U760E Automatic Transaxle

U760E AUTOMATIC TRANSMISSION / TRANSAXLE: AUTOMATIC TRANSAXLE SYSTEM: U0100: Lost Communication with ECM / PCM "A"
U0100 - Lost Communication with ECM / PCM "A"

DESCRIPTION

The ECM communicates with the TCM using the Controller Area Network (CAN).

If there is a problem with this communication, the TCM stores a DTC.





MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
Perform the universal trip to clear permanent DTCs Reading and Clearing Diagnostic Trouble Codes.

HINT
* Refer to the inspection procedure for the CAN communication system.
* If the CAN communication malfunctions, the TCM cannot receive current data from the ECM. In this case, the freeze frame data output from the TCM has not been 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 confirmed using the Bus Check function of the Techstream Diagnosis System.

PROCEDURE

1. CHECK TCM (POWER SOURCE, BODY GROUND)

(a) Disconnect the TCM connector.





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

Standard Voltage:





(c) Turn the ignition switch off.

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

Standard Resistance:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (TCM - BATTERY, BODY GROUND)
OK -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (ECM - TCM)

(a) Disconnect the ECM connector.

(b) Disconnect the TCM connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

3. CHECK IF DTC OUTPUT RECURS (DTC U0100)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / ECT / Trouble Codes / Clear.

(e) Replace the TCM Removal.

HINT
Replace the TCM with the TCM of a normally functioning vehicle of the same model.

(f) Start the engine.

(g) Enter the following menus: Powertrain / ECT / Trouble Codes.

(h) Read the DTCs using the Techstream.

Result





B -- REPLACE TCM Removal

A -- REPLACE ECM Removal