Code
P0192
MITSUBISHI
P — Powertrain
Fuel pressure sensor low input
Views:
UK: 34
EN: 52
RU: 63
AI status
Completed
Completed
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Causes
- Faulty fuel rail pressure sensor (internal failure)
- Signal wire shorted to ground
- Open or corroded connector / poor terminal contact
- Lost or low 5V reference from the ECM or poor sensor ground
- Low actual fuel pressure (weak fuel pump, clogged filter, failed regulator)
- ECM fault (rare)
Symptoms
- MIL/Check Engine lamp on
- Hard starting or extended cranking
- Poor acceleration, hesitation or limp-mode operation
- Engine may stall or run roughly
- Fuel trim anomalies / abnormal scan data for rail pressure
What to check
- Read stored codes and freeze frame data with a scan tool; note engine conditions when fault set
- Inspect sensor connector and wiring for damage, corrosion, or pin push-out
- Backprobe sensor harness: verify 5V reference present, good ground, and signal voltage level
- Wiggle test wiring/connectors while monitoring live data for intermittent changes
- Measure actual fuel rail pressure with a mechanical gauge to confirm true pressure
- Check related fuses/relays and battery voltage during testing
Signal parameters
- Typical sensor type: 3-wire (5V reference, ground, signal) — confirm with vehicle wiring diagram
- Expected reference voltage: approx. 5.0 V (±0.2 V)
- Expected signal range: roughly 0.5 V (low pressure) to ~4.5 V (high pressure) — varies by sensor
- Fault threshold: signal significantly below expected low-end (commonly < ~0.2–0.5 V) or outside manufacturer spec
- Ground circuit: near 0 V with low resistance to chassis ground
Diagnostic algorithm
- Confirm P0192 present and check for additional codes (P0190/P0191/P0193 or fuel system codes).
- Record live data: fuel rail pressure sensor voltage and fuel rail pressure reading. Note if sensor shows near-zero voltage or unrealistically low pressure.
- Visually inspect harness and connector for damage, corrosion, water intrusion, or loose pins.
- Backprobe connector with key on (engine off): verify 5V reference at reference pin, verify ground continuity to chassis, and measure signal pin voltage.
- If reference or ground missing, trace and repair wiring / fuses / ECM connector. If signal is low while reference and ground are good, suspect sensor or actual low mechanical pressure.
- Confirm actual fuel pressure with a certified fuel pressure gauge at the rail. Compare gauge reading to vehicle spec.
- If mechanical pressure is normal but sensor signal remains low, disconnect sensor and measure sensor output or resistance per service manual; replace sensor if out of spec.
- If replacing sensor does not clear code and wiring checks good, perform continuity and short-to-ground tests on signal wire back to ECM; if wiring is good, consider ECM input fault and consult OEM guidance.
- Clear codes and perform road test to verify repair; recheck for recurrence and monitor live data.
Likely causes
- Damaged or shorted signal wiring to ground
- Failed sensor
- Poor connector pins/corrosion or loose terminal
- Low fuel system pressure (pump/filter/regulator)
- Faulty ECM (least likely)
Fault status
Status
P0192 — Fuel pressure sensor circuit low input. Check sensor, wiring/connectors, reference 5V and ground, and verify actual fuel rail pressure.
Repair difficulty: Medium
Diagnostic time: 0.5–2 hours
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