Inspection Procedure 7: ETACS-ECU Does Not Receive Any Signal From The Rear Door Switch (LH): Diagnosis

Required Special Tools: 

• MB991223: Harness Set
• MB992006: Extra Fine Probe

1. STEP 1. Check rear door switch (LH) connector D-19 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is rear door switch (LH) connector D-19 in good condition? 

   1. YES:  Go to Step 2.
   2. NO:  Repair or replace the damaged component(s) (Refer to HARNESS CONNECTOR INSPECTION ). Check that the input signal of rear door switch (LH) is normal.
2. STEP 2. Check the rear door switch (LH). 

   Remove the rear door switch (LH). Then check the continuity between the switch terminals and the switch body.

   CONTINUITY SPECIFICATION
   
   

   Switch position	Tester connection	Specified condition
   Released	3 -switch body	Continuity exists (2 ohms or less)
   Pressed	3 -switch body	Open circuit

   Q: Is the rear door switch in good condition? 

   1. YES:  Go to Step 3.
   2. NO:  Replace the rear door switch (LH). Check that the input signal of rear door switch (LH) is normal.
3. STEP 3. Measure at the lower metal part of the rear door switch (LH) in order to check the ground circuit to the rear door switch (LH). 
   NOTE: Check that the rear door switch (LH) is grounded to the vehicle body by means of its mounting screw.

   Remove the cap, and measure the resistance value between the lower metal part and the ground.

   • The resistance should equal 2 ohms or less.

     Q: Is the measured resistance 2 ohms or less? 

     1. YES:  Go to Step 4.
     2. NO:  Check the fit of the switch, and repair if necessary. Check that the input signal of rear door switch (LH) is normal.
4. STEP 4. Check ETACS-ECU connector C-313 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is ETACS-ECU connector C-313 in good condition? 

   1. YES:  Go to Step 5.
   2. NO:  Repair or replace the damaged component(s) (Refer to HARNESS CONNECTOR INSPECTION ). Check that the input signal of rear door switch (LH) is normal.
5. STEP 5. Check the wiring harness between driver's door switch connector D-19 (terminal 3) and ETACS-ECU connector C-313 (terminal 7). 

   Check the input lines for open circuit and short circuit.

   Q: Is the wiring harness between rear door switch connector D-19 (terminal 3) and ETACS-ECU connector C-313 (terminal 7) in good condition? 

   1. YES:  Replace the ETACS-ECU. Check that the input signal of rear door switch (LH) is normal.
   2. 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. Check that the input signal of rear door switch (LH) is normal.