DTC U0103: Lost Communication with Gear Shift Module "A": Procedure

1. Reconfirm DTCs.

   HINT: 

   If V2 bus DTC U1002 is output from the power management control ECU (Techstream display/PM1 Gateway), troubleshoot for U1002 and check for malfunctions in the V2 main bus circuit.

   Result

   Result	Proceed to
   U1002 is not output from power management control ECU (Techstream display/PM1 Gateway)	A
   U1002 is output from power management control ECU (Techstream display/PM1 Gateway)	B

B → See step   6 

A: Go to next step 

1. Disconnect the cable from the negative (-) auxiliary battery terminal.
2. Disconnect the transmission control ECU assembly connector.
   Fig 1: Identifying A24 Connector Terminal

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Switch Condition	Specified Condition
   A24-16 (CA1H) - A24-15 (CA1L)	Cable disconnected from negative (-) auxiliary battery terminal	54 to 69 Ω

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Transmission Control ECU Assembly)

NG → REPAIR OR REPLACE CAN MAIN BUS BRANCH WIRE OR CONNECTOR (TRANSMISSION CONTROL ECU ASSEMBLY BRANCH WIRE) 

OK: Go to next step 

1. Measure the resistance according to the value(s) in the table below.
   Fig 2: Identifying A24 Connector Terminal

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A24-1 (E1) - Body ground	Cable disconnected from negative (-) auxiliary battery terminal	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Transmission Control ECU Assembly)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (GROUND CIRCUIT) 

OK: Go to next step 

1. Connect the cable to the negative (-) auxiliary battery terminal.
2. Measure the voltage according to the value(s) in the table below.
   Fig 3: Identifying A23 Connector Terminal

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   A23-16 (+B) - Body ground	Power switch on (IG)	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Transmission Control ECU Assembly)

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

OK → See step   5