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 3, 000 r/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 J/B)
  • 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 <2WD>, GROUP 22C - Transmission - Transmission Inspection <4WD>).

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

STEP 3. Connector check: B-02 back-up lamp switch connector

Q. Is the check result normal?

Go to Step 4.

Repair or replace.

STEP 4. Perform voltage measurement at B-02 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 connector C-30, and repair if necessary. If intermediate connector is normal, check and repair harness between B-02 (terminal No. 2) back-up lamp switch connector and C-208 (terminal No. 2) connector.

STEP 5. Connector check: C-105 engine-ECU connector

Q. Is the check result normal?

Go to Step 6.

Repair or replace.

STEP 6. Perform voltage measurement at C-105 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 connectors A-28 and C-29, and repair if necessary. If intermediate connectors are normal, check and repair harness between C-105 (terminal No. 9) engine-ECU connector and B-02 (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 DPF carries out the forcible DPF regeneration. (Refer to GROUP 17 - Emission Control - 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 ).