Inspection Procedure 3

Inspection Procedure 3: ETACS-ECU Does Not Receive Any Signal From The Key Reminder Switch.

Key Reminder Switch Input Circuit:

COMMENTS ON TROUBLE SYMPTOM
The key reminder switch input signal is used for the operation judgment of the functions below. If the signal is abnormal, these functions will not work.
- Ignition key reminder function
- Central door locking
- Keyless entry system
- KOS
- Ignition key cylinder illumination light
- Interior light

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: Harness Set
- MB992006: Extra Fine Probe

STEP 1. Check key reminder switch connector C-211 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q : Is key reminder switch connector C-211 in good condition?

YES : Go to Step 2.

NO : Repair or replace the damaged component(s) (Refer to General (Electrical), Harness Connector Inspection). Check that the input signal of key reminder switch is normal.

STEP 2. Check the key reminder switch.

Disconnect key reminder switch connector C-211. 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. Check that the input signal of key reminder switch is normal.

STEP 3. Check the ground circuit to the key reminder switch. Measure the resistance at key reminder switch connector C-211.

1. Disconnect key reminder switch connector C-211 and measure the resistance available at the wiring harness side of the connector.




2. Measure the resistance value between terminal 2 and ground.
- The resistance should be 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-211 (terminal 2) and ground.

Check the ground wires for open circuit.

Q : Is the wiring harness between key reminder switch connector C-211 (terminal 2) 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. Check that the input signal of key reminder switch is normal.

STEP 5. Check ETACS-ECU connector C-315 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q : Is ETACS-ECU connector C-315 in good condition?

YES : Go to Step 6.

NO : Repair or replace the damaged component(s) (Refer to General (Electrical), Harness Connector Inspection). Check that the input signal of key reminder switch is normal.

STEP 6. Check the wiring harness between key reminder switch connector C-211 (terminal 3) and ETACS-ECU connector C-315 (terminal 13). Check the output lines for open circuit and short circuit.

Q : Is the wiring harness between key reminder switch connector C-211 (terminal 3) and ETACS-ECU connector C-315 (terminal 13) in good condition?

YES : Go to Step 7.

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. Check that the input signal of key reminder switch is normal.

STEP 7. Check for continuity between key reminder switch connector C-211 terminal 2 and each of the other terminals as well as terminal 3 and each of the other terminals.

1. Disconnect key reminder switch connector C-211 and measure the resistance available at the equipment side of the connector.
2. Check for continuity between key reminder switch connector C-211 terminal 2 and each of the other terminals as well as terminal 3 and each of the other terminals.

Q : Does continuity exist between the terminals?

NO : Replace the ETACS-ECU. Check that the input signal of key reminder switch is normal.

YES : Replace the key reminder switch. Check that the input signal of key reminder switch is normal.