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DTC B1E27 Multichannel Driver CH3 Defective (Open/Short)
 
 
cautionBefore replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
 
 
TROUBLE JUDGMENT
If the daytime running light fails, the ETACS-ECU will set DTC No. B1E27.
 
 
TECHNICAL DESCRIPTION (COMMENT)
DTC No. B1E27 will be set if the ETACS-ECU detects a short to power supply between the daytime running light relay and the ETACS-ECU.
 
 
TROUBLESHOOTING HINTS
  • The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
  • The ETACS-ECU may be defective
 
 
DIAGNOSIS
Required Special Tools:
  • MB992006: Extra fine probe
  • MB991223: Harness set
STEP 1. Check DRL relay connector A-27X, ETACS-ECU connector C-410 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Is DRL relay connector A-27X, ETACS-ECU connector C-410 in good condition?
Go to Step 2
Repair or replace the damaged component(s). Refer to GROUP 00E, Harness Connector Inspection .
 
STEP 2. Check the wiring harness between DRL relay connector A-27X (terminal 2) and ETACS-ECU connector C-410 (terminal 10).
Check the input line for short circuit.
Is the wiring harness between DRL relay connector A-27X (terminal 2) and ETACS-ECU connector C-410 (terminal 10) and the ground in good condition?
Go to Step 3
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
 
STEP 3. Using scan tool MB991958, check whether the DTC is set again.
Check again if DTC No.B1E27 is set in the ETACS-ECU.
(1) Erase the DTC.
(2) Turn the ignition switch from the LOCK (OFF) position to the ON position to start the engine.
(3) Release the parking brake lever.
(4) Check if DTC is set.
Is the DTC set?
Replace the ETACS-ECU.
The trouble can be an intermittent malfunction (GROUP 00 - How to use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).