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DTC C1705: LDW SW circuit low (short)
 
 
cautionBefore 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 No. C1705 will be set.
 
 
DTC SET CONDITION
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
  • The LDW switch may be defective (Stuck on)
  • The FCM/LDW/AHB-ECU may be defective
  • The ETACS-ECU may be defective
  • The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Using scan tool (M.U.T.-IIISE), check data list.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn off the power supply mode of the electric motor switch 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 ETACS-ECU data list (Refer to ).
  • When the LDW switch is pressed.
 
Item No.Item nameNormal condition
405LDW switchON
  • When the LDW switch is not pressed.
 
Item No.Item nameNormal condition
405LDW 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 (Refer to ).
  • When the LDW switch is pressed.
 
Item No.Item nameNormal condition
26LDW switchON
  • When the LDW switch is not pressed.
 
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. Check whether the DTC is set again.
Check again if the DTC is set in the FCM/LDW/AHB-ECU.
(1) Erase the DTC.
(2) Press the electric motor switch to turn the power supply mode from "OFF" to "ON."
(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
405LDW switchON
  • When the LDW switch is not pressed.
 
Item No.Item nameNormal condition
405LDW 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 ETACS-ECU.