Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Pinpoint Test F: The Vehicle Dynamics Module (VDM) Does Not Respond To The Scan Tool
Refer to appropriate SYSTEM WIRING DIAGRAMS article, Module Communications Network for schematic and connector information.
Refer to appropriate SYSTEM WIRING DIAGRAMS article, Vehicle Dynamic Suspension for schematic and connector information.
Normal Operation
The vehicle dynamics module (VDM) (if equipped) communicates with the scan tool through the high speed controller area network (HS-CAN). Circuits 1827 (WH/LG) (HS-CAN +) and 1828 (PK/LG) (HS-CAN -) provide the network connection to the VDM. The VDM shares the HS-CAN with the PCM, the ABS module and the instrument cluster (IC). Voltage for the VDM is provided by circuits 418 (DG/YE) and 1003 (GY/YE). Circuit 57 (BK) provides ground.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- VDM
PINPOINT TEST F: THE VEHICLE DYNAMICS MODULE (VDM) DOES NOT RESPOND TO THE SCAN TOOL
- F1 CHECK THE VDM VOLTAGE SUPPLY CIRCUITS FOR AN OPEN
- Key in OFF position.
- Disconnect: VDM C2131a
- Key in ON position.
- Measure the voltage between the VDM, harness side and ground as follows:
Connector-Pin Circuit C2131a-11 418 (DG/YE) C2131a-12 418 (DG/YE) C2131a-3 1003 (GY/YE) - Are the voltages greater than 10 volts?
- YES : Go to F2.
- NO : VERIFY the battery junction box (BJB) fuse 5 (10A) and the central junction box (CJB) fuse 13 (10A) is OK. If OK, REPAIR the circuit in question. CLEAR the DTCs. REPEAT the network test with the scan tool.
- F2 CHECK THE VDM GROUND CIRCUITS FOR AN OPEN
- Key in OFF position.
- Disconnect: VDM C2131b
- Measure the resistance between the VDM, harness side and ground as follows:
Connector-Pin Circuit C2131a-5 57 (BK) C2131a-14 57 (BK) - Are the resistances less than 5 ohms?
- YES : Go to F3.
- NO : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the network test with the scan tool.
- F3 CHECK THE HS-CAN CIRCUITS BETWEEN THE DATA LINK CONNECTOR (DLC) AND THE VDM FOR AN OPEN
- Measure the resistance between the VDM C2131a-10, circuit 1827 (WH/LG), harness side and the DLC C251-6, circuit 1827 (WH/LG), harness side.
- Measure the resistance between the VDM C2131a-9, circuit 1828 (PK/LG), harness side and the DLC C251-14, circuit 1828 (PK/LG) harness side.
- Are the resistances less than 5 ohms?
- YES : Go to F4.
- NO : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the network test with the scan tool.
- F4 CHECK FOR CORRECT VDM OPERATION
- Disconnect all the VDM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the VDM 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 VDM. REFER to VEHICLE DYNAMIC SUSPENSION article. 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. CLEAR the DTCs. REPEAT the network test with the scan tool.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.