Inspection Procedure 3

INSPECTION PROCEDURE 3: When the Selector Lever is Moved to "N" Position, Auto-cruise Control System is not Cancelled .

Transmission Range Switch Circuit Part 1:

Transmission Range Switch Circuit Part 2:

Transmission Range Switch Circuit Part 3:

CIRCUIT OPERATION
- Battery positive voltage is applied to the transmission range switch (terminal 8) when the ignition switch is turned "ON."
- Battery positive voltage is applied to the PCM terminal 77 when the selector lever is in the "N" range. The PCM judges that the selector lever is in the "N" range when the battery positive voltage is applied.

COMMENT
The transmission range switch circuit is suspected.

TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CASE)
- Malfunction of the transmission range switch.
- Damaged harness or connector.
- Malfunction of the PCM.

DIAGNOSIS

Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, check data list item 88: Neutral switch.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991958 to data reading mode for auto-cruise control system.
- Item 88, Neutral switch.
- When selector lever is at the "N" position, the display on scan tool MB991958 should be "ON".
- When selector lever is other than "N" position, the display on scan tool MB991958 should be "OFF".

4. Turn the ignition switch to the "LOCK" (OFF) position.
5. Disconnect scan tool MB991958.

Q: Is the switch operating properly?

YES: Go to Step 3.

NO: Go to Step 2.




STEP 2. Using scan tool MB991958, read the A/T system diagnostic trouble code.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Check for A/T system diagnostic trouble code. (Refer to A/T Diagnosis - Diagnostic Function - How to Read and Erase Diagnostic Trouble Code).
4. Turn the ignition switch to the "LOCK" (OFF) position.
5. Disconnect scan tool MB991958.

Q: Is any DTC P1770 or P1771 set?

YES: Refer to A/T Diagnosis - Diagnostic Trouble Code Procedures - DTC P1770: Transmission Range Switch System (Open Circuit) DTC P1771: Transmission Range Switch System (Short Circuit). Then go to Step 4.

NO: Go to Step 3.

STEP 3. Check the symptoms.

Q: When the selector lever is moved to "N" position, auto-cruise control system is cancelled?

YES: It can be assumed that this malfunction is intermittent.

NO: Replace the PCM. Then go to Step 4.

STEP 4. Check the symptoms.

Q: When the selector lever is moved to "N" position, auto-cruise control system is cancelled?

YES: The procedure is complete.

NO: Return to Step 1.