DTC U0101: Lost Communication with TCM [12/2013 - 11/2016]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: System Select / Health Check.
5. Read the DTCs.

   Result	Proceed to
   DTC U0101 is output	A
   DTC U0101 and other DTCs are output	B

   HINT: 

   If any DTCs other than U0101 are output, troubleshoot those DTCs first.

Result: 

B 

GO TO DTC CHART 

Result: 

A 

See step  2

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the TCM connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   C3-1 (BATT) - C3-8 (E1)	Always	11 to 14 V

3. Turn the ignition switch to ON.
4. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   C3-18 (+B) - C3-8 (E1)	Ignition switch ON	11 to 14 V

   Proceed to
   OK
   NG

Result: 

NG 

GO TO TCM POWER SOURCE CIRCUIT 

for U660E: Refer to ECU Power Source Circuit [12/2013 - 11/2016]

for U660F: Refer to ECU Power Source Circuit [12/2013 - 11/2016]

Result: 

OK 

See step  3

1. Disconnect the TCM connector.
2. Disconnect the ECM connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   C3-6 (CAN+) - C1-31 (CAN+)	Always	Below 1 Ω
   C3-7 (CAN-) - C1-1 (CAN-)	Always	Below 1 Ω
   C3-6 (CAN+) or C1-31 (CAN+) - Body ground	Always	10 kΩ or higher
   C3-7 (CAN-) or C1-1 (CAN-) - Body ground	Always	10 kΩ or higher

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

1. Replace the TCM.

   for U660E: Refer to REMOVAL [12/2013 - 11/2016]

   for U660F: Refer to REMOVAL [12/2013 - 11/2016]

Result: 

NEXT 

See step  5

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [12/2013 - 11/2016]

   Powertrain > Engine > Clear DTCs 

5. Turn the ignition switch off and wait for at least 30 seconds.
6. Turn the ignition switch to ON and turn the Techstream on.
7. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
8. Enter the following menus: Powertrain / Engine / Trouble Codes.
9. Read the DTCs.

   Powertrain > Engine > Trouble Codes 

   Result	Proceed to
   DTCs are not output	A
   DTC U0101 is output	B

Result: 

A 

END 

Result: 

B 

REPLACE ECM. 

Refer to  REMOVAL [12/2013 - 11/2016]