Inspection Procedure 12: The stop lamp switch signal is not received.

caution

Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.
When the ETACS-ECU of vehicles without KOS is replaced, the encrypted code of the ignition key needs to be registered to the ETACS-ECU. (If the encrypted code is not registered, the engine cannot be started. Register the encrypted code as described in Immobilizer System - How to Register Key ID .)

COMMENTS ON TROUBLE SYMPTOM

ABS, ASC
Shift lock mechanism
OSS
Cruise control system

PROBABLE CAUSES

Malfunction of stop lamp switch
Malfunction of stop lamp relay^*
Malfunction of ETACS-ECU
Damaged harness wires and connectors

note

^*: The stop lamp relay cannot be inspected because it is a semiconductor relay.

DIAGNOSIS PROCEDURE

STEP 1. Check the stop lamp switch.

Q. Is the check result normal?

STEP 2. Voltage measurement at ETACS-ECU connector (BKLP terminal).

(1)Measure by backprobing without disconnecting the ETACS-ECU connector and stop lamp switch connector.

(2)Check the voltage between the ETACS-ECU connector (BKLP terminal) and body earth.
OK:
When the brake pedal is released: Approximately 0 V - 5 V (pulse)
When the brake pedal is depressed: Approximately system voltage

Q. Is the check result normal?

STEP 3. Check of short to power supply, short to earth, and open circuit in BKLP line between ETACS-ECU connector and stop lamp switch connector.

Q. Is the check result normal?

STEP 4. Check of short to power supply, short to earth, and open circuit in STP line between ETACS-ECU connector and stop lamp switch connector.

Q. Is the check result normal?

STEP 5. M.U.T.-III data list

Item No.	Item name	Normal condition
Item 290	Stop lamp switch	ON

OK: Normal condition is displayed.