DTC U1281, U128D (Automatic Lighting Control Unit)
DTC U1281 : Auto Light Control Unit Lost Communication with MICU (Body Control Module)
DTC U128D : Auto Light Control Unit Lost Communication with Gauge Control Module
- If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A .
- According to the detected DTC(s), check for the power circuit and the ground circuit of the control unit which cannot communicate with the automatic lighting control unit-sensor.
- Refer to the DTC shown on the display, then inspect the connectors and terminals based on the instructions.
| DTC Description | DTC |
|---|---|
| U1281 Auto light control unit lost communication with MICU (body control module) | |
| U128D Auto light control unit lost communication with gauge control module |
DTC (Automatic Lighting Control Unit)
- Problem verification
-1. Clear the DTC with the HDS.
-2. Turn the vehicle to the OFF (LOCK) mode and then the ON mode.
-3. Wait for at least 6 seconds.
-4. Check for DTCs with the HDS.
DTC Description DTC U1281 Auto light control unit lost communication with MICU (body control module) U128D Auto light control unit lost communication with gauge control module Are any DTCs indicated?
YES
Go to step 2.
NO
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the transmitting control units and the automatic lighting control unit-sensor.
- Open wire check (B-CAN_H line, B-CAN_L line)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Disconnect the receiving control unit connector.
Automatic lighting control unit-sensor 5P connector -3. According to the detected DTC on the following table, disconnect the transmitting control unit connector(s).
DTC Connector U1281 Body control module connector A (66P) U128D Gauge control module connector A (32P) -4. Check for continuity between the receiving control unit and the transmitting control unit on the B-CAN_H circuit and the B-CAN_L circuit.
Test condition Vehicle OFF (LOCK) mode
Automatic lighting control unit-sensor 5P connector: disconnected
Transmitting control unit connector(s) for indicated DTCs: disconnectedDTC Circuit name Receiving control unit Transmitting control unit Connector Terminal Connector Terminal U1281 B-CAN_H Automatic lighting control unit-sensor 5P connector No. 1 Body control module connector A (66P) No. 54 B-CAN_L No. 2 No. 55 U128D B-CAN_H Automatic lighting control unit-sensor 5P connector No. 1 Gauge control module connector A (32P) No. 22 B-CAN_L No. 2 No. 23 Is there continuity?
YES
The B-CAN_H wire and the B-CAN_L wire are OK.
According to the detected DTC on the following table, substitute or replace the control unit based on the instructions (see table).
DTC Operation for transmitting control unit U1281 Substitute a known-good body control module , then recheck. If DTC U1281 goes away after substitution, replace the original body control module . U128D Substitute a known-good gauge control module , then recheck. If DTC U128D goes away after substitution, replace the original gauge control module . NO
Repair an open in the B-CAN_H wire and/or the B-CAN_L wire between the automatic lighting control unit-sensor and the transmitting control unit.