Toyota Venza: Lost Communication with ECM / PCM "A" (U0100)
DESCRIPTION
The engine control unit communicates with the TCM using the Controller Area Network (CAN).
If there is a problem in this communication, the TCM sets a DTC.
|
DTC No. |
DTC Detection Condition |
Trouble Area |
|---|---|---|
|
U0100 |
Following conditions are met for 1.25 seconds (1 trip detection logic):
|
|
MONITOR STRATEGY
|
Related DTCs |
U0100: Verify communication |
|
Required Sensors/Components (Main) |
TCM |
|
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 not present |
None |
|
Battery Voltage |
10.5 V or more |
|
Ignition Switch |
ON |
|
Starter |
OFF |
TYPICAL MALFUNCTION THRESHOLDS
|
Communication between TCM and ECM |
No communication |
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
Perform the universal trip to clear permanent DTCs (See page
.gif)
).
HINT:
- Refer to inspection procedure for CAN communication system.
- If the CAN communication malfunctions, the TCM cannot receive the 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 effective to find malfunctions.
- The malfunction area can be checked using the Bus Check function on
the Techstream (See page ).
PROCEDURE
|
1. |
CHECK ECU TERMINAL VOLTAGE (+B AND E1 TERMINALS) |
|
(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 |
Switch Condition |
Specified Condition |
|---|---|---|
|
B40-18 (+B) - B40-8 (E1) |
Ignition switch ON |
9 to 14 V |
(d) Turn the ignition switch off.
(e) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
B40-8 (E1) - Body ground |
Always |
Below 1 Ω |
|
*1 |
Front view of wire harness connector (to TCM) |
| NG | .gif) |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
.gif)
|
2. |
CHECK HARNESS AND CONNECTOR (TCM - ECM) |
|
(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:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
B40-6 (CAN+) - B39-24 (CAN+) |
Always |
Below 1 Ω |
|
B40-7 (CAN-) - B39-1 (CAN-) |
Always |
Below 1 Ω |
|
B40-6 (CAN+) or B39-24 (CAN+) - Body ground or other terminals |
Always |
1 MΩ or higher |
|
B40-7 (CAN-) or B39-1 (CAN-) - Body ground or other terminals |
Always |
1 MΩ or higher |
|
*1 |
Front view of wire harness connector (to ECM) |
|
*2 |
Front view of wire harness connector (to TCM) |
| NG | |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
3. |
CHECK IF DTC OUTPUT RECURS |
(a) Connect the Techstream to the DLC3.
(b) Clear the DTCs.
(c) Replace the TCM.
HINT:
Replace the TCM with a TCM from a normally functioning vehicle of the same model.
(d) Start the engine.
(e) Read the DTCs.
|
Display (DTC Output) |
Proceed to |
|---|---|
|
U0100 |
A |
|
No DTC |
B |
| A | |
REPLACE ECM |
| B | |
REPLACE TCM |
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...
0.2245