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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 12V Starter Battery.
 
 
DTC SET CONDITIONS
This DTC is set when the abnormality below is detected:
  • Voltage between the 12V Starter Battery: Less than 10.0 V
  • Voltage between the 12V Starter Battery: More than 16.0 V
 
 
TROUBLESHOOTING HINTS
  • 12V Starter Battery failure
  • Loose 12V Starter Battery terminal
  • 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 12V Starter Battery.
Refer to GROUP 54A - 12V Starter Battery Test .
Is the check result normal?
Go to Step 2
Charge the 12V Starter Battery.
 
STEP 2. Check of open circuit in GND line between FCM/LDW/AHB-ECU connector and body ground.
Is the check result normal?
Go to Step 3
Repair the connector(s) or wiring harness.
 
STEP 3. Voltage measurement at FCM/LDW/AHB-ECU connector (IG terminal).
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Turn off the power supply mode of the electric motor switch.
(3) Turn on the power supply mode of the electric motor switch.
(4) Check the voltage between the FCM/LDW/AHB-ECU connector (IG terminal) and body ground.
OK: System voltage
Is the check result normal?
Go to Step 4
Go to Step 5
 
STEP 4. Check whether the DTC is set again.
(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 the Scan Tool (M.U.T.-IIISE) ."
(2) Turn on the power supply mode of the electric motor switch.
(3) Erase the DTC.
(4) Turn off the power supply mode of the electric motor switch.
(5) Turn on the power supply mode of the electric motor switch.
(6) 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 5. 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.