DTC B1E27: Multichannel Driver CH3 Defective (Open/Short): Diagnosis

Required Special Tools: 

• MB992006: Extra fine probe
• MB991223: Harness set

1. 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. 

   Q: Is DRL relay connector A-27X, ETACS-ECU connector C-410 in good condition? 

   YES  : Go to Step  2.

   NO  : Repair or replace the damaged component(s). (Refer to HARNESS CONNECTOR INSPECTION .)

2. 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.

   Q: 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? 

   YES  : Go to Step  3.

   NO  : 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.

3. 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.

   Q: Is the DTC set? 

   YES  : Replace the ETACS-ECU.

   NO  : The trouble can be an intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS ).