Code
P1190
MITSUBISHI
P — Powertrain
Fuel pressure sensor 2
Views:
UK: 8
EN: 12
RU: 17
AI status
Completed
Completed
100%
Causes
- Open or short in fuel pressure sensor 2 wiring
- Poor or corroded connector/pin contact at sensor or ECU
- Failed fuel pressure sensor 2 (internal fault)
- Lost or unstable reference voltage or ground to the sensor
- Contamination or mechanical failure in the fuel pressure sensor
- Actual fuel pressure out of expected range (pump/regulator/filter issue)
Symptoms
- Check Engine Light / MIL illuminated
- Stored freeze-frame data showing abnormal fuel pressure PID for sensor 2
- Hard start, extended cranking, or no-start conditions
- Poor idle, rough running, surging or stalling
- Reduced engine power or limp-home mode
- Poor fuel economy or rich/lean running indications
What to check
- Read and record DTC(s) and freeze-frame data with a capable scan tool
- Check for manufacturer TSBs or service notes related to P1190
- Visually inspect fuel pressure sensor 2 connector, wiring harness and ground for damage, corrosion or loose pins
- Confirm ECU connector condition where sensor harness terminates
- Monitor live fuel pressure sensor 2 PID and compare to sensor 1 (if present) with engine running and during key-on/engine-off
- Backprobe sensor connector to measure reference voltage, signal voltage and ground continuity
Signal parameters
- Typical sensor behavior: signal voltage increases with fuel pressure
- Expected sensor output range (typical, model-specific): approx. 0.5–4.5 V — consult vehicle service manual for exact values
- Reference supply: typically regulated 5 V reference from ECU (check for stable 5 V at sensor connector)
- Ground: solid chassis/ECU ground required; measure
- Compare sensor 2 PID to sensor 1 (if present) — they should track similarly under same conditions
Diagnostic algorithm
- Verify the P1190 code and any related fuel system or sensor codes. Record freeze-frame and live data of fuel pressure PIDs. 2) Visually inspect sensor 2 connector, wiring, and nearby harness for damage, corrosion, pin push-out, or water intrusion. Repair as needed. 3) With key ON (engine OFF) backprobe the sensor connector: verify stable reference voltage (≈5 V), signal voltage within expected key‑on range, and a good ground. 4) Start engine and monitor sensor 2 signal vs sensor 1 (if present) and vs actual fuel pressure measured with an independent fuel pressure gauge. Note discrepancies. 5) Perform a wiggle test on harness/connectors while watching live data for intermittent faults. 6) If signal is incorrect and wiring/connector/verifications are good, replace fuel pressure sensor 2 and retest. 7) If replacement does not clear the issue, inspect/repair ECU connector and grounds; consider ECU diagnostic/repair or follow factory troubleshooting for internal ECU input faults. 8) Clear codes and road test; confirm no return of P1190 and that fuel pressure behavior is normal.
Likely causes
- Damaged harness (chafing, rodent bite, pinched) to sensor 2
- Corroded or loose sensor connector or terminals
- Failed sensor due to age/contamination
- Fuel pump or pressure regulator failure causing abnormal pressure
- Intermittent ground or 5V reference from ECU
- Aftermarket work or recent service disturbed wiring/connectors
Fault status
Status
Fuel Pressure Sensor 2 circuit abnormal — check sensor, wiring/connectors, fuel pressure and ECU input.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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