Inspection Procedure M-4
The ETACS-ECU does not Receive Any Signal from All the Door SwitchesAll Door Switches Input Circuit:
Connectors:
CIRCUIT OPERATION
The ETACS-ECU operates the following functions or systems according to signal from the driver's or front passenger's, rear or back door switches:
- Light reminder tone alarm function
- Power window timer function
- Headlight automatic shutdown function
- Keyless entry system
- Dome 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 driver's, front passenger's, rear or back door switch or the ETACS-ECU may be defective.
TROUBLESHOOTING HINTS
- Malfunction of the driver's, front passenger's, rear or back door switch
- Malfunction of the ETACS-ECU
- Damaged harness wires or connectors
DIAGNOSIS
Required Special Tools:
- MB991223: Test Harness Set
- MB991502: Scan Tool (MUT-II)
STEP 1. Check which door switch is defective.
Q: Which door switch signal is not entered?
Driver's or front passenger's door : Refer to Inspection Procedure L-4 "ETACS-ECU does not receive a signal from the driver's or the front passenger's door switch."
Rear door (LH): Go to Step 2.
Rear door (RH): Go to Step 6.
STEP 2. Check the rear door switch (LH).
Remove the rear door switch (LH). Then check continuity between the switch terminals.
Q: Is the rear door switch (LH) in good condition?
YES: Go to Step 3.
NO: Replace the rear door switch (LH). If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the rear door switch (LH) should be normal.
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 measured value should be 2 Ohm or less.
Q: Does the measured resistance value correspond with this range?
YES: Go to Step 4.
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 4. Check rear door switch (LH) connector D-11 and ETACS-ECU connector C-226 for damage.
Q: Are rear door switch (LH) connector D-11 and ETACS-ECU connector C-226 in good condition?
YES: Go to Step 5.
NO: Repair or replace the connector. Refer to Harness Connector Inspection. 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 the wiring harness between rear door switch (LH) connector D-11 and ETACS-ECU connector C-226.
NOTE: Also check junction block connector C-217. If junction block connector C-217 is damaged, repair or replace the connector as described in Harness Connector Inspection.
Q: Is the wiring harness between rear door switch (LH) connector D-11 and ETACS-ECU connector C-226 in good condition?
YES: Replace the ETACS-ECU. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the rear door switch (LH) should be normal.
NO: Repair the wiring harness. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the rear door switch (LH) should be normal.
STEP 6. Check the rear door switch (RH).
Remove the rear door switch (RH). Then check continuity between the switch terminals.
Q: Is the rear door switch (RH) in good condition?
YES: Go to Step 7.
NO: Replace the rear door switch (RH). If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the rear door switch (RH) should be normal.
STEP 7. Measure at the lower metal part of the rear door switch (RH) in order to check the ground circuit to the rear door switch (RH).
NOTE: Check that the rear door switch (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 measured value should be 2 Ohm or less.
Q: Does the measured resistance value correspond with this range?
YES: Go to Step 8.
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 (RH) should be normal.
STEP 8. Check rear door switch (RH) connector D-08 and ETACS-ECU connector C-226 for damage.
Q: Are rear door switch (RH) connector D-08 and ETACS-ECU connector C-226 in good condition?
YES: Go to Step 9
NO: Repair or replace the connector. Refer to Harness Connector Inspection. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the rear door switch (RH) should be normal.
STEP 9. Check the wiring harness between rear door switch (RH) connector D-08 and ETACS-ECU connector C-226.
NOTE: Also check intermediate connector C-113 and junction block connector C-214. If intermediate connector C-113 or junction block connector C-214 is damaged, repair or replace the connector as described in Harness Connector Inspection.
Q: Is the wiring harness between rear door switch (RH) connector D-08 and ETACS-ECU connector C-226 in good condition?
YES: Replace the ETACS-ECU. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the rear door switch (RH) should be normal.
NO: Repair the wiring harness. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the rear door switch (RH) should be normal.