INSPECTION PROCEDURE P-20: The interior lamp "all on" or "all off" switch signal is not sent to the ETACS-ECU.


caution Whenever the ECU is replaced, ensure that the input signal circuit is normal.


COMMENTS ON TROUBLE SYMPTOM
Input signals from the interior lamp switches are used to operate the interior lamps. If the signals are abnormal, the interior lamps will not illuminate and extinguish normally.

POSSIBLE CAUSES

  • Malfunction of the room lamp
  • Malfunction of the ETACS-ECU
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

Step 1. Connector check: E-02 room lamp connector




Q. Is the check result normal?

Go to Step 2.

Repair the defective connector.

Step 2. Check the room lamp.
Refer to GROUP 54A - Room lamp .

Q. Is the check result normal?
Go to Step 3
Replace the room lamp.

Step 3. Resistance measurement at the E-02 room lamp connector




(1)Disconnect the connector, and measure at the wiring harness side.

(2)Resistance between E-02 room lamp connector terminal No.5 and body earth
OK: 2 Ω or less

Q. Is the check result normal?

Go to Step 5.

Go to Step 4.

Step 4. Check the wiring harness between E-02 room lamp connector terminal No.5 and body earth






note Prior to the wiring harness inspection, check intermediate connector E-11, and repair if necessary.

  • Check the earth wires for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

Repair the wiring harness.

Step 5. Connector check: C-221 ETACS-ECU connector


Q. Is the check result normal?

Go to Step 6.

Repair the defective connector.

Step 6. Check the wiring harness from E-02 room lamp connector terminal Nos. 6 and 7 to C-221 ETACS-ECU connector terminal Nos. 53 and 63.










note Prior to the wiring harness inspection, check intermediate connector E-11 and C-128, and repair if necessary.

  • Check the input line for open circuit.

Q. Is the check result normal?

Go to Step 7.

Repair the wiring harness.

Step 7. ETACS switch data by using the SWS monitor
Check the input signal from the interior lamp switch.

  • Interior lamp switch: from ON to OFF
Item No.
 Item name
 Normal condition
Item 31
 RM LMP ON SW
 from ON to OFF
Item 32
 RM LMP OFF SW
 from OFF to ON
OK: Normal condition is displayed.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Replace the ETACS-ECU.