Inspection Procedure 6: Vehicle power cannot be turned OFF when the shift position is in "P." (Power supply mode ON to ACC is possible)


caution Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.

COMMENTS ON TROUBLE SYMPTOM


When the shift position is judged to be in the P position based on the input of P range detection switch, OSS-ECU can turn OFF the vehicle power supply. If the vehicle power cannot be turned OFF (power supply mode ON to ACC is possible) when the shift is in P position, the P range detection switch or OSS-ECU may have a problem.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE


STEP 1. M.U.T.-III diagnosis code


Check if the diagnosis code is set to OSS-ECU.

Q. Is the diagnosis code set?

Diagnose the OSS-ECU. Refer to .

Go to Step 2.

STEP 2. Check of short to earth in PDSW line between selector lever assembly connector and OSS-ECU connector


note Because the conformity cannot be determined even when the digital tester is used to measure the voltage of PDSW line between the selector lever assembly connector and OSS-ECU connector, be sure to use the oscilloscope. (Outputs the sawtooth waveform of 0 to 5 V with intervals of 10 ms.)

Q. Is the check result normal?

Go to Step 3.

Repair the connector(s) or wiring harness.

STEP 3. Check of selector lever assembly (P range detection switch)


Disconnect the selector lever assembly connector, and check the continuity at the equipment side.
Terminal No.
 Operation state
 Normal conditions
4 - 6
 Selector lever: P position
 No continuity
Selector lever: Other than P position
 Continuity exists (2 Ω or less)

Q. Is the check result normal?

Go to Step 4.

Replace the selector lever assembly.

STEP 4. M.U.T.-III data list


Check the OSS-ECU data list.

Operation state
 Item No.
 Check item
 Display
Selector lever: P position
 8
 P range detect SW
 Outside park
Selector lever: Other than P position
 Park
OK: Operation state and data list display agree with each other.

Q. Is the check result normal?

Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).

Replace the OSS-ECU and register the chassis number (Refer to ).