DTC U0208: Lost Communication with "Seat Control Module A" [10/2015 - ]: Procedure

1. 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 sub bus 1.

   Result

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

Result: 

B 

GO TO DIAGNOSTIC PROCEDURE INDICATED BY OUTPUT DTC. Refer to  DTC U1002: Lost Communication with Gateway Module (Main Body ECU) [10/2015 - ]  

Result: 

A 

See step  2

1. Disconnect the cable from the negative (-) auxiliary battery terminal.
2. Disconnect the S9 front power seat switch LH connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   S9-8 (CANP) - S9-7 (CANN)	Cable disconnected from negative (-) auxiliary battery terminal	54 to 69 Ω

   Result

   Result
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (FRONT POWER SEAT SWITCH LH BRANCH LINES) 

Result: 

OK 

See step  3

1. Disconnect the S8 front power seat switch LH connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   S8-2 (GND) - Body ground	Cable disconnected from negative (-) auxiliary battery terminal	Below 1 Ω

3. Reconnect the cable to the negative (-) auxiliary battery terminal.
4. Measure the voltage according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   S8-7 (+B) - Body ground	Power switch off	11 to 14 V
   S9-12 (SYSB) - Body ground	Power switch off	11 to 14 V

   Result

   Result
   OK
   NG

Result: 

OK 

REPLACE FRONT POWER SEAT SWITCH LH. Refer to  REMOVAL [10/2014 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)