U0125-00 - Lost Communication With Multi - Axis Acceleration Sensor Module

For a complete wiring diagram, refer to appropriate Wiring Diagram.

>>When Monitored:<< With the ignition on.
>>Set Condition:<< If the Anti-lock Brakes System (ABS) Module fails to receive bus messages from the Dynamics Sensor.

Possible Causes
WIRING HARNESS, TERMINAL, CONNECTOR DAMAGE
(F941) FUSED IGNITION SWITCH OUTPUT (RUN/START) CIRCUIT OPEN OR HIGH RESISTANCE
(Z909) GROUND CIRCUIT OPEN OR HIGH RESISTANCE
(D465) DYNAMICS SENSOR HIGH DATA LINK CIRCUIT OPEN
(D464) DYNAMICS SENSOR LOW DATA LINK CIRCUIT SHORTED TO VOLTAGE
(D464) DYNAMICS SENSOR LOW DATA LINK CIRCUIT SHORTED TO GROUND
(D464) DYNAMICS SENSOR LOW DATA LINK CIRCUIT OPEN
(D464) DYNAMICS SENSOR LOW DATA LINK CIRCUIT SHORTED TO THE (D465) DYNAMICS SENSOR HIGH DATA LINK CIRCUIT
DYNAMICS SENSOR

Test Step 1 - VERIFY THE DTC IS ACTIVE

NOTE:

If DTC C2114-16, C2114-17 or U1003-88 are present, perform the diagnostics for these DTCs before continuing with this diagnostic procedure.

Turn the ignition on.
Using the scan tool, read and record ABS DTCs.
Using the scan tool, read and record Environmental Data (EV Data).
Using the scan tool, erase ABS DTCs.
Cycle the ignition switch.
Using the scan tool, read ABS DTCs.

Is the DTC active at this time?

Yes

Go to Test Step 2

Perform the ABS Intermittent Condition Test. Refer to Brake System

Test Step 2 - INSPECT RELATED WIRING HARNESS, TERMINALS, AND CONNECTORS

Turn the ignition off to the lock position.

WARNING:

To avoid serious or fatal injury on vehicles equipped with airbags, disable the Supplemental Restraint System (SRS) before attempting any steering wheel, steering column, airbag, seat belt tensioner, impact sensor, or instrument panel component diagnosis or service. Disconnect and isolate the battery negative (ground) cable, then wait two minutes for the system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the SRS. Failure to take the proper precautions could result in accidental airbag deployment.

NOTE:

Proper Steering Angle Sensor installation is crucial for proper operation.

Visually inspect the related wiring harness. Look for any pinched, chafed, pierced, and partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, and corroded terminals.

Were any problems found?

Yes

Repair as necessary.
Perform the ABS Verification Test. Refer to Brake System .

Go to Test Step 3

Test Step 3 - CHECK THE (F941) FUSED IGNITION SWITCH OUTPUT (RUN/START) CIRCUIT FOR AN OPEN OR HIGH RESISTANCE

Disconnect the ABS Module harness connector.
Disconnect the Dynamics Sensor harness connector.
Measure the resistance of the (F941) Fused Ignition Switch Output circuit between the Dynamics Sensor harness connector and the Anti-Lock Brakes Module harness connector.

Is the resistance below 5.0 Ohms?

Yes

Go to Test Step 4

Repair the (F941) Fused Ignition Switch Output circuit for an open.
Perform the ABS Verification Test. Refer to Brake System .

Test Step 4 - (Z909) GROUND CIRCUIT OPEN OR HIGH RESISTANCE

Using a 12-volt test light connected to B+, check the (Z909) Ground circuit at the Dynamics Sensor harness connector.

NOTE:

The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.

Does the test light illuminate brightly?

Yes

Go to Test Step 5

Repair the (Z909) Ground circuit for an open or high resistance.
Perform the ABS Verification Test. Refer to Brake System .

Test Step 5 - CHECK THE (D465) DYNAMICS SENSOR HIGH DATA LINK CIRCUIT FOR A SHORT TO VOLTAGE

Turn the ignition on.
Measure the voltage of the (D465) Dynamics Sensor High Data Link circuit.

Is there any voltage present?

Yes

Repair the (D465) Dynamics Sensor High Data Link circuit for a short to voltage.
Perform the ABS Verification Test. Refer to Brake System .

Go to Test Step 6

Test Step 6 - CHECK THE (D465) DYNAMICS SENSOR HIGH DATA LINK CIRCUIT FOR A SHORT TO GROUND

Turn the ignition off.
Measure the resistance of the (D465) Dynamics Sensor High Data Link circuit between ground and the Dynamics Sensor harness connector.

Is the resistance below 5.0 Ohms?

Yes

Repair the (D465) Dynamics Sensor High Data Link circuit for a short to ground.
Perform the ABS Verification Test. Refer to Brake System .

Go to Test Step 7

Test Step 7 - CHECK THE (D465) DYNAMICS SENSOR HIGH DATA LINK CIRCUIT FOR AN OPEN

Measure the resistance of the (D465) Dynamics Sensor High Data Link circuit between the Dynamics Sensor harness connector and the Anti-Lock Brakes Module harness connector.

Is the resistance below 5.0 Ohms?

Yes

Go to Test Step 8

Repair the (D465) Dynamics Sensor High Data Link circuit for an open.
Perform the ABS Verification Test. Refer to Brake System .

Test Step 8 - CHECK THE (D464) DYNAMICS SENSOR LOW DATA LINK CIRCUIT FOR A SHORT TO VOLTAGE

Turn the ignition on.
Measure the voltage of the (D464) Dynamics Sensor Low Data Link circuit.

Is there any voltage present?

Yes

Repair the (D464) Dynamics Sensor Low Data Link circuit for a short to voltage.
Perform the ABS Verification Test. Refer to Brake System .

Go to Test Step 9

Test Step 9 - CHECK THE (D464) DYNAMICS SENSOR LOW DATA LINK CIRCUIT FOR A SHORT TO GROUND

Turn the ignition off.
Measure the resistance of the (D464) Dynamics Sensor Low Data Link circuit between ground and the Dynamics Sensor harness connector.

Is the resistance below 5.0 Ohms?

Yes

Repair the (D464) Dynamics Sensor Low Data Link circuit for a short to ground.
Perform the ABS Verification Test. Refer to Brake System .

Go to Test Step 10

Test Step 10 - CHECK THE (D464) DYNAMICS SENSOR LOW DATA LINK CIRCUIT FOR AN OPEN

Measure the resistance of the (D464) Dynamics Sensor Low Data Link circuit between the Dynamics Sensor harness connector and the ABS Module harness connector.

Is the resistance below 5.0 Ohms?

Yes

Go to Test Step 11

Repair the (D464) Dynamics Sensor Low Data Link circuit for an open.
Perform the ABS Verification Test. Refer to Brake System .

Test Step 11 - (D465) DYNAMICS SENSOR HIGH DATA LINK CIRCUIT SHORTED TO THE (D464) DYNAMICS SENSOR LOW DATA LINK CIRCUIT

Turn the ignition off.
Measure the resistance between the (D465) Dynamics Sensor High Data Link circuit and the (D464) Dynamics Sensor Low Data Link circuit at the ABS Module harness connector.

Is the resistance below 5.0 Ohms?

Yes

Repair the (D464) Dynamics Sensor Low Data Link circuit for a short to (D465) Dynamics Sensor High Data Link circuit.
Perform the ABS Verification Test. Refer to Brake System .

Go to Test Step 12

Test Step 12 - CHECK FOR DTC U0125-00-LOST COMMUNICATION WITH MULTI-AXIS ACCELERATION SENSOR MODULE

Replace the Dynamics Sensor. Refer to Removal and Installation .
Perform the ABS Verification Test. Refer to Brake System .
Turn the ignition on.
With the scan tool, record and erase DTCs.
Cycle the ignition switch from off to on.
With the scan tool, read DTCs.

Does the DTC remain active?

Yes

Replace the Anti-lock Brake System (ABS) Module. Refer to Removal and Installation .
Perform the ABS Verification Test. Refer to Brake System .

Test complete.