DTC U0208: Lost Communication with "Seat Control Module A" [08/2013 - ]: Procedure

WARNING: This page is about a different car, the 2014 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.

RECONFIRM DTC OUTPUT

Reconfirm DTCs.

HINT:

If DTC U1002 is output from Main Body of the main body ECU (multiplex network body ECU), this indicates a sub bus 1 malfunction. Troubleshoot for DTC U1002 and check for malfunctions in the sub bus 1.

Result

Result	Proceed to
U1002 is not output from main body ECU (multiplex network body ECU) (Techstream display: Main Body)	A
U1002 is output from main body ECU (multiplex network body ECU) (Techstream display: Main Body)	B

B → See step 5

A: Go to next step

CHECK FOR OPEN IN SUB BUS 1 LINES (FRONT POWER SEAT SWITCH LH BRANCH LINE)

Disconnect the cable from the negative (-) auxiliary battery terminal.

Disconnect the X10 front power seat switch LH connector.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
X10-8 (CANP) - X10-7 (CANN)	Cable disconnected from negative (-) auxiliary battery terminal	54 to 69 Ω

TEXT IN ILLUSTRATION

*a	Front view of wire harness connector (to Front Power Seat Switch LH)

NG → REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (FRONT POWER SEAT SWITCH LH)

OK: Go to next step

CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

Disconnect the X9 front power seat switch LH connector.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
X9-2 (GND) - Body ground	Cable disconnected from negative (-) auxiliary battery terminal	Below 1 Ω

Reconnect the cable to the negative (-) auxiliary battery terminal.

Measure the voltage according to the value(s) in the table below.

Standard Voltage

Tester Connection	Condition	Specified Condition
X9-7 (+B) - Body ground	Power switch off	11 to 14 V
X10-12 (SYSB) - Body ground	Power switch off	11 to 14 V

TEXT IN ILLUSTRATION

*a	Front view of wire harness connector (to Front Power Seat Switch LH)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

OK → See step 4

REPLACE FRONT POWER SEAT SWITCH LH. Refer to REMOVAL [08/2013 - ]
GO TO DIAGNOSIS PROCEDURE INDICATED BY OUTPUT DTC. Refer to DTC U1002: Lost Communication with Gateway Module (Main Body ECU) [08/2013 - ]