Inspection Procedure 5
INSPECTION PROCEDURE 5: Auto-cruise Control System cannot be Set.COMMENT
The fail-safe function is probably canceling auto-cruise control system. In this case, checking the diagnostic trouble codes. The scan tool MB991958 can also be used to check if the circuits of each input switch are normal or not by checking the input switch codes.
TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CASE)
- Malfunction of the auto-cruise control switch.
- Malfunction of the stoplight switch.
- Malfunction of the transmission range switch.
- Malfunction of the ECM
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. Read the diagnostic trouble code.
Read the auto-cruise control system diagnostic trouble code.
Q: Is DTC set?
YES: Diagnose the auto-cruise control system. (Refer to Diagnostic Trouble Code Chart). Then go to Step 7. Diagnostic Trouble Code Descriptions
NO: Go to Step 2.
STEP 2. Using scan tool MB991958, check data list item 75: Cancel 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 75, Cancel switch.
- When "CANCEL" switch is at the ON position, the display on scan tool MB991958 should be "ON".
- When "CANCEL" switch is at the OFF 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: Refer to Symptom Procedures - Inspection Procedure 4. Then go to Step 7. Inspection Procedure 4
STEP 3. Using scan tool MB991958, check data list item 74: Brake light switch and data list item 89: Normally closed brake 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 74, Brake light switch.
- When brake pedal is depressed, the display on scan tool MB991958 should be "ON".
- When brake pedal is released, the display on scan tool MB991958 should be "OFF".
- Item 89, Normally closed brake switch.
- When brake pedal is depressed, the display on scan tool MB991958 should be "ON".
- When brake pedal is released, 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 4
NO: Refer to Symptom Procedures - Inspection Procedure 1. Then go to Step 7. Inspection Procedure 1
STEP 4. Using scan tool MB991958, check data list item 78: Clutch 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 78: Clutch switch.
- When the clutch pedal is depressed, the display on scan tool MB991958 should be "ON".
- When the clutch pedal is released, 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 6.
NO: Refer to Symptom Procedures - Inspection Procedure 2. Then go to Step 7. Inspection Procedure 2
STEP 5. 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 6.
NO: Refer to Symptom Procedures - Inspection Procedure 3. Then go to Step 7. Inspection Procedure 3
STEP 6. Check the symptoms.
Q: Can auto-cruise control be set?
YES: It can be assumed that this malfunction is intermittent.
NO: Replace the ECM
STEP 7. Check the symptoms.
Q: Can auto-cruise control be set?
YES: The procedure is complete.
NO: Return to Step 1.