DTC Troubleshooting: U1281, U128D (Automatic Lighting/Rain Sensor)

DTC Troubleshooting: U1281, U128D

DTC U1281: Rain Light Sensor Unit Lost Communication with MICU (Body Control Module)
DTC U128D: Rain Light Sensor Unit Lost Communication with Gauge Control Module

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/rain 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.

DTC Description	DTC
U1281 Rain Light Sensor Unit Lost Communication with MICU (Body Control Module)
U128D Rain Light Sensor Unit Lost Communication with Gauge Control Module

Problem verification:

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 Rain Light Sensor Unit Lost Communication with MICU (Body Control Module)
U128D Rain Light Sensor 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/rain sensor.?

Open wire check (B-CAN_H line, B-CAN_L line):

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/rain 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	Body control module connector B (36P)
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/rain sensor 5P connector: disconnected
Transmitting control unit connector(s) for indicated DTCs: disconnected

DTC	Circuit name	Receiving control unit		Transmitting control unit
DTC	Circuit name	Connector	Terminal	Connector	Terminal
U1281	B-CAN_H	Automatic lighting/rain sensor 5P connector	No. 4	Body control module connector B (36P)	No. 20
U1281	B-CAN_L	Automatic lighting/rain sensor 5P connector	No. 3	Body control module connector B (36P)	No. 21
U128D	B-CAN_H	Automatic lighting/rain sensor 5P connector	No. 4	Gauge control module connector A (32P)	No. 30
U128D	B-CAN_L	Automatic lighting/rain sensor 5P connector	No. 3	Gauge control module connector A (32P)	No. 31

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 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/rain sensor and the transmitting control unit.?