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
- The key reminder switch may be defective
- The ETACS-ECU may be defective
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector

DIAGNOSIS

Required Special Tools:
- MB991223: Test Harness Set
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicles communication interface (V.C.I.)
- MB991827: MUT-III USB cable
- MB991911: MUT-III Main harness B




STEP 1. Check key reminder switch connector C-88 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

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

YES: Go to Step 2.

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 key reminder switch should be normal.







STEP 2. 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 3.

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 3. Check the ground circuit to the key reminder switch. Measure the resistance at key reminder switch connector C-88.




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




2. Measure the resistance value between terminal 4 and ground.
- The resistance should equal 2 ohms or less.

Q: Is the measured resistance 2 ohms or less?

YES: Go to Step 5.

NO: Go to Step 4.




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 is necessary and testing is complete.

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 key reminder switch should be normal.




STEP 5. Check ETACS-ECU connector C-117 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is ETACS-ECU connector C-117 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 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: he 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 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.