Ignition Cylinder Sensor Ground Short
The ignition cylinder sensor's ground wire has a short circuit, meaning electricity is leaking where it shouldn't be. Think of it like water escaping through a hole in a pipe instead of flowing to where it needs to go.
The ECU monitors the ground return signal from the ignition cylinder sensor for proper voltage levels and circuit continuity. When a ground short exists, the sensor signal voltage drops below expected thresholds or shows abnormal resistance patterns. The ECU detects this fault condition and triggers the code.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Ground Signal Voltage | 0.1-0.5V (stable ground reference) | Below 0V or erratic fluctuation indicating short |
| Circuit Resistance | Less than 5 ohms to ground | Greater than 10 ohms or unstable resistance |
Code B1494 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.
Once the fault is repaired, B1494 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.