Inspection Procedure P-8

The ETACS-ECU does not Receive a Signal from Hood Switch.

Hood Switch Input Circuit Part 1:

Hood Switch Input Circuit Part 2:

CIRCUIT OPERATION
The ETACS-ECU operates the theft-alarm system according to signal from the hood switch.

TECHNICAL DESCRIPTION (COMMENT)
If the signal is not normal, the theft-alarm system does not work normally.

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

DIAGNOSIS

Required Special Tools:
- MB991223: 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 hood switch.
Remove the hood switch. Refer to Hood. Then check continuity between the switch terminals.

Q: Is the hood switch in good condition?

YES: Go to Step 2.

NO: Replace the hood switch. If the theft-alarm system operates normally, it indicates that a correct signal is sent from the hood switch.

STEP 2. Measure at hood switch connector A-23 in order to check the ground circuit to the hood switch.




1. Disconnect hood switch connector A-23, and measure at the wiring harness side.




2. Measure the resistance value between terminal 1 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 hood switch connector A-23 for damage.

Q: Is hood switch connector A-23 in good condition?

YES: Go to Step 4.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. If the theft-alarm system operates normally, it indicates that a correct signal is sent from the hood switch.




STEP 4. Check the wiring harness between hood switch connector A-23 (terminal 1) and ground.

Q: Is the wiring harness between hood switch connector A-23 (terminal 1) and the ground in good condition?

YES: No action to be taken.

NO: Repair the wiring harness. If the theft-alarm system operates normally, it indicates that a correct signal is sent from the hood switch.







STEP 5. Check hood switch connector A-23 and ETACS-ECU connector C-117 for damage.

Q: Are hood switch connector A-23 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 theft-alarm system operates normally, it indicates that a correct signal is sent from the hood switch.










STEP 6. Check the wiring harness between hood switch connector A-23 (terminal 2) and ETACS-ECU connector C-117 (terminal 24).

NOTE: Also check intermediate connector C-89. If intermediate connectors C-89 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Is the wiring harness between hood switch connector A-23 (terminal 2) and ETACS-ECU connector C-117 (terminal 24) in good condition?

YES: Replace the ETACS-ECU. If the theft-alarm system operates normally, it indicates that a correct signal is sent from the hood switch.

NO: Repair the wiring harness. If the theft-alarm system operates normally, it indicates that a correct signal is sent from the hood switch.