Ae80F Automatic Transmission Transaxle. Dtc U0100 Lost Communication With Ecm / Pcm A

Drivetrain. Land Cruiser. Urj200, 202 Grj200 Vdj200

Ae80F Automatic Transmission Transaxle. Land Cruiser. Urj200, 202 Grj200 Vdj200

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT ECM

CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)

CHECK HARNESS AND CONNECTOR (ECM - TCM)

REPLACE TCM

CHECK DTC OUTPUT

DTC U0100 Lost Communication with ECM / PCM "A"

DESCRIPTION

The ECM communicates with the TCM via the Controller Area Network (CAN).
If there is a problem in communication, the TCM stores this DTC.

DTC No.	DTC Detection Condition Diagnosis Condition Malfunction Status Malfunction Time Other	Trouble Area
U0100	Battery voltage is 9.5 V or higher. No communication between the ECM and TCM 1.25 seconds 1-trip detection logic	Harness or connector ECM TCM

WIRING DIAGRAM

Land Cruiser. Urj200, 202 Grj200 Vdj200.Ae80F Automatic Transmission Transaxle.Automatic Transmission System.
Dtc
U0100 Lost Communication With Ecm / Pcm A

INSPECTION PROCEDURE

NOTICE:

Perform registration and/or initialization when parts related to the automatic transmission are replaced (Click here).

HINT:

If the CAN communication system malfunctions, the TCM cannot receive current data from the ECM. In this case, the freeze frame data output from the TCM is not updated, so the data will not be useful for the inspection. However, reading the Data List as the first step in troubleshooting is an effective way to find malfunctions.
The malfunctioning area can be checked using the CAN Bus Check function on the GTS.
After performing repair, clear the DTCs and perform the following procedure to check that DTCs are not output.

Check the battery voltage is 9.5 V or higher.
Turn the engine switch on (IG).
Check for DTCs again (Click here).

1.INSPECT ECM

Disconnect the ECM connector.

Turn the engine switch on (IG).

Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection
Switch Condition
Specified Condition
A38-2 (+B) - Body ground
Engine switch on (IG)
11 to 14 V
A38-3 (+B2) - Body ground
Engine switch on (IG)
11 to 14 V
Text in Illustration
*a
Front view of wire harness connector
(to ECM)

Text in Illustration
*a	Front view of wire harness connector (to ECM)

GO TO ECM POWER SOURCE CIRCUIT (ENGINE CONTROL SYSTEM / SFI SYSTEM) (Click here)

OK

2.CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)

Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection
Condition
Specified Condition
C45-81 (E1) - Body ground
Always
Below 1 Ω
Text in Illustration
*a
Front view of wire harness connector
(to ECM)

Text in Illustration
*a	Front view of wire harness connector (to ECM)

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.CHECK HARNESS AND CONNECTOR (ECM - TCM)

Disconnect the A38 ECM connector.

Disconnect the A82 TCM connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A38-10 (CANP) - A82-1 (CAN+)	Always	Below 1 Ω
A38-18 (CANN) - A82-2 (CAN-)	Always	Below 1 Ω
A38-10 (CANP) or A82-1 (CAN+) - Body ground	Always	10 kΩ or higher
A38-18 (CANN) or A82-2 (CAN-) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.REPLACE TCM

Replace the TCM (Click here).

NEXT

5.CHECK DTC OUTPUT

Clear the DTCs (Click here).

Start the engine.

Read the DTCs (Click here).

Result
Result
Proceed to
DTCs are not output
A
DTC U0100 is output
B

Result
Result	Proceed to
DTCs are not output	A
DTC U0100 is output	B

REPLACE ECM (Click here)

END

Tester Connection	Switch Condition	Specified Condition
A38-2 (+B) - Body ground	Engine switch on (IG)	11 to 14 V
A38-3 (+B2) - Body ground	Engine switch on (IG)	11 to 14 V