Left Front Center Sensor Circuit Failure
The left front center sensor (typically a suspension or stability control sensor) is sending bad data or no signal to the ECU, like a broken speedometer needle that won't move. The vehicle's safety and handling systems can't trust this sensor's input anymore.
The ECU monitors the left front wheel speed or suspension position sensor voltage and signal continuity. It compares the signal against expected ranges and checks for open circuits, shorts, or out-of-range voltage. If the signal is absent, erratic, or beyond threshold for more than a calibrated duration, the fault is triggered.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Sensor voltage | 0.5–4.5 V (varies by sensor type) | <0.1 V or >4.9 V; no signal |
| Signal plausibility | Matches right-side sensor pattern | Diverges >threshold or remains static |
Code C1718 is classified as a serious fault. If your check engine light is flashing — not just steady — pull over safely and do not continue driving. A flashing CEL indicates an active misfire or critical failure that can cause catalytic converter damage within minutes or permanent engine harm within miles. Contact a certified mechanic immediately. Do not attempt roadside repairs on high-severity codes unless you are trained to do so.
Once the fault is repaired, C1718 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.