Open or high-resistance connection in the sensor signal circuit, including a broken wire or corroded terminal; Short to voltage on the signal circuit, often from chafed insulation against a power wire; Failed fuel pressure sensor B, typically an internal open circuit or reference voltage fault; Poor ground connection at the sensor or chassis, causing a floating reference; Faulty powertrain control module driver or internal pull-up resistor (rare but possible); Contaminated or incorrect fuel pressure sensor installation causing mechanical binding

DTC codes / P01xx · Fuel and air metering / P018D

P018DFuel Pressure Sensor B Circuit High

Q: What does code P018D mean?

Fuel Pressure Sensor B Circuit High. P018D indicates that the powertrain control module has detected an abnormally high voltage on the signal circuit of fuel pressure sensor B, which is typically a sensor monitoring the low-pressure side of the fuel system. The computer expects the sensor's output to stay within a calibrated voltage range, and a sustained high reading tells it the circuit is open, shorted to voltage, or the sensor itself has failed.

P018D indicates that the powertrain control module has detected an abnormally high voltage on the signal circuit of fuel pressure sensor B, which is typically a sensor monitoring the low-pressure side of the fuel system. The computer expects the sensor's output to stay within a calibrated voltage range, and a sustained high reading tells it the circuit is open, shorted to voltage, or the sensor itself has failed.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Reduced engine performance or a sudden limp-home mode under load
Difficulty starting or a crank-no-start condition in some cases
Poor fuel economy or rich-running exhaust smell
Intermittent hesitation or stumble during acceleration
A fuel pressure-related message displayed on the driver information center

Common causes, most likely first

Open or high-resistance connection in the sensor signal circuit, including a broken wire or corroded terminal
Short to voltage on the signal circuit, often from chafed insulation against a power wire
Failed fuel pressure sensor B, typically an internal open circuit or reference voltage fault
Poor ground connection at the sensor or chassis, causing a floating reference
Faulty powertrain control module driver or internal pull-up resistor (rare but possible)
Contaminated or incorrect fuel pressure sensor installation causing mechanical binding

How to diagnose and fix it

Connect a scan tool and record live fuel pressure sensor B voltage and any freeze-frame data to confirm the high signal
Visually inspect the sensor connector, wiring harness, and ground points for corrosion, chafing, or loose pins
Perform a voltage drop test on the sensor ground circuit and check reference voltage at the connector
Back-probe the signal wire and compare sensor output against a mechanical fuel pressure gauge to isolate sensor versus circuit
Disconnect the sensor and check for a short to voltage on the signal wire with the key on and engine off
Replace the fuel pressure sensor B if the circuit tests good but the signal remains stuck high
Clear the diagnostic trouble code and verify the repair with a road test and live data review

What a high fuel pressure signal really means

A high signal voltage does not always mean the sensor is bad; an open signal wire will pull the PCM's internal pull-up voltage to the top of its range and set this code.
Technicians often overlook a shared five-volt reference circuit that feeds multiple sensors, so a short in another sensor can drag the fuel pressure signal high.
On some vehicles, fuel pressure sensor B monitors low-pressure side pressure, and a failing in-tank lift pump can cause erratic readings that mimic a circuit fault.
A corroded ground strap between the engine and chassis can elevate sensor return voltage and trigger P018D without any fault in the sensor wiring itself.
Replacing the sensor without checking the connector terminal tension frequently leads to a repeat code because spread pins create an intermittent high signal.

Can I keep driving with P018D?

The vehicle may enter limp-home mode or run rich, so avoid heavy acceleration and long trips until the fault is diagnosed. If the engine starts and runs smoothly, a short drive to a repair shop is acceptable, but stop driving immediately if you notice fuel smell, rough running, or stalling.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.