Lexus ES: Lost Communication with ECM/PCM "A" Missing Message (U010087)
DESCRIPTION
The engine control unit and transmission control unit are located inside the ECM. The engine control unit intercommunicates with the transmission control unit using CAN communication.
If there is a problem in this intercommunication, the ECM stores this DTC.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | MIL | Memory | Note |
|---|---|---|---|---|---|---|
| U010087 | Lost Communication with ECM/PCM "A" Missing Message | While the engine switch is on (IG), there is no communication between the engine control unit and transmission control unit for 1.25 seconds or more (1-trip detection logic). | ECM | Comes on | DTC stored | SAE Code: U0100 |
MONITOR STRATEGY
| Related DTCs | U0100: Verify communication |
| Required sensors/components (Main) | ECM |
| Required sensors/components (Related) | - |
| Frequency of Operation | Continuous |
| Duration | 1.25 sec. |
| MIL Operation | Immediately |
| Sequence of Operation | None |
TYPICAL ENABLING CONDITIONS
| The monitor will run whenever the following DTCs are not stored | None |
| Battery Voltage | 10.5 V or more |
| Engine switch | On (IG) |
| Starter | Off |
TYPICAL MALFUNCTION THRESHOLDS
| Communication signal | Lost communication with ECM/PCM |
CONFIRMATION DRIVING PATTERN
HINT:
- After repairs have been completed, clear the DTCs and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.
-
When clearing the permanent DTCs, refer to the Clear Permanent DTC procedure.
Click here
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- Connect the Techstream to the DLC3.
- Turn the engine switch on (IG) and turn the Techstream on.
- Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
- Turn the engine switch off and wait for 2 minutes or more.
- Turn the engine switch on (IG) and turn the Techstream on.
-
Wait for 3 seconds or more with the engine switch on (IG). [*1]
HINT:
[*1] : Normal judgment procedure.
The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
- Enter the following menus: Powertrain / Transmission / Utility / All Readiness.
- Input the DTC: U010087.
-
Check the DTC judgment result.
Techstream Display
Description
NORMAL
- DTC judgment completed
- System normal
ABNORMAL
- DTC judgment completed
- System abnormal
INCOMPLETE
- DTC judgment not completed
- Perform driving pattern after confirming DTC enabling conditions
N/A
- Unable to perform DTC judgment
- Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit
HINT:
- If the judgment result shows NORMAL, the system is normal.
- If the judgment result shows ABNORMAL, the system has a malfunction.
- If the judgment result shows INCOMPLETE or N/A, perform the normal judgment procedure again.
CAUTION / NOTICE / HINT
NOTICE:
-
Perform the universal trip to clear permanent DTCs.
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-
Perform registration and/or initialization when parts related to the automatic transaxle are replaced.
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PROCEDURE
| 1. | CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC U010087) |
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Transmission / Trouble Codes.
Powertrain > Transmission > Trouble Codes(e) Read the DTCs using the Techstream.
| Result | Proceed to |
|---|---|
| Only DTC U010087 is output | A |
| DTC U010087 and other DTCs are output | B |
| B | .gif) | GO TO DTC CHART |
|
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| 2. | REPLACE ECM |
(a) Replace the ECM.
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| NEXT | | PERFORM REGISTRATION |
READ NEXT:
Components
COMPONENTS ILLUSTRATION *1 DRIVE MODE SELECT SWITCH (COMBINATION SWITCH ASSEMBLY) *2 INSTRUMENT CLUSTER FINISH PANEL ASSEMBLY
Inspection
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