Inspection Procedure 5
Auto-cruise Control cannot be Set.COMMENT
The fail-safe function is probably canceling auto-cruise control. In this case, scan tool MB991958 can be used to Retest each system by checking the diagnostic trouble codes. The scan tool 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
- Malfunction of the PCM .
DIAGNOSIS
Required Special Tool:
- MB991958: Scan tool (MUT-III sub assembly)
- MB991824: V.C.I.
- MB991827: MUT-III USB cable
- MB991911: MUT-III main harness B
STEP 1. Using scan tool MB991958, read the 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 auto-cruise control system diagnostic trouble code.
4. Turn the ignition switch to the "LOCK" (OFF) position.
5. Disconnect scan tool MB991958.
Q: Is DTC set?
YES: Refer to Diagnostic Trouble Code Chart. Diagnostic Trouble Code Descriptions Then go to Step 6.
NO: Go to Step 2.
STEP 2. Using scan tool MB991958, check data list item 04: 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.
- Item 04, 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 number 4. Then go to Step 6.
STEP 3. Using scan tool MB991958, check data list item 05: Stoplight Switch and data list item 06: 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.
- Item 05, Stoplight 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. Set scan tool MB991958 to data reading mode.
- Item 06, 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".
5. Turn the ignition switch to the "LOCK" (OFF) position.
6. Disconnect scan tool MB991958.
Q: Is the switch operating properly?
YES: Go to Step 4.
NO: Refer to Symptom Procedures number 1. Then go to Step 6.
STEP 4. Using scan tool MB991958, check data list item 07: Clutch pedal position 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.
- Item 07, Clutch pedal position switch
- When clutch pedal is depressed, the display on scan tool MB991958 should be "ON".
- When clutch pedal is released, the display on scan tool MB991958 should be "OFF".
- Item 07, Transmission Range Switch .
- When selector lever is at the "P" or "N" position, the display on scan tool MB991958 should be "ON".
- When selector lever is at the "R" or "D" 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 5
NO: Refer to Symptom Procedures number 3. Then go to Step 6
STEP 5. Check the symptoms.
Q: Can auto-cruise control be set?
YES: It can be assumed that this malfunction is intermittent (Refer to How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction).
NO: Replace the ECM
STEP 6. Check the symptoms.
Q: Can auto-cruise control be set?
YES: The procedure is complete.
NO: Return to Step 1.