Pinpoint Test B: The ABS Module Does Not Respond To The Scan Tool
Communications Network
Pinpoint Tests
Pinpoint Test B: The ABS Module Does Not Respond To The Scan Tool
Refer to Wiring Diagrams Set 14, Module Communications Network for schematic and connector information. Diagrams By Number
Refer to Wiring Diagrams Set 42, Vehicle Dynamic Systems for schematic and connector information. Diagrams By Number
Normal Operation
The ABS module 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 ABS module. Voltage for the ABS module is provided by circuits SBB18 (YE/RD), SBB09 (RD) and CBP31 (BU/OG). Ground is provided by circuit GD122 (BK).
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- ABS module
PINPOINT TEST B: THE ABS MODULE DOES NOT RESPOND TO THE SCAN TOOL
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.
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B1 CHECK THE ABS MODULE VOLTAGE SUPPLY CIRCUITS FOR AN OPEN
- Ignition OFF.
- Disconnect: ABS Module C135 (Without Stability Control) or C155 (With Stability Control).
- Ignition ON.
- Measure the voltage between the ABS module, harness side and ground as follows:
- Are the voltages greater than 10 volts?
Yes
GO to B2.
No
VERIFY the Battery Junction Box (BJB) fuses 18 (20A), 9 (40A) and the Smart Junction Box (SJB) fuse 31 (10A) are OK. If OK, REPAIR the circuit in question. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the network test with the scan tool.
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B2 CHECK THE ABS MODULE GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- For vehicles without stability control, measure the resistance between the ABS module C135-26, circuit GD122 (BK), harness side and ground.
- For vehicles with stability control, measure the resistance between the ABS module C155-16, circuit GD122 (BK), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to B3.
No
REPAIR the circuit. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
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B3 CHECK THE HS-CAN CIRCUITS BETWEEN THE ABS MODULE AND THE DLC FOR AN OPEN
- For vehicles without stability control, measure the resistance between the ABS module C135-23, circuit VDB04 (WH/BU), harness side and the Data Link Connector (DLC) C251-6, circuit VDB04 (WH/BU), harness side.
- For vehicles without stability control, measure the resistance between the ABS module C135-21, circuit VDB05 (WH), harness side and the DLC C251-14, circuit VDB05 (WH), harness side.
- For vehicles with stability control, measure the resistance between the ABS module C155-12, circuit VDB04 (WH/BU), harness side and the DLC C251-6, circuit VDB04 (WH/BU), harness side.
- For vehicles with stability control, measure the resistance between the ABS module C155-13, 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 B4.
No
REPAIR the circuit in question. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
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B4 CHECK FOR CORRECT ABS MODULE OPERATION
- Disconnect the ABS module connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the ABS module connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new ABS module. 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.
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