Pinpoint Test G: DTCs B2741, C2777, C2778 And U1901
Anti-Lock Control
Pinpoint Tests
Pinpoint Test G: DTCs B2741, C2777, C2778 and U1901
Refer to Wiring Diagram Set 42, Vehicle Dynamic Systems for schematic and connector information. Diagrams By Number
Normal Operation
The yaw rate sensor, roll rate sensor, lateral accelerometer and longitudinal accelerometer are contained in one module called the stability control sensor cluster. The sensor cluster measures the vehicle acceleration, roll rate and yaw rate, then sends the signal along a dedicated Controller Area Network (CAN) bus to the ABS module.
Voltage is supplied from the ABS module to the sensor cluster along circuit CCA09 (VT/BN) and ground is provided through the ABS module along circuit RCA09 (GN/VT). Circuits VCA23 (BU/WH) and VCA24 (GN/OG) make up the dedicated CAN bus between the ABS module and the sensor cluster.
DTC B2741 / DTC C2777-DTC C2778 / DTC U1901:
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Stability control sensor cluster
- ABS module
PINPOINT TEST G: DTCs B2741, C2777, C2778 and U1901
NOTICE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.
NOTE: The vehicle must be on level ground, not on a hoist and at a complete standstill. Any vehicle movement will result in false values for this test.
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G1 CHECK FOR ABS MODULE DTCs
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Clear All CMDTCs.
- Drive the vehicle in a straight line at a speed greater than 40 km/h (25 mph) for at least 60 seconds.
- Enter the following diagnostic mode on the scan tool: Self Test - ABS Module .
- Retrieve and record any ABS module DTCs.
- Is DTC B2741, C2777, C2778 or U1901 present?
Yes
GO to G2.
No
The concern is not present at this time. INSPECT the sensor cluster for damage. VERIFY that the sensor cluster is mounted properly. REPAIR or INSTALL new as necessary. TEST the system for normal operation.
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G2 CHECK FOR VOLTAGE TO THE SENSOR CLUSTER
NOTE: Turning the ignition ON with C3073 disconnected will cause additional DTCs to set in the ABS module.
- Ignition OFF.
- Disconnect: Sensor Cluster C3073.
- Ignition ON.
- Measure the voltage between sensor cluster C3073-3, circuit CCA09 (VT/BN), harness side and sensor cluster C3073-5, circuit RCA09 (GN/VT), harness side.
- Is the voltage between 7.5 volts and 17 volts?
Yes
If DTC B2741 was retrieved from the self-test, GO to G10.
If DTC C2777, U1901 or C2778 were retrieved from the self-test, GO to G4.
No
GO to G3.
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G3 CHECK THE SENSOR CLUSTER POWER AND GROUND CIRCUITS FOR AN OPEN
- Ignition OFF.
- Disconnect: ABS Module C155.
- Measure the resistance between the ABS module connector, harness side and the sensor cluster connector, harness side as indicated in the following chart:
- Is the resistance less than 5 ohms?
Yes
GO to G8.
No
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.
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G4 CHECK THE DEDICATED CAN BUS CIRCUITS FOR AN OPEN
- Disconnect: ABS Module C155.
- Measure the resistance between the ABS module connector, harness side and the sensor cluster connector, harness side as indicated in the following chart:
- Is the resistance less than 5 ohms?
Yes
GO to G5.
No
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.
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G5 CHECK THE DEDICATED CAN BUS CIRCUITS FOR A SHORT TOGETHER
- Measure the resistance between sensor cluster connection C3073-2, circuit VCA23 (BU/WH), harness side and C3073-1, circuit VCA24 (GN/OG), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to G6.
No
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.
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G6 CHECK THE DEDICATED CAN BUS TERMINATING RESISTANCE
- Connect: ABS Module C155.
- Measure the resistance between sensor cluster connection C3073-2, circuit VCA23 (BU/WH), harness side and C3073-1, circuit VCA24 (GN/OG), harness side.
- Is the resistance approximately 120 ohms?
Yes
GO to G7.
No
GO to G11.
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G7 CHECK THE DEDICATED CAN BUS VOLTAGE
- Ignition ON.
- Measure the voltage between ground and:
- sensor cluster connection C3073-2, circuit VCA23 (BU/WH), harness side.
- sensor cluster connection C3073-1, circuit VCA24 (GN/OG), harness side.
- Is the voltage between 1 and 3 volts?
Yes
GO to G10.
No
GO to G8.
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G8 CHECK THE SENSOR CLUSTER CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ABS Module C155.
- Ignition ON.
- Measure the voltage between ground and:
- sensor cluster C3073-1, circuit VCA24 (GN/OG), harness side.
- sensor cluster C3073-2, circuit VCA23 (BU/WH), harness side.
- sensor cluster C3073-3, circuit CCA09 (VT/BN), harness side.
- sensor cluster C3073-5, circuit RCA09 (GN/VT), harness side.
- Is any voltage present?
Yes
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.
No
GO to G9.
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G9 CHECK THE SENSOR CLUSTER CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between ground and:
- sensor cluster C3073-1, circuit VCA24 (GN/OG), harness side.
- sensor cluster C3073-2, circuit VCA23 (BU/WH), harness side.
- sensor cluster C3073-3, circuit CCA09 (VT/BN), harness side.
- sensor cluster C3073-5, circuit RCA09 (GN/VT), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to G11.
No
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.
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G10 CHECK THE SENSOR CLUSTER ELECTRICAL CONNECTION
- Check sensor cluster C3073 for:
- corrosion.
- pushed-out pins.
- spread terminals.
- Connect: Sensor Cluster C3073.
- Make sure the connector seats correctly, clear all ABS module DTCs, then operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new sensor cluster. REFER to Stability Control Sensor Cluster Service and Repair. TEST the system for normal operation.
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 self-test.
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G11 CHECK FOR CORRECT ABS MODULE OPERATION
- Check ABS module C155 for:
- corrosion.
- pushed-out pins.
- spread terminals.
- Connect: ABS Module C155.
- Make sure the connector seats correctly, clear all ABS module DTCs, then operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module Service and Repair. TEST the system for normal operation.
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 self-test.
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