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Inspection Procedure 2: When The ACC ON/OFF Switch is Operated, The System is not Turned ON.
 
 
cautionWhen the ACC/FCM-ECU is replaced, calibrate the radar (refer to ).
 
 
OPERATION
This circuit judges the signals of each switches (ACC ON/OFF, CANCEL, SET - and RES +) of the cruise control switch. The ECM detects the state of the cruise control switches by sensing the voltages shown below.
  • When all switches are released: 4.7 - 5.0 volts
  • When the ACC ON/OFF switch is pressed: 0.9 - 1.7 volt
  • When the CANCEL switch is pressed: 1.9 - 2.7 volts
  • When the SET - switch is pressed: 2.9 - 3.6 volts
  • When the RES + switch is pressed: 3.8 - 4.5 volts
 
 
COMMENTS ON TROUBLE SYMPTOM
The scan tool (M.U.T.-IIISE) can also be used to check if the circuits of each input switches are normal or not by checking the data list.
notePress the cruise control switches one by one securely. Otherwise, the adaptive cruise control system may not be started.
 
 
PROBABLE CAUSES
  • Damaged harness or connector
  • Malfunction of the clock spring
  • Malfunction of the cruise control switch (integrated with ACC ON/OFF switch)
  • Malfunction of the ECM
  • Malfunction of the ACC/FCM-ECU
 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-IIISE), check the DFI and MFI system data list.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
(2) Turn the ignition switch to the "ON" position.
(3) Using scan tool (M.U.T.-IIISE), check the DFI and MFI system data list (Refer to GROUP 13A - Diagnosis, Data List Reference Table ).
  • Item No.75: Cancel switch
  • Item No.86: Cruise control ON/OFF switch
  • Item No.91: Resume switch
  • Item No.92: Set switch
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the check result normal?
Go to Step 8.
Go to Step 2.
 
STEP 2. Check the cruise control switch (integrated with ACC ON/OFF switch).
Refer to .
Is the check result normal?
Go to Step 3.
Replace the cruise control switch (integrated with ACC ON/OFF switch) (Refer to ).
 
STEP 3. Check of short to ground, and open circuit in CNTS line between ECM connector and clock spring connector.
Is the check result normal?
Go to Step 4.
Repair the connector(s) or wiring harness.
 
STEP 4. Check of open circuit in SW- line between ECM connector and clock spring connector.
Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.
 
STEP 5. Check of short to ground, and open circuit in CNTS line between clock spring connector and cruise control switch connector.
Is the check result normal?
Go to Step 6.
Repair the connector(s) or wiring harness.
 
STEP 6. Check of open circuit in SW- line between clock spring connector and cruise control switch connector.
Is the check result normal?
Go to Step 7.
Repair the connector(s) or wiring harness.
 
STEP 7. Check the clock spring.
Refer to GROUP 52B - Driver’s Air Bag Module and Clock Spring Inspection .
Is the check result normal?
Replace the ECM (Refer to GROUP 13A - ECM ).
Replace the clock spring, and install the driver’s air bag module [Refer to GROUP 52B - Driver’s Air Bag Module and Clock Spring ].
 
STEP 8. Check the cruise control function.
Press the ACC ON/OFF switch on the cruise control switch for 1.5 seconds or more. Then check that the cruise control system turned ON (the cruise control display screen is turned on).
Is the check result normal?
Go to Step 9.
Replace the ECM (Refer to GROUP 13A - ECM ).
 
STEP 9. Check the symptom.
Is the system turned on by operating the ACC ON/OFF switch?
It can be assumed that this malfunction is intermittent (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points, How to Cope with Intermittent Malfunction ).
Replace the ACC/FCM-ECU (Refer to ).