P2D90

Code

Generic P — Powertrain

Engine Oil Pressure Sensor/Switch C Circuit High

Brand: Generic

Type: P — Powertrain

Views: UK: 27 EN: 44 RU: 24

AI status

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Page language: EN

Causes

Short to battery positive (VB) on the sensor signal wire
Faulty oil pressure sensor or switch (C)
Open or damaged wiring harness or connector (intermittent or short)
Corroded or pushed-back terminal in connector
Poor or missing sensor ground
PCM input circuit fault or internal failure

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Stored P2D90 code and possible freeze-frame data
Oil pressure gauge or dash lamp may show erratic, unusually high, or normal readings (depending on circuit type)
Possible drivability unaffected (engine usually runs normally)
Intermittent MIL if wiring is intermittent

What to check

Retrieve freeze-frame and live data with a scan tool; monitor oil pressure sensor/switch C signal
Visually inspect sensor, connector, and wiring for damage, corrosion, or loose pins
Backprobe the sensor connector to measure reference voltage and signal with key on and engine running (as required)
Check for continuity to PCM and for shorts to battery positive using a DMM
Compare reading to another identical sensor input (if available) or swap with a known-good sensor when applicable
Check PCM ground and related ground points

Signal parameters

Reference voltage typically ≈ 5.0 V (varies by vehicle) supplied to the sensor
Normal sensor signal range typically 0.0–4.5 V depending on oil pressure; a 'high' fault often means signal > ~4.5 V or pulled to VB
If switch type, correct idle signal may be ~VB when open; PCM expects a ground switch closure — a hard VB at the input can register as 'high'
Typical circuit current low (sensor draws small mA); absence of expected ground or short to VB will alter values
Values and thresholds vary by manufacturer — consult specific vehicle service data

Diagnostic algorithm

Verify the code using a scan tool. Note freeze-frame and live data for oil pressure sensor/switch C. Clear codes and attempt to reproduce.
Perform a visual inspection of the sensor, harness, and connector for damage, corrosion, melted insulation, or evidence of shorting.
With key ON (engine OFF) backprobe the sensor connector: confirm reference voltage (usually ~5V) and check the signal pin voltage. A signal significantly above expected (≈4.5V or equal to battery voltage) indicates a short/high condition.
Check continuity from the sensor signal pin to the PCM input pin. With the harness disconnected, measure resistance to the PCM; an open or very high resistance indicates an open circuit.
Check for short to battery: disconnect the sensor and measure voltage on the harness signal wire to ground. If voltage is present with the sensor disconnected, trace for a short to VB or an aftermarket device tied into the circuit.
Check ground(s) associated with the sensor and PCM. Repair any poor grounds.
If wiring and connectors test good, substitute a known-good oil pressure sensor/switch or install a new OEM sensor and re-test.
If fault persists after sensor replacement and wiring checks, test/replace PCM or consult manufacturer technical service for module testing.
If required, confirm actual oil pressure mechanically with a mechanical gauge to rule out a genuine oil pressure condition affecting sensor behavior.
After repairs, clear codes and perform road test/drive cycles to confirm the fault does not return.

Likely causes

Damaged wiring or connector causing short/high voltage on the signal
Failed oil pressure sensor/switch producing a high or stuck signal
Connector corrosion or bent terminals
Short to ignition/battery feed on the signal lead

Fault status

⚠️ Status

Engine Oil Pressure Sensor/Switch C Circuit High — signal voltage on oil pressure sensor C circuit is above expected range. Possible causes: short to battery, faulty sensor, wiring/connector fault, or PCM input problem.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours