Code
P1207
DS
P — Powertrain
Fuel pressure regulation electrovalve short circuit to negative
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EN: 2
RU: 1
AI status
Completed
Completed
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Causes
- Damaged wiring insulation contacting chassis ground (chafed wire)
- Corroded or pushed‑out connector pins causing a short to ground
- Failed fuel pressure regulation electrovalve (internal short)
- Faulty ECU driver transistor or PCB short to ground
- Blown or incorrect fuse or poor ground connection
- Water ingress or contamination in connector harness
Symptoms
- MIL/Check Engine Light illuminated
- Engine may enter limp mode or reduced power
- Hard starting or no start in some conditions
- Poor drivability: hesitation, surging or reduced acceleration
- Possible abnormal fuel pressure (too high or uncontrolled)
- Occasional fuel system warning messages
What to check
- Read freeze frame and live data for fuel pressure and solenoid status
- Visually inspect wiring and connectors at the electrovalve and fuel rail
- Check connector pins for corrosion, bent pins or water
- Measure continuity from solenoid pin to chassis ground (looking for unintended low resistance)
- Measure solenoid coil resistance with connector disconnected
- Backprobe ECU output while commanding solenoid (observe voltage/PWM)
Signal parameters
- Typical solenoid coil resistance (model dependent): roughly 5–40 ohms (measure and compare to specification)
- Command signal: 0–12 V range; on many systems ECU uses PWM to regulate duty cycle (0–100%)
- When commanded off: line should not be hard shorted to ground — open circuit or battery voltage via pull‑up depending on driver type
- When commanded on: driver should provide expected voltage or PWM; a persistent ~0 V on the line with no command indicates short to ground
- PWM frequency often in the tens to a few hundred Hz (refer to factory data for exact value)
Diagnostic algorithm
- Retrieve DTCs and freeze frame data; record fuel rail pressure and any related codes.
- Perform visual inspection of harness from fuel pressure electrovalve to ECU: look for chafing, crush, repairs or water damage.
- With ignition off, disconnect the electrovalve connector. Measure coil resistance across the solenoid terminals and compare to specification. Infinite/open or very low (near 0 Ω) indicates fault.
- Check continuity between the solenoid negative/control pin and chassis ground. An unintended low resistance indicates a wiring short to ground.
- Inspect connector pins for corrosion, bent pins or shorted terminals. Repair or clean as required.
- With harness unplugged from ECU (or using backprobe if safe), command the solenoid on/off while monitoring the ECU output with a multimeter/oscilloscope. Verify the ECU is commanding and that the line is not being pulled to ground when it should be open.
- If wiring and connector are good but the fault remains, isolate the circuit and test by substituting a known good electrovalve (if available) or temporarily disconnect solenoid and observe code behavior.
- If measurements indicate the ECU driver is shorted to ground and wiring/solenoid are good, refer to manufacturer guidance for ECU repair/replacement.
- After repairs, clear codes and perform a road/functional test while monitoring fuel pressure and solenoid operation to confirm the fault is resolved.
Likely causes
- Wiring shorted to chassis at flex points or near fuel rail
- Connector terminal corrosion at the electrovalve or ECU
- Electrovalve coil internal short circuit
- ECU output stage failure (low-side driver stuck)
- Aftermarket work or repairs that disturbed wiring
Fault status
Status
Short to negative (short to ground) detected on fuel pressure regulation electrovalve circuit — circuit is being pulled to chassis negative.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
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