Inspection Procedure 19: Back-up lamp switch system <M/T>








OPERATION



  • A backup lamp switch detects that a transmission is shifted into a reverse gear position.
  • An engine-ECU controls an engine speed to be 3000r/min or less so that an excessive load cannot be applied to a drive train system due to a sudden start in a reverse gear position.

PROBABLE CAUSES



  • Failed back-up lamp switch
  • Damaged harness (Open circuit between back-up lamp switch and engine-ECU, and open circuit between back-up lamp switch and ignition switch)
  • Damaged connector (Engine-ECU connector, back-up lamp switch connector)
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

  • Refer to Data List Reference Table .

  1. Item 73: Reverse shift switch

Q. Is the check result normal?
Go to Step 7 .
Go to Step 2 .

STEP 2. Check back-up lamp switch itself

  • Check back-up lamp switch itself (Refer to GROUP 22B - Transmission - Transmission Inspection ).

Q. Is the check result normal?
Go to Step 3 .
Replace the back-up lamp switch.

STEP 3. Connector check: C-17 back-up lamp switch connector

Q. Is the check result normal?
Go to Step 4 .
Repair or replace.

STEP 4. Perform voltage measurement at C-17 back-up lamp switch connector.

  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 2 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 5 .
Check intermediate connectors D-225, D-229, D-401, D-403, and repair if necessary. If intermediate connectors are normal, check and repair harness between C-17 (terminal No. 2) back-up lamp switch connector and D-309 (terminal No. 2) ignition switch connector.

STEP 5. Connector check: D-213 engine-ECU connector

Q. Is the check result normal?
Go to Step 6 .
Repair or replace.

STEP 6. Perform voltage measurement at D-213 engine-ECU connector.

  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 9 and earth.
OK:
    System voltage (Shift lever position: Reverse)
    0 V (Shift lever position: Neutral)

Q. Is the check result normal?
Go to Step 7 .
Check intermediate connector D-225, and repair if necessary. If intermediate connector is normal, check and repair harness between D-213 (terminal No. 9) engine-ECU connector and C-17 (terminal No. 1) back-up lamp switch connector.

STEP 7. Check the trouble symptoms.

Q. Does trouble symptom persist?
Replace the engine-ECU. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - Precautions Before Service - How to Perform Chassis Number Writing ). After replacing the engine-ECU, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ). After registering the injector identification code, the vehicle equipped with the closed type DPF carries out the forcible DPF regeneration. (Refer to GROUP 17 - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).