Code
P1250
KIA
P — Powertrain
Pressure Regulator Control Solenoid Valve Open Or Short
Views:
UK: 27
EN: 35
RU: 25
AI status
Completed
Completed
100%
Causes
- Open circuit in solenoid harness
- Short to ground or short to battery in solenoid circuit
- Faulty pressure regulator control solenoid valve
- Corroded or loose connector/pins
- Blown fuse or fusible link supplying the solenoid circuit
- Faulty PCM/ECM or internal driver failure
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Reduced engine power or limp-home mode
- Hesitation or poor throttle response
- Rough idle or stalling
- Decreased fuel economy
- Possible hard starting or black exhaust smoke (if fuel pressure affected)
What to check
- Read freeze frame and live data with a diagnostic scanner to confirm conditions when the code set
- Visual inspection of solenoid, connector, wiring harness, and nearby components for damage, corrosion, or oil/water contamination
- Check related fuses and fusible links for continuity
- Backprobe the solenoid connector with key ON (engine OFF) to measure supply voltage and control signal
- Measure solenoid coil resistance with battery disconnected
- Check continuity from solenoid pins to the PCM connector and to ground
Signal parameters
- Supply voltage: ~12 V (key ON) present at solenoid power feed (if applicable)
- Control signal: PWM from PCM; frequency commonly 50–300 Hz (varies by application)
- Duty cycle: 0–100% depending on commanded pressure
- Solenoid coil resistance: typically tens of ohms (example 10–100 Ω) — compare to spec
- Short to ground: near 0 Ω between control wire and chassis ground
- Short to battery: near 0 Ω between control wire and battery positive
Diagnostic algorithm
- Retrieve and record all freeze frame, readiness, and live data. Note conditions when code set (RPM, throttle, load).
- Perform a thorough visual inspection of the solenoid, harness, and connector. Repair visible damage and reseal/replace corroded connectors.
- Verify fuse(s) and power feed to the solenoid circuit for continuity. Replace blown fuses and investigate cause if recurrent.
- With ignition OFF, disconnect solenoid connector and measure coil resistance across solenoid pins. Compare to manufacturer specification; an open or very low reading indicates a failed solenoid.
- With key ON (engine OFF) backprobe the connector to check that battery voltage is present on the power feed (if applicable) and that the PCM control pin shows a signal when commanded by a scan tool.
- Use a scan tool to command the solenoid ON/OFF while observing control signal (voltage or waveform). If commanded but no response and wiring is good, suspect solenoid or internal PCM driver.
- Check continuity and resistance of the control wire from the solenoid connector to the PCM pin. Repair any opens or shorts (to ground or battery).
- If wiring and solenoid test good but code persists, scope the PCM output to confirm proper PWM frequency and duty cycle. Replace PCM only after wiring and component failure ruled out.
- After repairs, clear codes and perform a road test to confirm the code does not return and that drivability is restored.
Likely causes
- Broken wire or connector between ECM and solenoid
- Solenoid coil failed (open or shorted)
- Connector corrosion or water intrusion at solenoid
- Shorted circuit due to chafing against chassis
- Faulty PCM output stage (less common)
Fault status
Status
Pressure regulator control solenoid valve circuit open or short detected. ECM cannot properly control regulator; MIL set. Check wiring, connector, solenoid, and PCM output.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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