Inspection Procedure O-4
The ETACS-ECU does not receive any signal from all the door switches.All Door Switches Input Circuit Part 1:
All Door Switches Input Circuit Part 2:
CIRCUIT OPERATION
The ETACS-ECU operates the following functions or systems according to signal from all door switches:
- Light reminder tone alarm function
- Power window timer function
- Sunroof timer function
- Headlight automatic shutdown function
- Keyless entry system
- Dome light
- Door-ajar indicator light
- Ignition key cylinder illumination light
TECHNICAL DESCRIPTION (COMMENT)
If the signal is not normal, the functions or systems, which are described in "CIRCUIT OPERATION", do not work normally. If the signal is not normal, the door switches or the ETACS-ECU may be defective.
TROUBLESHOOTING HINTS
- The all door switches may be defective.
- 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:
- MB991223: Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991496: Main unit
- MB991497: Test Harness (for communication)
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B
STEP 1. Check the input signal (by using the pulse check mode of the monitor).
Check the input signals from the all door switches.
CAUTION: To prevent damage to scan tool MB991502 or MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502 or MB991958.
1. Connect the special tool. Refer to "How to connect SWS monitor."
2. Operate scan tool MB991502 or MB991958 according to the procedure below to display "Pulse check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "Pulse Checking."
3. When the front and rear doors are opened, check if scan tool MB991502 or MB991958 sounds or not.
Q: When the front and rear doors are opened, does scan tool MB991502 or MB991958 sound?
When the front doors are opened, scan tool MB991502 or MB991958 does not sound.: Refer to Inspection Procedure N-5 "ETACS-ECU does not receive any signal from the driver's or the front passenger's door switch".
When the rear door (LH) is opened, scan tool MB991502 or MB991958 does not sound.: Go to Step 2.
When the rear door (RH) is opened, scan tool MB991502 or MB991958 does not sound.: Go to Step 7.
STEP 2. Check door switch (rear: LH) connector D-11 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is door switch (rear: LH) connector D-11 in good condition?
YES: Go to Step 3.
NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door switch (rear: LH) should be normal.
STEP 3. Check the door switch (rear: LH).
Remove the door switch (rear: LH). Then check continuity between the switch terminals and switch body.
Q: Is the door switch (rear: LH) in good condition?
YES: Go to Step 4.
NO: Replace the door switch (rear: LH). If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door switch (rear: LH) should be normal.
STEP 4. 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?
YES: Go to Step 5.
NO: Check the fit of the switch, and repair if necessary. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the rear door switch (LH) should be normal.
STEP 5. Check and ETACS-ECU connector C-226 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is ETACS-ECU connector C-226 in good condition?
YES: Go to Step 6.
NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door switch (rear: LH) should be normal.
STEP 6. Check the wiring harness between door switch (rear: LH) connector D-11 (terminal 2) and ETACS-ECU connector C-226 (terminal 7).
NOTE: Also check junction block connector C-217 for loose. corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connector C-217 is damaged, Repair or replace the damaged component(s) as described in Harness Connector Inspection.
Q: Is the wiring harness between door switch (rear: LH) connector D-11 (terminal 2) and ETACS-ECU connector C-226 (terminal 7) in good condition?
YES: Replace the ETACS-ECU. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door switch (rear: LH) should be 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. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door switch (rear: LH) should be normal.
STEP 7. Check door switch (rear: RH) connector D-08 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is rear door switch (rear: RH) connector D-08 in good condition?
YES: Go to Step 8.
NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door switch (rear: RH) should be normal.
STEP 8. Check the door switch (rear: RH).
Remove the door switch (rear: RH). Then check continuity between the switch terminals.
Q: Is the door switch (rear: RH) in good condition?
YES: Go to Step 9.
NO: Replace the door switch (rear: RH). If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door switch (rear: RH) should be normal.
STEP 9. Measure at the lower metal part of the door switch (rear: RH) in order to check the ground circuit to the door switch (rear: RH).
NOTE: Check that the door switch (rear: RH) 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 10.
NO: Check the fit of the switch, and repair if necessary. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door switch (rear: RH) should be normal.
STEP 10. Check ETACS-ECU connector C-226 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is ETACS-ECU connector C-226 in good condition?
YES: Go to Step 11.
NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door switch (rear: RH) should be normal.
STEP 11. Check the wiring harness between door switch (rear: RH) connector D-08 (terminal 2) and ETACS-ECU connector C-226 (terminal 7).
NOTE: Also check intermediate connector C-113 and junction block connector C-214 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-113 or junction block connector C-214 is damaged, Repair or replace the damaged components) as described in Harness Connector Inspection.
Q: Is the wiring harness between door switch (rear: RH) connector D-08 (terminal 2) and ETACS-ECU connector C-226 (terminal 7) in good condition?
YES: Replace the ETACS-ECU. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door switch (rear: RH) should be 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. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the door switch (rear: RH) should be normal.