DTC U1281: Auto Light Control Unit Lost Communication with MICU; DTC U128D: Auto Light Control Unit Lost Communication with Gauge Control Module (Automatic Lighting Control Unit) (2018-19)
NOTE:
- 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.
- If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A - Refer to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks, or Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks (2018-19) .
| DTC Description | DTC |
|---|---|
| U1281 Auto Light Control Unit Lost Communication with MICU | |
| U128D Auto Light Control Unit Lost Communication with Gauge Control Module |
DTC (Automatic Lighting Control Unit)
- Problem verification
-1. Turn the vehicle to the ON mode.
- 2. Clear the DTC with the HDS.
- 3. Turn the vehicle to the OFF (LOCK) mode and then the ON mode.
- 4. Wait for at least 6 seconds.
- 5. Check for DTCs with the HDS.
DTC Description DTC U1281 Auto Light Control Unit Lost Communication with MICU 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. Disconnect the transmitting control unit connector (s).
Refer to the DTC shown on the display, then disconnect the connector (s) based on the instructions (see table).
DTC Connector U1281 Under-dash fuse/relay box connector M (12P) U128D Gauge control module 32P connector - 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: disconnected
DTC 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 Under-dash fuse/relay box connector M (12P) - Refer to: Under-Dash Fuse/Relay Box Connector for Inputs and Outputs, or Under-Dash Fuse/Relay Box Connector for Inputs and Outputs (With SH-AWD), or Under-Dash Fuse/Relay Box Connector for Inputs and Outputs (2018-19) No. 4 B-CAN_L No. 2 No. 5 U128D B-CAN_H Automatic lighting control unit-sensor 5P connector No. 1 Under-dash fuse/relay box connector M (12P) - Refer to: Under-Dash Fuse/Relay Box Connector for Inputs and Outputs, or Under-Dash Fuse/Relay Box Connector for Inputs and Outputs (With SH-AWD), or Under-Dash Fuse/Relay Box Connector for Inputs and Outputs (2018-19) No. 25 B-CAN_L No. 2 No. 26 Is there continuity?
YES
The B-CAN_H wire and the B-CAN_L wire are OK.Refer to the DTC shown on the display, then substitute or replace the control unit based on the instructions (see table).
DTC Operation for transmitting control unit U1281 Substitute a known-good under-dash fuse/relay box , then recheck. If DTC U1281 goes away after substitution, replace the original under-dash fuse/relay box . 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.