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DTC C1705 LDW SW circuit low (short)
 
 
caution
  • Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
 
 
DIAGNOSTIC FUNCTION
When the FCM/LDW/AHB-ECU receives "ON" signal from the LDW switch for at least one minute consecutively, DTC C1705 will be set.
 
 
TROUBLE JUDGMENT
The FCM/LDW/AHB-ECU receives a signal from the LDW switch via CAN communication with the ETACS-ECU. When the ECU receives "ON" signal from the LDW switch for at least one minute consecutively, it determines that the system is defective.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the LDW switch (Stuck on)
  • Malfunction of the FCM/LDW/AHB-ECU
  • The ETACS-ECU may be defective
  • Damaged harness wires and connectors
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Using scan tool (M.U.T.-IIISE), check data list.
Check the ETACS-ECU data list (Refer to ).
(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 Scan Tool (M.U.T.-IIISE) ."
(2) Check the input signals from the LDW switch.
  • When the LDW switch is pressed.
 
Item No.Item nameNormal condition
109LDW switchON
Item No.Item nameNormal condition
109LDW switchON
  • When the LDW switch is not pressed.
 
Item No.Item nameNormal condition
109LDW switchOFF
Item No.Item nameNormal condition
109LDW switchOFF
OK: Normal condition is displayed.
Is the check result normal?
Go to Step 2.
: Go to Step 4.
 
STEP 2. Using scan tool (M.U.T.-IIISE), check data list.
Check the input signal from the FCM/LDW/AHB-ECU(Refer to ).
  • When the LDW switch is pressed.
 
Item No.Item nameNormal condition
26LDW switchON
Item No.Item nameNormal condition
26LDW switchON
  • When the LDW switch is not pressed.
 
Item No.Item nameNormal condition
26LDW switchOFF
Item No.Item nameNormal condition
26LDW switchOFF
OK: Normal condition is displayed.
Is the check result normal?
Go to Step 3.
Replace the FCM/LDW/AHB-ECU (Refer to ).
 
STEP 3. Using scan tool (M.U.T.-IIISE), read the DTC again.
Check again if the DTC is set in the FCM/LDW/AHB-ECU.
(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) Check if DTC is set.
Is the DTC set?
Replace the FCM/LDW/AHB-ECU (Refer to ).
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
 
STEP 4. Check of short to ground circuit in LDWS line between ETACS-ECU connector and LDW switch connector.
Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.
 
STEP 5. Check the LDW switch.
Check the LDW switch (Refer to ).
Is the check result normal?
Go to Step 6.
Replace the LDW switch (Refer to ).
 
STEP 6. Using scan tool (M.U.T.-IIISE), check data list.
Check the ETACS-ECU data list (Refer to ).
  • When the LDW switch is pressed.
 
Item No.Item nameNormal condition
109LDW switchON
Item No.Item nameNormal condition
109LDW switchON
  • When the LDW switch is not pressed.
 
Item No.Item nameNormal condition
109LDW switchOFF
Item No.Item nameNormal condition
109LDW switchOFF
OK: Normal condition is displayed.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
: Replace the FCM/LDW/AHB-ECU (Refer to ).