinched, and partially broken wires and the wiring harness connectors for broken, bent , pushed out, and corroded terminals.




2. (A940) FUSED B(+) CIRCUIT OPEN OR SHORTED
Turn the ignition off.
Disconnect the Heated Seat Module harness connector.
Using a 12-volt test light connected to ground, check the (A940) Fused B(+) circuit.

Q: Does the test light illuminate brightly?

YES: Go To 3
NO: Repair the (A940) Fused B(+) circuit for an open or short. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test




3. (Z387) GROUND CIRCUIT OPEN
Using a 12-volt test light connected to 12-volts, check the (Z387) ground circuit.

Q: Does the test light illuminate brightly?

YES: Go To 4
NO: Repair the (Z387) ground circuit for an open. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test




4. (D55) AND (D54) CAN B BUS CIRCUITS OPEN

NOTE: One open circuit will not cause this condition.

Measure the voltage between the (D54) CAN B Bus (-) circuit and ground.
Measure the voltage between the (D55) CAN B Bus (+) circuit and ground.

Q: Is there any voltage present on either circuit?

YES: Replace the Heated Seat Module in accordance with the service information. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Repair the (D55) and (D54) CAN B Bus circuits for an open. Inspect the connector for damage. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test