U3518
High Voltage System Interlock Circuit C High
U3518 is an OBD-II diagnostic trouble code meaning: High Voltage System Interlock Circuit C High. Common causes: open circuit in high voltage blocking circuit, damaged or oxidized contacts in connectors. Estimated repair cost: $17–111.
Symptoms
- Check Engine light comes on
- The car may go into emergency mode
- Reduced power or inability to start
- Warning messages appear on the dashboard
Causes
- Open circuit in high voltage blocking circuit
- Damaged or oxidized contacts in connectors
- High Voltage Lockout Sensor Malfunction
- Wiring harness damage
- Problems with the high voltage system control unit
How to Fix
- Conduct a visual inspection of high-voltage connectors and harnesses
- Check the integrity of the interlock circuit using a multimeter
- Clean connector contacts from oxidation
- Replace damaged circuit components
- Repair only from an authorized dealer
Related codes
Error U3518 by Vehicle Brand
FAQ
What does the U3518 code mean?
U3518 is an OBD-II diagnostic trouble code that indicates: High Voltage System Interlock Circuit C High
What causes a U3518 error code?
The most common causes of U3518 include: Open circuit in high voltage blocking circuit; Damaged or oxidized contacts in connectors; High Voltage Lockout Sensor Malfunction; Wiring harness damage.
How do I fix a U3518 diagnostic trouble code?
To fix U3518: Conduct a visual inspection of high-voltage connectors and harnesses. Check the integrity of the interlock circuit using a multimeter. Clean connector contacts from oxidation. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with U3518?
Do not drive — repair immediately
How much does it cost to fix U3518?
The estimated repair cost for U3518 is $17–111. Actual cost depends on your vehicle, location, and labor rates.
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