P01C6

Code

Generic P — Powertrain

Fuel Pressure Sensor A Circuit High

Brand: Generic

Type: P — Powertrain

Views: UK: 24 EN: 120 RU: 28

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Page language: EN

Causes

Shorted signal wire to battery/ignition voltage (B+)
Faulty fuel rail pressure sensor (sensor A)
Poor or open ground or reference supply to the sensor
Corroded/damaged connector or wiring harness
PCM/ECM input circuit fault

Symptoms

Malfunction Indicator Lamp (MIL) on
Engine may run poorly, stall, hesitate, or have reduced power
Hard start or extended cranking time
Poor fuel economy or surging
Possible limp-home mode depending on vehicle

What to check

Read stored codes and freeze frame data; check for related codes (fuel pump, fuel pressure, MAP/boost)
Scan live fuel rail pressure and sensor voltage while key on and during cranking/idle
Perform visual inspection of sensor, connector, and wiring for damage or corrosion
Backprobe sensor connector to measure reference voltage, signal voltage and ground
Wiggle harness while monitoring signal to look for intermittent faults
Measure continuity/resistance between sensor signal and ECM pin, and between sensor ground and chassis ground

Signal parameters

Sensor signal typical range: ~0.5 V (low/near 0 pressure) to ~4.5 V (high/full-scale) — actual range depends on vehicle
Reference supply: nominal 5.0 V reference (approx.) from ECM
Sensor ground: near 0 V (secure chassis/ECM ground)
At key-on engine-off the signal is often at the low end of the range (varies by rail pressure)

Diagnostic algorithm

Record freeze frame and all stored DTCs. Note engine conditions when code set (RPM, temp, fuel rail pressure).
Visual inspection: check the fuel pressure sensor connector for bent pins, corrosion, water intrusion, or damage to the harness; repair as needed.
With a DVOM or oscilloscope and scan tool ready, backprobe the sensor harness. With key ON (engine off) verify the ECM reference voltage (~5 V) at the reference pin and a good ground at the ground pin.
Measure the sensor signal voltage with key ON and with engine running. Confirm if the signal is above the expected range or stuck at near-B+ (indicates short to B+).
If signal is high, disconnect the sensor harness and measure the signal wire continuity to the ECM. Check for short to battery by measuring voltage between the signal wire and ground with the sensor disconnected.
Wiggle test the wiring and connector while monitoring signal voltage and scan data to find intermittent faults.
If wiring and connectors are good and reference/ground are correct but signal remains high with a known-good replacement sensor, suspect ECM input circuit fault — verify with manufacturer procedures before replacing ECM.
After repair or replacement, clear codes and test drive to confirm the code does not return and fuel rail pressure behavior is normal.

Likely causes

Damaged wiring or connector causing short to B+ on the sensor signal
Failed fuel rail pressure sensor producing out-of-range output
Bad sensor ground or missing reference voltage (5 V)
Intermittent connector contact or corrosion
Less likely: PCM input driver fault

Fault status

⚠️ Status

Fuel Pressure Sensor A Circuit High — sensor output voltage above expected range. Possible short to battery, sensor failure, wiring/connector fault, or ECM input issue.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.5 hours