DESCRIPTION
The Transmission Control Module (TCM) and ECM perform 2-way communication with each other via the Controller Area Network (CAN). The TCM sends signals to the ECM concerning required engine speed, required engine torque, warning indicators in the combination meter, DTCs and other data. The ECM sends signals to the TCM concerning engine speed, opening angle of the throttle valve, temperature of intake air, temperature of engine coolant, engine torque and other data. If the TCM cannot communicate with the ECM, the TCM will conclude that there is a malfunction in the CAN system, illuminate the MIL and set a DTC.
DTC No. |
DTC Detection Condition |
Trouble Area |
---|---|---|
U0101 |
|
|
MONITOR STRATEGY
Related DTCs |
U0101: Lost Communication with TCM |
Required Sensors/Components (Main) |
ECM |
Required Sensors/Components (Related) |
- |
Frequency of Operation |
Continuous |
Duration |
1.25 seconds |
MIL Operation |
Immediate |
Sequence of Operation |
None |
TYPICAL ENABLING CONDITIONS
Monitor runs whenever following DTCs are not present |
None |
All of the following conditions are met |
- |
Battery voltage |
10.5 V or more (More than 1 second) |
Ignition switch |
ON |
Starter |
Off |
TYPICAL MALFUNCTION THRESHOLDS
Communication signal |
Lost communication with TCM |
CONFIRMATION DRIVING PATTERN
HINT:
Techstream Display |
Description |
---|---|
NORMAL |
|
ABNORMAL |
|
INCOMPLETE |
|
N/A |
|
HINT:
HINT:
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
HINT:
Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.
PROCEDURE
1. |
CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC U0101) |
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: System Select / Health Check.
(e) 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.
B | ![]() |
GO TO DTC CHART |
|
2. |
INSPECT ECU POWER SOURCE CIRCUIT (TCM POWER SOURCE) |
(a) Disconnect the TCM connector. |
|
(b) Turn the Ignition switch to ON.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection |
Condition |
Specified Condition |
---|---|---|
B40-1 (BATT) - B40-8 (E1) |
Always |
11 to 14 V |
B40-18 (+B) - B40-8 (E1) |
Ignition switch ON |
11 to 14 V |
*a |
Front view of wire harness connector (to TCM) |
Result |
Proceed to |
---|---|
OK |
A |
NG (for U760E) |
B |
NG (for U760F) |
C |
B | ![]() |
GO TO TCM POWER SOURCE CIRCUIT |
C | ![]() |
GO TO TCM POWER SOURCE CIRCUIT |
|
3. |
CHECK HARNESS AND CONNECTOR (ECM - TCM) |
(a) Disconnect the TCM connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Tester Connection |
Condition |
Specified Condition |
---|---|---|
B40-6 (CAN+) - B58-24 (CAN+) |
Always |
Below 1 Ω |
B40-7 (CAN-) - B58-1 (CAN-) |
Always |
Below 1 Ω |
Standard Resistance (Check for Short):
Tester Connection |
Condition |
Specified Condition |
---|---|---|
B40-6 (CAN+) or B58-24 (CAN+) - Body ground |
Always |
10 kΩ or higher |
B40-7 (CAN-) or B58-1 (CAN-) - Body ground |
Always |
10 kΩ or higher |
Result |
Proceed to |
---|---|
OK (for U760E) |
A |
OK (for U760F) |
B |
NG |
C |
B | ![]() |
GO TO STEP 5 |
C | ![]() |
REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - TCM) |
|
4. |
REPLACE TCM |
(a) Replace the TCM (for U760E) (See page
).
NEXT | ![]() |
GO TO STEP 6 |
5. |
REPLACE TCM |
(a) Replace the TCM (for U760F) (See page
).
|
6. |
CHECK WHETHER DTC OUTPUT RECURS (DTC U0101) |
(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 / Engine / Trouble Codes.
(e) Read the DTCs.
Result |
Proceed to |
---|---|
DTC is not output |
A |
DTC U0101 is output |
B |
A | ![]() |
END |
B | ![]() |
REPLACE ECM |
Short in Driver Side Knee Airbag Squib Circuit (B1860/64-B1863/64)
DESCRIPTION
The driver side knee airbag squib circuit consists of the center airbag sensor
assembly and driver side knee airbag assembly.
The center airbag sensor assembly uses this circuit to deploy the airbag when
deployment conditions are met.
These ...
Data List / Active Test
DATA LIST / ACTIVE TEST
1. DATA LIST
HINT:
Using the Techstream to read the Data List allows the values or states of switches,
sensors, actuators and other items to be read without removing any parts. This non-intrusive
inspection can be very useful bec ...
On-vehicle Inspection
ON-VEHICLE INSPECTION
CAUTION / NOTICE / HINT
HINT:
Use the same procedure for the RH side and LH side.
The procedure listed below is for the LH side.
PROCEDURE
1. REMOVE REAR WHEEL
2. SEPARATE REAR FLEXIBLE HOSE
3. SEPARATE REAR DI ...