Inspection Procedure 6

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

CAUTION:
Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.

TECHNICAL DESCRIPTION (COMMENT)

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.

TROUBLESHOOTING HINTS

- Damaged wiring harness or connector (short to ground in PDSW line)
- Malfunction of selector lever assembly (ON seizure of P range detection switch)
- Malfunction of OSS-ECU

DIAGNOSIS

STEP 1. Using scan tool MB991958, read the diagnostic trouble code

(1)
CAUTION:
To prevent damage to scan tool (MB991958), always turn the power supply mode of the engine switch to the OFF position before connecting or disconnecting scan tool (MB991958).

Connect scan tool MB991958. Refer to "How to connect scan tool (M.U.T.-III) Reading and Clearing Diagnostic Trouble Codes."

(2)After performing the forced power supply output (refer to forced power supply output procedure Programming and Relearning) "IG-ON".

(3)Check if the DTC is set to OSS-ECU.

(4)Turn the power supply mode of the engine switch to OFF.

Q. Is the DTC set?

YES Diagnose the OSS. Refer to diagnostic trouble code chart Keyless Operation System (KOS).

NO Go to Step 2.

STEP 2. Check of short to ground 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?

YES Go to Step 3.

NO 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.






Q. Is the check result normal?

YES Go to Step 4.

NO Replace the selector lever assembly.

STEP 4. Using scan tool MB991958, check data list.

Check the OSS-ECU data list.

- Operate the selector lever.





OK: Operation state and data list display agree with each other.

Q. Is the check result normal?

YES Intermittent malfunction is suspected How to Cope With Intermittent Malfunctions).

NO Replace the OSS-ECU and register the VIN (Refer to Programming and Relearning).