Inspection Procedure O-3

Key Reminder Switch Input Circuit:

CIRCUIT OPERATION
The ETACS-ECU operates various functions according to the input signal from the key reminder switch.

TECHNICAL DESCRIPTION (COMMENT)
The key reminder switch input signal is used to operate the following functions or system. If the signal fails, these functions or system will not work normally.
- Ignition key tone alarm function
- Forgotten key prevention function
- Keyless entry system
- Dome light dimming function
- Theft-alarm system

TROUBLESHOOTING HINTS
- Malfunction of the key reminder switch
- Malfunction of the ETACS-ECU
- Damaged harness wires or connectors

DIAGNOSIS
Required Special Tools:
MB991223: Test Harness Set
MB991502: Scan Tool (MUT-II)
MB991529: Diagnostic Trouble Code Check Harness

STEP 1. Check the key reminder switch.
Disconnect key reminder switch connector C-88. Then check the continuity.
If the key reminder switch is damaged, repair it.
The key reminder switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.
If the key reminder switch is in good condition, go to Step 2.

STEP 2. Check the key reminder switch ground circuit at the key reminder switch connector C-88.
1. Disconnect the key reminder switch connector C-88 and measure at the harness side.
2. Resistance between terminal 4 and ground.
- Should be less than 2 Ohms.
If open circuit, go to Step 3.
If less than 2 Ohms. go to Step 5.

STEP 3. Check the key reminder switch connector C-88 for damage.
If the key reminder switch connector C-88 is damaged, repair or replace it. Refer to Harness Connector Inspection.
The key reminder switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.
If the connector is in good condition, go to Step 4.

STEP 4. Check the harness wire between key reminder switch connector C-88 and ground.
If the harness wire between key reminder switch connector C-88 and ground is damaged, repair it.
The key reminder switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.

STEP 5. Check the key reminder switch connector C-88 and ETACS-ECU connector C-111 for damage.
If the key reminder switch connector C-88 and ETACS-ECU connector C-111 are damaged, repair or replace them. Refer to Harness Connector Inspection. The key reminder switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.
If the connectors are in good condition, go to Step 6.

STEP 6. Check the harness wire between key reminder switch connector C-88 and ETACS-ECU connector C-111.
If the harness wire between key reminder switch connector C-88 and ETACS-ECU connector C-111 is damaged, repair it.
The key reminder switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.
If the harness wire is in good condition, replace the ETACS-ECU.
The key reminder switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.