7. Key Reminder Function (Door Lock Prevention) Doesn't Operate
CIRCUIT OPERATION
When any of the doors is opened or closed, the ETACS-ECU will output the door switch ON or OFF signal for 0.5 second If the key is inserted or removed, the ETACS-ECU will output the key reminder switch ON or OFF signal for 0.5 second.
TECHNICAL DESCRIPTION
The cause may be a malfunction of the door switch and key reminder switch circuit or of the ground circuit.
TROUBLESHOOTING HINTS
- Malfunction of the door switch
- Malfunction of the ETACS-ECU
- Malfunction of the key reminder switch
- Damaged harness wires or connectors
DIAGNOSIS
Required Special Tools:
MB991502: Scan Tool (MUT-II)
MB991529: Diagnostic Trouble Code Check Harness
CAUTION: To prevent damage to the scan tool MB991502, make sure the ignition switch is "OFF" before connecting or disconnecting the scan tool MB991502.
STEP 1. Check the ETACS-ECU input signal. Using either the scan tool or a voltmeter
- Using the scan tool MB991502
1. Connect scan tool MB991502 to the data link connector.
2. If the tone alarm of scan tool MB991502 sounds once when any door opens/closes (door switch ON/OFF) or the key is removed/inserted (key reminder switch ON/OFF), the ETACS-ECU input signal for those switch circuit systems are normal.
- Using a voltmeter
1. Use special tool MB991529 to connect a voltmeter between ground terminal 4 or 5 and the ETACS-ECU terminal of the data link connector.
2. If a voltmeter indicator deflects once when any door opens/closes (door switch ON/OFF) or the key removes/inserts (key reminder switch ON/OFF), the ETACS-ECU input signal for those switch circuit systems are normal
If the input signal of the door switch is not normal, go to Step 2.
If the input signal of the key reminder switch is not normal, go to Step 3.
STEP 2. Check the door switch continuity.
1. Remove the door switch.
2. Check the continuity when the door switch is depressed (OFF) or undepressed (ON).
If the door switch is damaged, replace it. Then go to Step 8.
If the door switch is not damaged, go to Step 4.
STEP 3. Check the key reminder switch continuity
1. Remove the column cover and then disconnect the key reminder switch connector.
2. Check the continuity when the key is removed or installed.
If the key reminder switch is damaged, replace it. (Refer to - Ignition switch.) Then go to Step 8.
If the key reminder switch is not damaged, go to Step 5.
STEP 4. Check the harness wires between ETACS-ECU connector C-86 and door switch connector D-08 (front [RH]), D-21 (front [LH]), F-08 (rear [RH]) or F-14 (rear [LH]).
1. Remove the ETACS-ECU
2. Connect the connectors C-78 and C-87 to the junction block.
3. Check the harness wires between ETACS-ECU connector C-86 and door switch connector D-08 (front [RH]), D-21 (front [LH]), F-08 (rear [RH]) or F-14 (rear [LH]).
If any harness wire between ETACS-ECU connector 0-86 and door switch D-08 (front [RH]), D-21 (front [LH]), F-08 (rear [RH]) or F-14 (rear [LH]) is damaged, repair it. Then go to Step 6.
If the harness wires are not damaged, go to Step 6.
NOTE: After inspecting intermediate connector C-69, C-78 or D-07, inspect the wire. If intermediate connector C-69 C-78 or D-07 is damaged, repair or replace it. Refer to Harness Connector Inspection. Then go to Step 8.
STEP 5. Check the harness wires between ETACS-ECU connector C-82 and key reminder switch connector C-59.
1. Remover the instrument panel side cover [LH].
2. Check the harness wires between ETACS-ECU connector C-82 and key reminder switch connector C-59.
If any harness wire between ETACS-ECU connector C-82 and key reminder switch connector C-59 is damaged, repair it. Then go to Step 8.
If the harness wires are not damaged, go to Step 7.
STEP 6. Check the harness wires between door switch connector D-08 (front [RH]), D-21 (front [LH]), F-08 (rear [RH]) or F-14 (rear [LH]) and ground.
If any harness wire between door switch connector D-08 (front [RH]), D-21 (front [LH]), F-08 (rear [RH]) or F-14 (rear [LH]) and ground is damaged, repair it.
Then go to Step 8.
If the harness wires are not damaged, replace the ETACS-ECU. Then go to Step 8.
STEP 7. Check the harness wires between key reminder switch connector C-59 and ground.
If any harness wire between key reminder switch connector C-59 and ground is damaged, repair it.
Then go to Step 8.
If the harness wires are not damaged, replace the ETACS-ECU. Then go to Step 8.
STEP 8. Check symptoms.
Confirm that the intermediate connectors, the harness wires, the door switch, the key reminder switch, and the ETACS-ECU are normal.