Pinpoint Test L: DTC U0101

Anti-Lock Control - Three-Channel

Pinpoint Tests

Pinpoint Test L: DTC U0101

Normal Operation
- DTC U0101 (Lost Communication With Transmission Control Module (TCM)) - sets in continuous and on-demand memory in the ABS module if data messages received, such as transmission range, from the Transmission Control Module (TCM) are missing for more than 5 seconds. For a complete list of all network messages, refer to Module Communications Network Testing and Inspection.

This pinpoint test is intended to diagnose the following:
- Communication network concern
- TCM
- ABS module

PINPOINT TEST L: DTC U0101

-------------------------------------------------
L1 VERIFY THE CUSTOMER CONCERN

- Ignition ON.
- Verify that there is an observable symptom present.
- Is an observable symptom present?

Yes
GO to L2.

No
The system is operating normally at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

-------------------------------------------------
L2 CHECK THE COMMUNICATION NETWORK

- Enter the following diagnostic mode on the scan tool: Network Test.
- Carry out the network test.
- Does the module pass the network test?

Yes
GO to L3.

No
REFER to Module Communications Network Testing and Inspection.

-------------------------------------------------
L3 RETRIEVE THE RECORDED DTCs FROM THE ABS MODULE SELF-TEST

- Check for recorded ABS DTCs from the self-test.
- Is DTC B1317 or DTC B1318 recorded?

Yes
For DTC B1317, GO to Pinpoint Test A. For DTC B1318, GO to Pinpoint Test B. Pinpoint Test A: DTC B1317 Pinpoint Test B: DTC B1318

No
GO to L4.

-------------------------------------------------
L4 RECHECK THE ABS MODULE DTCs

- Clear the DTCs.
- Wait 10 seconds.
- Repeat the ABS module self-test.
- Is DTC U0101 still present?

Yes
GO to L5.

No
The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

-------------------------------------------------
L5 CHECK FOR DTC U0101 SET IN OTHER MODULES

- Clear the DTCs.
- Ignition OFF.
- Ignition ON.
- Wait 10 seconds.
- Enter the following diagnostic mode on the scan tool: Self-Test.
- Retrieve the continuous memory DTCs from all modules.
- Is DTC U0101:00 or DTC U0101 set in more than one module?

Yes
INSTALL a new TCM (diesel engine) or PCM (gasoline engines). For PCM, REFER to Electronic Engine Controls - Gasoline Engines Service and Repair. CLEAR the DTCs. REPEAT the self-test.

No
INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module Service and Repair. TEST the system for normal operation.

-------------------------------------------------