Pinpoint Test D: The Restraints Control Module (RCM) Does Not Respond to the Scan Tool

Communications Network

Pinpoint Tests

Pinpoint Test D: The Restraints Control Module (RCM) Does Not Respond To The Scan Tool

Refer to Wiring Diagram Set 14, Module Communications Network for schematic and connector information. Diagrams By Number

Refer to Wiring Diagram Set 46, Supplemental Restraint System for schematic and connector information. Diagrams By Number

Normal Operation

The Restraints Control Module (RCM) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN). Circuits VDB04 (WH/BU) (HS-CAN +) and VDB05 (WH) (HS-CAN -) provide the network connection to the RCM. Voltage for the RCM is provided by circuit CBP21 (BU/GY), and the RCM is case grounded.

This pinpoint test is intended to diagnose the following:

- Fuse
- Wiring, terminals or connectors
- Case ground open
- RCM



PINPOINT TEST D: THE RCM DOES NOT RESPOND TO THE SCAN TOOL

WARNING: Never probe the electrical connectors on air bag, safety canopy or side air curtain modules. Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.

WARNING: Never probe the electrical connectors on safety belt buckle/retractor pretensioners or adaptive load limiting retractors. Failure to follow this instruction may result in the accidental deployment of the safety belt pretensioners or adaptive load limiting retractors, which increases the risk of serious personal injury or death.

NOTE: The Supplemental Restraint System (SRS) must be fully operational and free of faults before releasing the vehicle to the customer.

NOTE: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.

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D1 CHECK THE RCM CONNECTION


- Ignition OFF.
- Depower the SRS. Refer to Air Bag Systems.
- Disconnect: RCM C310a.
- Disconnect: RCM C310b.
- Are RCM C310a pin 24, and RCM C310b pins 17 and 18 OK?

Yes
GO to D2.

No
REPAIR the RCM connector pins as necessary. REPOWER the SRS. REFER to Air Bag Systems. CLEAR the DTCs. REPEAT the network test with the scan tool.

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D2 CHECK THE RCM VOLTAGE SUPPLY CIRCUIT FOR AN OPEN


- Deactivate the SRS. Refer to Air Bag Systems.
- Repower the SRS. Refer to Air Bag Systems.
- Ignition ON.
- Measure the voltage between the RCM C310a-24, circuit CBP21 (BU/GY), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
GO to D3.

No
VERIFY the Smart Junction Box (SJB) fuse 25 (7.5A) is OK. If OK, REPAIR the circuit. REACTIVATE the SRS. REFER to Air Bag Systems. CLEAR the DTCs. REPEAT the network test with the scan tool. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.

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D3 CHECK THE RCM CASE GROUND


- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the RCM case and a good chassis ground.
- Is the resistance less than 5 ohms?

Yes
GO to D4.

No
REPAIR the RCM case ground as necessary. REACTIVATE the SRS. REFER to Air Bag Systems. CLEAR the DTCs. REPEAT the network test with the scan tool.

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D4 CHECK THE HS-CAN CIRCUITS BETWEEN THE RCM AND THE DLC FOR AN OPEN


- Measure the resistance between the RCM C310b-18, circuit VDB04 (WH/BU), harness side and the Data Link Connector (DLC) C251-6, circuit VDB04 (WH/BU), harness side.




- Measure the resistance between the RCM C310b-17, circuit VDB05 (WH), harness side and the DLC C251-14, circuit VDB05 (WH), harness side.




- Are the resistances less than 5 ohms?

Yes
CONNECT the negative battery cable. GO to D5.

No
REPAIR the circuit in question. REACTIVATE the SRS. REFER to Air Bag Systems. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.

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D5 CHECK FOR CORRECT RCM OPERATION


- Disconnect all the RCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the RCM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?

Yes
INSTALL a new RCM. REACTIVATE the SRS. REFER to Air Bag Systems. CLEAR the DTCs. REPEAT the network test with the scan tool.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. REACTIVATE the SRS. REFER to Air Bag Systems. CLEAR the DTCs. REPEAT the network test with the scan tool.

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