Inspection Procedure 5

Inspection Procedure 5: ETACS-ECU does not receive any signal from the front door switch (LH).














TECHNICAL DESCRIPTION (COMMENT)

If there is an error to the front door switch (LH) input signal, the front door switch
(LH) signal is no longer output to the communication line.

TROUBLESHOOTING HINTS

- The front door switch (LH) may be defective
- The ETACS-ECU may be defective
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector

DIAGNOSIS

Required Special Tools:

- MB991223: Harness Set
- MB992006: Extra Fine Probe

STEP 1. Check front door switch (LH) connector D-28 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is front door switch (LH) connector D-28 in good condition?

YES Go to Step 2.
NO Repair or replace the damaged component(s) Harness Connector Inspection). Check that the input signal of front door switch
(LH) is normal.
STEP 2. Check the front door switch (LH).

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





Q. Is the driver's door switch in good condition?

YES Go to Step 3.
NO Replace the front door switch (LH). Check that the input signal of front door switch (LH) is normal.
STEP 3. Measure at the lower metal part of the front door switch (LH) in order to check the ground circuit to the front door switch (LH).

NOTE:
Check that the front 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?

YES Go to Step 4.
NO Check the fit of the switch, and repair if necessary. Check that the input signal of front door switch (LH) is normal.
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?

YES Go to Step 5.
NO Repair or replace the damaged component(s) Harness Connector Inspection). Check that the input signal of front door switch
(LH) is normal.
STEP 5. Check the wiring harness between driver's door switch connector D-28 (terminal 3) and ETACS-ECU connector C-313 (terminal 16).

Check the input lines for open circuit and short circuit.

Q. Is the wiring harness between driver's door switch connector D-28 (terminal 3) and ETACS-ECU connector C-313 (terminal 16) in good condition?

YES Replace the ETACS-ECU. Check that the input signal of front door switch (LH) is normal.
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 front door switch (LH) is normal.