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DTC U1E05-87: Lost Communication with ASC
 
 
caution
  • If DTC U1E05-87 is set in the ECM, surely perform CAN bus line diagnostic.
  • Replace ECU after certainly confirming that the communication circuits are normal.
 
 
DESCRIPTIONS OF MONITOR METHODS
There is no data from ABS actuator and electric unit (control unit) for the specified time [ABS actuator and electric unit (control unit) also detect communication error with ECM].
 
 
MONITOR EXECUTION
Continuous.
 
 
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC set in memory for the item monitored below)
  • Not applicable
Sensor (The sensor below is determined to be normal)
  • Not applicable
 
 
DTC SET CONDITIONS
Logic Flow Chart
Check Conditions
  • Power supply mode of electric motor switch is ON.
  • 12V battery positive voltage is more than 10.0 volts and is less than 16.5 volts.
Judgment Criterion
  • Unable to receive ABS actuator and electric unit (control unit) signals through the CAN bus line for 4 seconds.
 
 
COMMENT
Current Trouble
  • Some of the possible causes are a harness or connector damage between the ECM and the ABS actuator and electric unit (control unit) on the CAN bus line, a failure in the ABS actuator and electric unit (control unit) power supply system, a failure in the ABS actuator and electric unit (control unit), or a failure in the ECM.
Past Trouble
  • Proceed to troubleshoot based on a harness or connector damage on the CAN bus line between the ECM and ABS actuator and electric unit (control unit), and a failure in the ABS actuator and electric unit (control unit) power supply system. For diagnostic procedure, refer to how to cope with past malfunctions (Refer to GENERAL INFORMATION, General Information – How to Use Troubleshooting/Inspection Service Points – How to Treat Past Trouble HOW TO TREAT PAST TROUBLE).
noteIf a malfunction occurred in the past, a failure cannot be discovered through the scan tool (M.U.T.-III SE) CAN bus diagnosis even if there might be a problem with the CAN bus. In this case, refer to GENERAL INFORMATION, General Information – How to Use Troubleshooting/Inspection Service Points – How to Cope with Intermittent Malfunctions HOW TO COPE WITH INTERMITTENT MALFUNCTIONS). Furthermore, it is possible to narrow down the areas of the possible failures from the DTCs that are set in the ECUs, which are communicating on the CAN bus (Refer to ELECTRICAL & POWER CONTROL, LAN System – CAN Fundamental – Basic Inspection – Diagnosis and Repair Workflow – Trouble Diagnosis Flow Chart Trouble Diagnosis Flow Chart).
 
 
FAIL-SAFE AND BACKUP FUNCTION
None.
 
 
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 1 OBD- II DRIVE CYCLE.
 
 
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
  • CAN line harness damage or connector damage.
  • ABS actuator and electric unit (control unit) failed.
  • ECM failed.
 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite main harness A
  • MB992747: V.C.I.-Lite USB cable short
  • MB992748: V.C.I.-Lite USB cable long
1.STEP 1. Using scan tool (M.U.T.-IIISE), diagnostic CAN bus line.
Use scan tool (M.U.T.-III SE) to perform CAN bus line diagnostic (Refer to ELECTRICAL & POWER CONTROL, LAN System – CAN Fundamental – Basic Inspection – Diagnosis and Repair Workflow – Trouble Diagnosis Flow Chart Trouble Diagnosis Flow Chart).
Q: Is the CAN bus line normal?
Repair CAN bus line (Refer to ELECTRICAL & POWER CONTROL, LAN System – CAN – DTC/Circuit Diagnosis – Malfunction Area Chart – Drivetrain CAN Communication Circuit Drivetrain CAN Communication Circuit). Then
 
2.STEP 2. Using scan tool (M.U.T.-III SE), read the other system DTC.
Use scan tool (M.U.T.-III SE) to check and see if a DTC is set in the ABS actuator and electric unit (control unit).
Q: Is any DTC set in the ABS actuator and electric unit (control unit)?
Perform troubleshooting of ABS actuator and electric unit (control unit) (Refer to BRAKES, Brake Control System – With ABS Actuator and Electric unit (Control Unit) – ECU Diagnosis Information – ABS Actuator and Electric Unit (Control Unit) – DTC Index DTC Index).
 
3.STEP 3. Using scan tool (M.U.T.-III SE), read the other system DTC.
Use scan tool (M.U.T.-III SE) to check and see if a DTC of ASC CAN timeout is set in the PHEV-ECU(Refer to ELECTRIC POWER TRAIN, PHEV-ECU – Troubleshooting – Diagnosis Function DIAGNOSTIC FUNCTION), and check whether the DTC of CAN communication error (ABS control unit) is set in the chassis control module.
Q: Is the DTC of ASC CAN timeout set in the PHEV-ECU? Or Is the DTC of CAN communication error (ABS control unit) set in the chassis control module?
 
4.STEP 4. Test the OBD-II drive cycle.
After erasing the DTC, carry out test drive with the drive cycle pattern, and recheck the DTC.
(1) Use scan tool (M.U.T.-III SE) to erase the DTC.
(2) Carry out test drive with the drive cycle pattern (Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 1 OBD- II DRIVE CYCLE).
(3) Use scan tool (M.U.T.-III SE) to recheck the DTC.
Q: Is DTC U1E05-87 set?
Replace the ABS actuator and electric unit (control unit) (Refer to BRAKES, Brake Control System – With ABS Actuator and Electric unit (Control Unit) – Removal and Installation – ABS Actuator and Electric unit (Control Unit) Removal and Installation). Then
Intermittent malfunction in CAN bus line between ECM and ABS actuator and electric unit (control unit) (Refer to GENERAL INFORMATION, General Information – How to Use Troubleshooting/Inspection Service Points – How to Cope with Intermittent Malfunctions HOW TO COPE WITH INTERMITTENT MALFUNCTIONS).
 
5.STEP 5. Test the OBD-II drive cycle.
After erasing the DTC, carry out test drive with the drive cycle pattern, and recheck the DTC.
(1) Use scan tool (M.U.T.-III SE) to erase the DTC.
(2) Carry out test drive with the drive cycle pattern (Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 1 OBD- II DRIVE CYCLE).
(3) Use scan tool (M.U.T.-III SE) to recheck the DTC.
Q: Is DTC U1E05-87 set?
Replace the ECM (Refer to ENGINE CONTROL MODULE (ECM) REMOVAL AND INSTALLATION). Then
Intermittent malfunction in CAN bus line between ECM and ABS actuator and electric unit (Refer to GENERAL INFORMATION – General Information, How to Use Troubleshooting/Inspection Service Points, How to Cope with Intermittent Malfunctions HOW TO COPE WITH INTERMITTENT MALFUNCTIONS).
 
6.STEP 6. Test the OBD-II drive cycle.
After erasing the DTC, carry out test drive with the drive cycle pattern, and recheck the DTC.
(1) Use scan tool (M.U.T.-III SE) to erase the DTC.
(2) Carry out test drive with the drive cycle pattern (Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 1 OBD- II DRIVE CYCLE).
(3) Use scan tool (M.U.T.-III SE) to recheck the DTC.
Q: Is DTC U1E05-87 set?
Retry the troubleshooting
The inspection is complete.