INSPECTION PROCEDURE K-1: The tail/stop lamps do not illuminate normally.


caution Whenever the ECU is replaced, ensure that the input and output signal circuits are normal.


COMMENTS ON TROUBLE SYMPTOM
If all the tail/stop lamps do not illuminate, the tail lamp switch input circuit or the front-ECU may be defective.

POSSIBLE CAUSES

  • Malfunction of the column switch
  • Malfunction of the front-ECU
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

Step 1. ECU check by using the SWS monitor.
Check that the power supply and earth lines to the column switch (column-ECU) and the front-ECU and the SWS communication lines are normal.

  • Ignition switch: OFF
ECUS TO BE CHECKED
  • COLUMN ECU
  • FRONT ECU
OK: "OK" are displayed for all the items

Q. Are the check result normal?
"OK" are displayed for all the items : Go to Step 2.
"NG" is displayed on the "COLUMN ECU" menu. : Refer to Inspection Procedure A-2 "Communication with the column switch (column-ECU) is not possible ."
"NG" is displayed on the "FRONT ECU" menu. : Refer to Inspection Procedure A-4 "Communication with the front-ECU is not possible ."

Step 2. Function diagnosis by using the SWS monitor.
Check the SWS communication signal, which are related to the tail lamps.
<Selected item> LIGHTING - TAIL LAMP
  • Ignition switch: ON
  • Lighting switch: TAIL
Item No.
 Item name
 Normal condition
Item 00
 HEADLAMP SW
 ON when the lighting switch is at HEAD
Item 01
 TAIL LAMP SW
 ON when the lighting switch is at TAIL
Item 03
 PASSING SW
 OFF
Item 30
 IG SW(IG1)
 ON
Item 35
 HD AUTO-CUT
 OFF
Item 70
 FRONT ECU ACK
 NORMAL ACK
OK: Normal conditions are displayed for all the items

Q. Are the check result normal?
Normal conditions are displayed for all the items. : Go to Step 3.
Normal condition is not displayed for item 00, 01 or 03. : Refer to inspection procedure P-5 "Column switch (lighting and turn-signal lamp switch) signal is not received ."
Normal condition is not displayed for item No.30. : Refer to inspection procedure P-2 "The ignition switch (IG1) signal is not received ."
Normal condition is not displayed for item No.35. : Refer to Inspection Procedure K-5 "The headlamp automatic-shutdown function does not work normally ."
Normal condition is not displayed for item No.70. : Replace the front-ECU.

Step 3. Connector check: A-14X front-ECU connector.

Q. Is the check result normal?

Go to Step 4.

Repair the defective connector.

Step 4. Voltage measurement at the A-14X front-ECU connector.

(1)Remove the front-ECU, and measure at the relay box side.

(2)Voltage between A-14X front-ECU connector terminal No.5 and body earth
OK: System voltage

Q. Is the check result normal?

Go to Step 6.

Go to Step 5.

Step 5. Check the wiring harness between A-14X front-ECU connector terminal No.5 to the fusible link (26).

  • Check the power supply line 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 6. Retest the system.
Check that the tail/stop lamps illuminate normally.

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 front-ECU.