DTC Code | DTC Name |
---|---|
U0100 | Lost Communication with ECM / PCM "A" |
DESCRIPTION
The 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 rpm, required engine torques, warning indicators in the combination meter, DTCs and other data. The ECM sends signals to the TCM concerning engine rpm, opening angles of the throttle valve, temperature of intake air, temperature of engine coolant, engine torques 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 multi-mode manual transaxle warning light, and store this DTC.
DTC No. | Detection Item | DTC Detection Condition | Trouble Area | MIL | Warning Indicate | Memory |
---|---|---|---|---|---|---|
U0100 | Lost Communication with ECM / PCM "A" |
No communication with the ECM (1-trip detection logic) |
|
Comes on | Comes on | DTC stored |
WIRING DIAGRAM
*a | ECU-B NO. 2 |
*b | FL MAIN |
*c | Battery |
CAUTION / NOTICE / HINT
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 it will not be useful information for the inspection procedure. However, reading the Data List as the first step of troubleshooting is effective to find malfunctions.
Inspect the fuses for circuits related to this system before performing the following procedure.
In the table below, the values listed under Normal Condition are for reference only. Do not depend solely on these reference values when deciding whether a part is faulty or not.
DATA LIST
Warm up the engine.
Turn the ignition switch off.
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Multi-Mode M/T / Data List.
Powertrain > Multi-Mode M/T > Data ListTester Display | Measurement Item | Range | Normal Condition | Diagnostic Note |
---|---|---|---|---|
Calculated Engine Load | Load calculated by ECM | Min.: 0%, Max.: 100% | 10 to 25%: Idling 5 to 20%: Running without load (2500 rpm) | - |
Engine Coolant Temperature | Coolant temperature | Min.: -40°C, Max.: 140°C | 75 to 95°C (167 to 203°F): After engine warmed up |
|
Backup Engine Speed | Back-up engine speed | Min.: 0 rpm, Max.: 8160 rpm | 0 rpm: Engine stopped 720 to 820 rpm: Idling | 0 rpm displayed when malfunctions in CAN communication |
Accelerator Pedal Angle | Accelerator pedal angle | Min.: 0%, Max.: 100% | 0%: Accelerator pedal released | 0 % displayed when malfunctions in CAN communication regardless of the accelerator pedal status. |
Tester Display |
---|
Calculated Engine Load |
Engine Coolant Temperature |
Backup Engine Speed |
Accelerator Pedal Angle |
PROCEDURE
CHECK TCM (+B AND GND TERMINALS)
Disconnect the TCM connector.
*a |
Front view of wire harness connector (to TCM) |
Measure the voltage according to the value(s) in the table below.
Standard Voltage | ||||||
---|---|---|---|---|---|---|
|
Result | |||
---|---|---|---|
|
NG | Нажмите здесь |
OK |
CHECK HARNESS AND CONNECTOR (TCM - ECM)
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Result | |||
---|---|---|---|
|
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
REPLACE ECM
Replace the ECM.
for LHD: Click here Нажмите здесь
for RHD: Click here Нажмите здесь
ОСТОРОЖНО
Replace the ECM with a known good ECM of the same model vehicle.
Result | ||
---|---|---|
|
NEXT |
CHECK IF DTC RECURS
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Clear the DTCs.
Powertrain > Engine and ECT > Clear DTCsEnter the following menus: Powertrain / Engine and ECT / Trouble Codes.
Powertrain > Engine and ECT > Trouble CodesRead the DTCs.
Result | ||||||
---|---|---|---|---|---|---|
|
B |
END |
A |
REPLACE TCM
Replace the TCM.
Click here Нажмите здесь
Click here Нажмите здесь
Result | ||
---|---|---|
|
NEXT |
PERFORM INITIALIZATION
Perform the initialization and learning procedure.
Click hereНажмите здесь
Result | ||
---|---|---|
|
NEXT |
END |
CHECK HARNESS AND CONNECTOR (TCM - BODY GROUND)
Measure the resistance according to the value(s) in the table below.
*a |
Front view of wire harness connector (to TCM) |
Standard Resistance | ||||||
---|---|---|---|---|---|---|
|
Result | |||
---|---|---|---|
|
OK |
REPAIR OR REPLACE HARNESS OR CONNECTOR (TCM - BATTERY) |
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |