What it means
Fuel pressure sensor B signal voltage below expected range. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Fuel pressure sensor B measures pressure at its assigned point in the fuel system and sends a signal to the engine control module. P018C sets when that signal falls below the circuit's expected electrical range, which can happen if the signal is shorted to ground or the connection has excessive resistance.
Common causes
Most likely first.
- Signal wire shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check engine light on
- Hard start, no start, or stalling under load
- Power loss especially at high load or rpm
- Possible long cranking time
How to diagnose it
- Check freeze-frame data and live sensor B pressure to see whether the low signal coincides with hard starting, load, or another operating condition.
- Identify sensor B's location from service information and inspect its connector and harness for chafing, moisture, corrosion, or pushed-back pins.
- Check sensor B's signal circuit for a short to ground and inspect the connector for high-resistance contact.
- Test the sensor's supply and ground, then check signal-circuit continuity against the manufacturer's specification.
- If the circuit checks out, test fuel pressure sensor B and compare its output with the manufacturer's specification before replacing it.
Common fixes
- Repair a signal wire rubbed through and shorted to ground.
- Clean or replace corroded or loose sensor B connector terminals.
- Restore a damaged supply or ground connection in the sensor circuit.
- Replace fuel pressure sensor B if its output remains too low with a sound circuit.
Can I keep driving?
Hard starting, stalling under load, and power loss can leave too little acceleration for safe traffic movement. Avoid high-load driving and stop if the engine stalls or cannot maintain power.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.