Inspection Procedure P-1

ETACS-ECU does not Receive a Signal from the Key Reminder Switch.

Key Reminder Switch Input Circuit:

CIRCUIT OPERATION
The ETACS-ECU operates the following functions or systems according to signal from the key reminder switch:
- Ignition key reminder tone alarm function
- Keyless entry system
- Dome light dimming function

TECHNICAL DESCRIPTION (COMMENT)
If the signal is not normal, the functions or systems, which are described in "CIRCUIT OPERATION", do not work normally.

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
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicles communication interface
- MB991827: MUT-III USB cable
- MB991911: MUT-III Main harness B







STEP 1. Check the key reminder switch.
Disconnect key reminder switch connector C-88. Then check continuity between terminals.

Q: Is the key reminder switch in good condition?

YES: Go to Step 2.

NO: Replace the key reminder switch. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the key reminder switch should be normal.

STEP 2. Measure at key reminder switch connector C-88 in order to the ground circuit to the key reminder switch.




1. Disconnect key reminder switch connector C-88, and measure at the wiring harness side.




2. Measure the resistance value between terminal 4 and ground.
- The measured value should be 2 ohm or less.

Q: Does the measured resistance value correspond with this range?

YES: Go to Step 5.

NO: Go to Step 3.




STEP 3. Check key reminder switch connector C-88 for damage.

Q: Is key reminder switch connector C-88 in good condition?

YES: Go to Step 4.

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 key reminder switch should be normal.




STEP 4. Check the wiring harness between key reminder switch connector C-88 (terminal 4) and ground.

Q: Is the wiring harness between key reminder switch connector C-88 (terminal 4) and ground in good condition?

YES: No action to be taken.

NO: Repair the wiring harness. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the key reminder switch should be normal.







STEP 5. Check key reminder switch connector C-88 and ETACS-ECU connector C-117 for damage.

Q: Are key reminder switch connector C-88 and ETACS-ECU connector C-117 in good condition?

YES: Go to Step 6.

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 key reminder switch should be normal.







STEP 6. Check the wiring harness between key reminder switch connector C-88 (terminal 6) and ETACS-ECU connector C-117 (terminal 30).

Q: Is the wiring harness between key reminder switch connector C-88 (terminal 6) and ETACS-ECU connector C-117 (terminal 30) in good condition?

YES: Go to Step 7.

NO: Repair the wiring harness. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the key reminder switch should be normal.

STEP 7. Check continuity between every two terminals other than key reminder switch connector C-88 terminals 4 and 6.

1. Measure at key reminder switch connector C-88 without disconnecting the connector.




2. No continuity should be present between key reminder switch terminal 4 and each terminal other than terminal 6, and between key reminder switch terminal 6 and each terminal other than terminal 4.

Q: Is continuity present between any two terminals?

YES: Replace the ETACS-ECU. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the key reminder switch should be normal.

NO: Replace the key reminder switch. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the key reminder switch should be normal.