Steering Control Module (SCM)

U1008-00-LIN 1 BUS

For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The Right Steering Wheel Control Switch (Speed Control Switch) includes the cruise control functions. Cruise Control Functions are resistor multiplexed and are hard wired inputs to the Steering Angle Sensor (SAS) microprocessor. The switch also contains the circuitry of a Local Interface Network (LIN) slave node, which provides source current for and communicates the switch or sensor states of the Electronic Vehicle Information Center (EVIC) switches, the remote radio switches and the horn switch over the LIN data bus to the SAS, which is also the LIN master node and a gateway to the Controller Area Network (CAN) data bus. Speed Control Switch - Operation.

- When Monitored:
Continuously with the ignition on.

- Set Condition:
This DTC will set if there is a loss of LIN Bus communication between the Steering Control Module (SCM) and the Multifunction Switch.





Diagnostic Test

1. CHECK FOR AN ACTIVE DTC

NOTE: Before proceeding with the diagnostic procedure, verify that the connections are properly made, seated and verify proper pin terminal tension. A loose connection at any of the SCCM connectors may cause the DTC to set.

1. Turn the ignition on.
2. With the scan tool, read DTCs

Does the scan tool display this DTC as active?

Yes

- Go To 2

No

- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.

2. (A929) FUSED B+ CIRCUIT OPEN OR SHORTED TO GROUND
1. Turn the ignition off.
2. Disconnect the Multifunction Switch (SCM C2) harness connector.
3. Measure the voltage of the (A929) Fused B+ circuit at the Multifunction Switch (SCM C2) harness connector.

Is battery voltage present?

Yes

- Go To 3

No

- Repair the open in the (A929) Fused B+ circuit. Inspect the related fuse. If the fuse is open, check the circuit for a short to ground.
- Perform the BODY VERIFICATION TEST. Body Verification Test .

3. (F944) RUN/START RELAY OUTPUT CIRCUIT OPEN OR SHORTED TO GROUND
1. Turn the ignition on.
2. Measure the voltage of the (F944) Run/Start Relay Output circuit at the Multifunction Switch (SCM C2) harness connector.

Is battery voltage present?

Yes

- Go To 4

No

- Repair the open in the (F944) Fused Run/Start Relay Output circuit. Inspect the related fuse. If the fuse is open, check the circuit for a short to ground.
- Perform the BODY VERIFICATION TEST. Body Verification Test .

4. (Z926) GROUND CIRCUIT OPEN
1. Turn the ignition off.
2. Measure the resistance between ground and the (Z926) Ground circuit at the Multifunction Switch (SCM C2) harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 5

No

- Repair the open in the (Z926) Ground circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test .

5. (D506) LIN BUS CIRCUIT OPEN OR SHORTED TO GROUND
1. Turn the ignition on.
2. Measure the voltage of the (D506) LIN Bus circuit at the Multifunction Switch (SCM C2) harness connector.

Is voltage present?

Yes

- Replace the Multifunction Switch. Multifunction Switch - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test .

No

- Repair the open in the (D506) LIN Bus circuit between the Multifunction Switch (SCM C2) and SCM C4 harness connectors.
- Perform the BODY VERIFICATION TEST. Body Verification Test .