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DTC C1750 Voltage out of range
 
 
caution
  • Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
 
 
OPERATION
FCM/LDW/AHB-ECU power supply is provided from the battery.
 
 
DIAGNOSTIC FUNCTION AND TROUBLE JUDGMENT
This DTC is set when the abnormality below is detected:
  • Voltage between the battery: Less than 10.0 volts
  • Voltage between the battery: More than 16.0 volts
 
 
TROUBLESHOOTING HINTS
  • Battery failure
  • Loose battery terminal
  • Malfunction of charging system
  • Malfunction of the FCM/LDW/AHB-ECU power supply circuit
  • Malfunction of the FCM/LDW/AHB-ECU
  • Damaged harness wires and connectors
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Check the battery.
Refer to Battery Test .
Is the check result normal?
Go to Step 2
Charge or replace the battery.
 
STEP 2. Check the charging system.
Refer to GROUP 16 - Charging System .
Is the check result normal?
Go to Step 3
Repair or replace the charging system component(s).
 
STEP 3. Check of open circuit in GND line between FCM/LDW/AHB-ECU connector and body ground.
Is the check result normal?
Go to Step 4
Repair the connector(s) or wiring harness.
 
STEP 4. Voltage measurement at FCM/LDW/AHB-ECU connector (IG terminal).
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) Check the voltage between the FCM/LDW/AHB-ECU connector (IG terminal) and body ground.
OK: Is the measured voltage approximately 12 volts (battery positive voltage)
Is the check result normal?
Go to Step 5
Go to Step 6
 
STEP 5. 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)
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) Erase the DTC.
(3) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(4) Check if the 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 6. Check of short to ground, and open circuit in IG line between fusible link and FCM/LDW/AHB-ECU connector.
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 ).
Repair the connector(s) or wiring harness.