2007 Wrangler JK Factory Service Manual 5 - BRAKES

U1502-IMPLAUSIBLE MESSAGE DATA LENGTH RECEIVED FROM TCM

For a complete wiring diagram Refer to Section 8W

When Monitored:
Continuously, with ignition on.
Set Condition:
If the Anti-Lock Brakes Module detects bus messages from the Transmission Control Module (TCM) are of improper data length.

Possible Causes

WIRING HARNESS, TERMINAL, CONNECTOR DAMAGE

DTCs RELATED TO BATTERY VOLTAGE, IGNITION, OR VIN MESSAGES

CAN C BUS CIRCUITS OPEN OR SHORTED

TCM DTCs PRESENT

ANTI-LOCK BRAKES MODULE

Diagnostic Test

1. VERIFY DTC IS ACTIVE

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

Does this DTC reset?

Yes

Go To 2

No

The condition that caused the symptom is currently not present. Inspect the related wiring for a possible intermittent condition. Look for any chafed, pierced, pinched, or partially broken wires.
Refer to the ABS-INTERMITTENT CONDITION TEST. (Refer to 5 - BRAKES - DIAGNOSIS AND TESTING)

2. CHECK FOR ANY OF THE FOLLOWING ACTIVE DTCs

With the scan tool, read all active DTCs from all CAN C Bus modules.

NOTE: Check for CAN C hardware electrical, VIN Missing/Mismatch, battery or ignition related DTCs.

Does the scan tool display any active DTCs related to the conditions listed above?

Yes

Diagnose and repair the DTC(s). Refer to the Table of Contents in the applicable Section.

No

Go To 3

3. CHECK IF TCM DTCs ARE PRESENT

With the scan tool, read TCM DTCs.

Are any TCM DTCs present?

Yes

Diagnose and repair the DTC(s).
Perform TRANSMISSION VERIFICATION TEST - VER 1.

No

Using the schematics as a guide, check the Anti-Lock Brakes Module pins, terminals, and connectors for corrosion, damage, and terminal push out. Pay particular attention to all Communication circuits. If no problems are found, replace the Anti-Lock Brakes Module in accordance with the Service Information.

Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE).