P055D

Code

Generic P — Powertrain

Engine Oil Pressure Sensor/Switch B High

Brand: Generic

Type: P — Powertrain

Views: UK: 22 EN: 35 RU: 25

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Open or shorted wiring in the oil pressure sensor B circuit (including connector pins)
Short to battery voltage on the sensor signal circuit
Poor or corroded connector or ground at the sensor
Failed oil pressure sensor/switch (internal fault)
Mechanical oil system issue causing abnormally high pressure (rare)
Faulty PCM or intermittent PCM input circuit

Symptoms

Oil pressure warning lamp or message
Malfunction Indicator Lamp (MIL) may be set
Possible limp-home behavior on some vehicles
Noisy lifters or engine if oil pressure is actually abnormal (rare with this code)
Intermittent warning or lamp illumination depending on wiring fault

What to check

Retrieve freeze-frame and live data for oil pressure sensor B if available
Visually inspect sensor connector and wiring for damage, corrosion, or pin push-out
Check for proper connector seating and terminal tension
Backprobe the sensor signal and reference circuits with ignition ON (engine off) and during cranking/idle
Measure sensor circuit voltage at the PCM connector and at the sensor
Perform a mechanical oil pressure gauge test to confirm actual oil pressure

Signal parameters

Typical reference (excitation) voltage to sensor: approx. 5 V (varies by manufacturer)
Typical sensor output range: ~0.5 V (low pressure) to ~4.5 V (high pressure); fault often >4.5 V or near battery voltage
If the sensor is a switch type, expected states are near 0 V (closed to ground) or pulled to reference/B+ when open; consult vehicle data
Short to battery will show near battery voltage (~12 V) at the sensor signal terminal with ignition ON
Open circuit will often show high (pulled up) or no valid signal to the PCM depending on design

Diagnostic algorithm

Verify code and record freeze-frame/live-data values for oil pressure sensor B and related channels.
Visually inspect sensor, harness, and connector for damage, corrosion or loose pins. Repair any obvious damage.
With ignition ON (engine off) backprobe the sensor signal, reference, and ground pins at the sensor: verify reference voltage (≈5 V) and good ground.
Measure signal voltage at the sensor while comparing to the PCM signal pin to identify wiring open or short (voltage should match at both ends).
Wiggle test harness with engine running or during data capture to check for intermittent faults and watch live-data for jumps to high voltage.
If wiring checks good but signal remains high, disconnect the sensor and measure resistance/voltage at the harness to detect short to battery or open circuit per vehicle service data.
Install a known-good sensor (if available) or bench-test the sensor per manufacturer resistance/voltage specifications.
Verify actual oil pressure with a mechanical gauge to rule out a genuine hydraulic overpressure condition.
If sensor, harness and oil pressure are good, inspect PCM connector and grounds; consider PCM input circuit testing or replacement per OEM procedures.
After repairs, clear codes and confirm vehicle operates normally and code does not return under road/test conditions.

Likely causes

Damaged wiring or connector (open/high resistance or short to B+) at sensor
Failed oil pressure sensor/switch B
Corroded/loose ground or power reference to sensor
Less likely: actual high engine oil pressure or PCM fault

Fault status

⚠️ Status

Engine Oil Pressure Sensor/Switch B Circuit High — PCM detected a higher-than-expected signal from the oil pressure sensor/switch B (possible open, short to battery, failed sensor, or abnormal oil pressure).

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.5 hours