Code
P1144
SUBARU
P — Powertrain
Pressure Sensor Circuit High Input
Views:
UK: 30
EN: 52
RU: 34
AI status
Completed
Completed
100%
Causes
- Short to battery on the pressure sensor signal wire
- Failed/shorted pressure sensor (fuel rail, MAP/boost or other pressure sensor)
- Poor or missing sensor ground
- Corroded/loose connector or pin damage
- Open/short in harness between sensor and PCM
- Incorrect reference voltage from PCM (internal PCM fault)
Symptoms
- Check Engine Light (MIL) illuminated
- High or erratic pressure reading in live data
- Hard starting, rough idle or loss of power (if fuel/boost pressure impacted)
- Abnormal fuel trims or drivability issues
- Stored freeze frame data showing elevated pressure sensor voltage
What to check
- Scan for P1144 and related codes; record freeze-frame and live data for the pressure sensor and fuel/boost pressure
- Visual inspection of sensor, connector and wiring for corrosion, damage, pushed-out pins or melted insulation
- Backprobe sensor connector with ignition ON to verify reference voltage, signal voltage and ground presence
- Wiggle harness and connector while monitoring live data to check for intermittent faults
- Measure continuity and resistance between sensor ground and vehicle chassis ground and between sensor signal and PCM pin (engine off)
- Inspect actual system pressure (fuel rail or boost) with a mechanical gauge where applicable to rule out true overpressure
Signal parameters
- Reference (supply) voltage: ~5.0 V (key ON) for most pressure sensors — verify with meter
- Expected signal range: ~0.5–4.5 V depending on sensor and pressure; consult vehicle-specific data
- High input threshold: signal near battery voltage or >4.5–4.8 V typically sets a high-input DTC
- Ground continuity: chassis ground
- Signal circuit resistance to PCM: low continuity (typically
Diagnostic algorithm
- Retrieve freeze-frame and live data; note sensor voltage and related parameters (fuel pressure, MAP, fuel trims).
- Perform a careful visual inspection of the sensor, connector and harness for heat damage, corrosion, pin push-out or exposed conductors.
- With ignition ON (engine off), backprobe the sensor connector: verify reference voltage (~5 V), sensor signal voltage (should be within expected range and not at battery voltage), and a good ground. If reference voltage missing, suspect PCM or harness.
- If signal is high with the sensor disconnected: check for short to battery on the signal wire. Disconnect the connector and measure voltage at the harness side. If high, trace and repair short to 12 V.
- If reference voltage present but signal high only when sensor connected: suspect a failed sensor — swap with a known-good sensor or substitute an equivalent to verify.
- Check continuity and resistance between sensor signal pin and PCM input pin (with ignition OFF). Repair any opens or high resistance. Also check sensor ground continuity to chassis ground.
- If wiring and sensor test good and no short present, test PCM output (reference) and input circuits per factory procedures. Replace PCM only after confirming sensor and harness are good.
- Clear codes and road test to confirm repair. If code returns, continue tracing per factory wiring diagrams.
- Always observe safety: relieve fuel pressure before disconnecting fuel-system components; take precautions when testing high boost or fuel pressures.
Likely causes
- Damaged or corroded sensor connector/wiring causing a short to battery
- Failed pressure sensor with high output
- Poor sensor ground or missing reference voltage from PCM
- Wiring shorted to constant 12 V supply
- Less likely: PCM internal fault
Fault status
Status
P1144 — Pressure Sensor Circuit High Input: PCM detected signal voltage higher than expected from the pressure sensor. Inspect sensor, wiring, and power/ground circuits.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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