Toyota Tundra Service Manual: Lost Communication with "Seat Control Module A" (U0208)

Toyota Tundra Service Manual / Power Source, Network / Can Communication / Can Communication System / Lost Communication with "Seat Control Module A" (U0208)

DESCRIPTION

DTC No.

DTC Detection Condition

Trouble Area

U0208

There is no communication from the front power seat switch LH (power seat control ECU).

  • Front power seat switch LH (power seat control ECU) CAN branch wire or connector
  • Power source or inside of front power seat switch LH (power seat control ECU)
  • Front power seat switch LH (power seat control ECU) ground circuit
  • Front power seat switch LH (power seat control ECU)

WIRING DIAGRAM

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

NOTICE:

  • Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.

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  • Before measuring the resistance of the CAN bus, turn the ignition switch off and leave the vehicle for 1 minute or more without operating the key, switches or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
  • After turning the ignition switch off, waiting time may be required before disconnecting the cable from the battery terminal. Therefore, make sure to read the disconnecting the cable from the battery terminal notice before proceeding with work.

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  • Some parts must be initialized and set when replacing or removing and installing parts.

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  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

    DTC check procedure: Turn the ignition switch to ON, wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.

  • After the repair, perform CAN Bus Check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.

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  • Inspect the fuses for circuits related to this system before performing the following procedure.

HINT:

  • Operating the ignition switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.
  • Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE

1.

PRECAUTION

(a) Reconfirm DTCs.

HINT:

If DTC U1002 is output from Gateway 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).

A

DTC U1002 is output from main body ECU (multiplex network body ECU).

B

B

GO TO DIAGNOSIS PROCEDURE INDICATED BY OUTPUT DTC

A

2.

CHECK FOR OPEN IN CAN BUS WIRE (FRONT POWER SEAT SWITCH LH [Power Seat Control ECU] CAN BRANCH WIRE)

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

(b) Disconnect the front power seat switch LH (power seat control ECU) connector.

*a

Front view of wire harness connector

(to Front Power Seat Switch LH [Power Seat Control ECU])

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Z10-8 (CANH) - Z10-7 (CANL)

Cable disconnected from negative (-) battery terminal

54 to 69 Ω

NG

REPAIR OR REPLACE FRONT POWER SEAT SWITCH LH CAN BRANCH WIRE OR CONNECTOR

OK

3.

CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

(a) Disconnect the front power seat switch LH (power seat control ECU) connector.

*a

Front view of wire harness connector

(to Front Power Seat Switch [Power Seat Control ECU])

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Z9-2 (GND1) - Body ground

Cable disconnected from negative (-) battery terminal

Below 1 Ω

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

NOTICE:

When disconnecting the cable, some systems need to be initialized after the cable is reconnected.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

Z9-6 (+B1) - Body ground

Always

11 to 14 V

Z10-12 (SYSB) - Body ground

Always

11 to 14 V

OK

REPLACE FRONT POWER SEAT SWITCH LH (POWER SEAT CONTROL ECU)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    Lost Communication with "Door Control Module B" (U0200)

    Lost Communication with Gateway Module (U1002)

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