Code No. C1750:
FCM voltage out of range
DIAGNOSTIC FUNCTION
If the laser radar detects that the ECU power supply voltage is less than 8.5 V or more
than 16.5 V, diagnosis code No. C1750 is set.
CHECK CONDITION
When all the following conditions are satisfied.
- After the ignition switch is turned ON, two or more seconds passed.
- After the engine has started.
PROBABLE CAUSES
- Malfunction of the battery (battery life, insufficient charging,
loosened terminal)
- Malfunction of the laser radar power supply line (power supply line disconnection,
incorrect earthing, IG1 fuse fusing)
- Malfunction of the laser radar
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Refer to Battery test .
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Q.
Is the battery normal?
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Go to Step 2.
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Charge or replace the battery.
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STEP 2. Charging system check.
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Refer to GROUP 16 - Charging System.
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Q.
Is the charging system normal?
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Go to Step 3.
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Repair or replace the components related to the charging system.
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STEP 3. Resistance measurement at the laser radar connector (E terminal).
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(1)Disconnect the connector, and measure the resistance at the wiring harness.
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(2)Measure the resistance between the laser radar connector (E terminal) and body
earth. OK: Connect (2 Ω or lower)
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Q.
Is the check result normal?
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Go to Step 5.
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Go to Step 4.
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STEP 4. Disconnection check of the GND line between the laser radar
connector and body earth.
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Q.
Is the check result normal?
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent
Malfunction).
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Repair the connector(s) or wiring harness.
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STEP 5. Voltage measurement at the laser radar connector (IG terminal).
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(1)Disconnect the connector, and measure the resistance at the wiring harness.
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(2)Turn the ignition switch to the "ON" position.
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(3)Check the voltage between the laser radar connector (IG terminal) and body earth. OK: Battery voltage
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Q.
Is the check result normal?
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Go to Step 7.
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Go to Step 6.
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STEP 6. Check of short to earth and disconnection in the IG line between
the laser radar connector and ignition switch (IG1).
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Q.
Is the check result normal?
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Refer to the inspection procedure "Malfunction of the ignition switch power supply
system".
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Repair the connector(s) or wiring harness.
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STEP 7. Check whether the diagnosis code is set again.
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Check again if the diagnosis code is set in the laser radar.
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(1)Erase the set diagnosis code.
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(2)Turn the ignition switch to the "LOCK" (OFF) position.
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(4)Check if the diagnosis code is set.
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Q.
Is the diagnosis code set?
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Replace the laser radar (Refer to ).
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent
Malfunction).
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