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Home / DTC / P0090 — Fuel Pressure Regulator A Control Circuit/Open

P0090 — Fuel Pressure Regulator A Control Circuit/Open

Detailed page for trouble code P0090.

34,099codes
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11,608generic
22,491specific
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Code

P0090

Generic P — Powertrain

Fuel Pressure Regulator A Control Circuit/Open

Brand: Generic
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or broken wiring in the fuel pressure regulator control circuit
  • Disconnected, corroded, or damaged connector at the regulator/solenoid
  • Failed fuel pressure regulator or control solenoid (open coil)
  • Blown fuse or faulty power/ground supply to the regulator circuit
  • Poor ground or high-resistance ground connection
  • ECM output driver fault

Symptoms

  • Check Engine Light (MIL) illuminated
  • Hard start or no start conditions
  • Rough idle, hesitation or poor acceleration
  • Reduced engine power or limp-in mode
  • Decreased fuel economy or lean/rich running
  • Stored fuel system related freeze-frame data (low or uncontrolled fuel rail pressure)

What to check

  • Read freeze frame and live data for fuel rail pressure and regulator command
  • Visual inspection of regulator connector, wiring harness, and chassis ground
  • Check relevant fuse/relay for the fuel pump/regulator circuit
  • Measure resistance of regulator/solenoid coil (unplugged) with multimeter
  • Check for battery voltage at the regulator power pin with ignition ON
  • Check continuity from regulator control pin to ECM pin

Signal parameters

  • Typical coil resistance (solenoid) — often 1–40 ohms depending on vehicle; open = infinite/OL
  • Supply/Key‑ON voltage to regulator power pin — ~11–14.5 V (vehicle battery voltage range)
  • Control signal from ECM — usually a PWM ground/low-side switch; duty cycle 0–100%
  • PWM frequency commonly in the tens to a few hundred Hz (vehicle dependent)
  • Ground/return continuity — low resistance (

Diagnostic algorithm

  1. Retrieve freeze frame and live data. Note fuel rail pressure, regulator command, and engine conditions when code set.
  2. Perform a visual inspection of the regulator, connector, and wiring for damage, corrosion, or disconnection.
  3. With ignition OFF, disconnect the regulator connector and measure the coil resistance. Infinite/OL indicates an open coil — replace regulator.
  4. With connector unplugged and ignition ON (engine OFF), check for battery power on the regulator power pin and good ground on the ground pin. Replace blown fuses or repair power/ground as needed.
  5. Check continuity between the regulator control pin and the ECM control pin. Repair any open or high-resistance wiring.
  6. If power and wiring are good, check the ECM control output with a lab scope or duty-cycle capable meter while cranking/running to verify PWM signal presence and behavior. Do not probe connectors that could short circuits — follow vehicle-specific safe test points.
  7. Compare commanded fuel pressure to actual fuel rail pressure with a fuel pressure gauge while exercising the regulator command (if safe to do so). Observe whether pressure responds to ECM commands.
  8. If wiring and regulator test good but no proper ECM output, consider ECM fault. Confirm with manufacturer diagnostics before replacement.
  9. After repairs, clear codes and perform a test drive to verify the fault does not return and pressures/driveability are normal.

Likely causes

  • Faulty fuel pressure regulator / control solenoid (open coil)
  • Damaged/disconnected harness or connector at the regulator
  • Blown fuse or loss of power/ground to the regulator
  • High resistance in wiring (pinched/chafed) between ECM and regulator

Fault status

⚠️ Status
Open or high-resistance detected in Fuel Pressure Regulator A control circuit. ECM unable to command regulator; fuel rail pressure control may be lost and limp strategy may be used.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.5 hours

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Code

P0090

LAND ROVER P — Powertrain

Fuel pressure regulator control circuit

Brand: LAND ROVER
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or broken wiring in the fuel pressure regulator control circuit
  • Disconnected, corroded, or damaged connector at the regulator/solenoid
  • Failed fuel pressure regulator or control solenoid (open coil)
  • Blown fuse or faulty power/ground supply to the regulator circuit
  • Poor ground or high-resistance ground connection
  • ECM output driver fault

Symptoms

  • Check Engine Light (MIL) illuminated
  • Hard start or no start conditions
  • Rough idle, hesitation or poor acceleration
  • Reduced engine power or limp-in mode
  • Decreased fuel economy or lean/rich running
  • Stored fuel system related freeze-frame data (low or uncontrolled fuel rail pressure)

What to check

  • Read freeze frame and live data for fuel rail pressure and regulator command
  • Visual inspection of regulator connector, wiring harness, and chassis ground
  • Check relevant fuse/relay for the fuel pump/regulator circuit
  • Measure resistance of regulator/solenoid coil (unplugged) with multimeter
  • Check for battery voltage at the regulator power pin with ignition ON
  • Check continuity from regulator control pin to ECM pin

Signal parameters

  • Typical coil resistance (solenoid) — often 1–40 ohms depending on vehicle; open = infinite/OL
  • Supply/Key‑ON voltage to regulator power pin — ~11–14.5 V (vehicle battery voltage range)
  • Control signal from ECM — usually a PWM ground/low-side switch; duty cycle 0–100%
  • PWM frequency commonly in the tens to a few hundred Hz (vehicle dependent)
  • Ground/return continuity — low resistance (

Diagnostic algorithm

  1. Retrieve freeze frame and live data. Note fuel rail pressure, regulator command, and engine conditions when code set.
  2. Perform a visual inspection of the regulator, connector, and wiring for damage, corrosion, or disconnection.
  3. With ignition OFF, disconnect the regulator connector and measure the coil resistance. Infinite/OL indicates an open coil — replace regulator.
  4. With connector unplugged and ignition ON (engine OFF), check for battery power on the regulator power pin and good ground on the ground pin. Replace blown fuses or repair power/ground as needed.
  5. Check continuity between the regulator control pin and the ECM control pin. Repair any open or high-resistance wiring.
  6. If power and wiring are good, check the ECM control output with a lab scope or duty-cycle capable meter while cranking/running to verify PWM signal presence and behavior. Do not probe connectors that could short circuits — follow vehicle-specific safe test points.
  7. Compare commanded fuel pressure to actual fuel rail pressure with a fuel pressure gauge while exercising the regulator command (if safe to do so). Observe whether pressure responds to ECM commands.
  8. If wiring and regulator test good but no proper ECM output, consider ECM fault. Confirm with manufacturer diagnostics before replacement.
  9. After repairs, clear codes and perform a test drive to verify the fault does not return and pressures/driveability are normal.

Likely causes

  • Faulty fuel pressure regulator / control solenoid (open coil)
  • Damaged/disconnected harness or connector at the regulator
  • Blown fuse or loss of power/ground to the regulator
  • High resistance in wiring (pinched/chafed) between ECM and regulator

Fault status

⚠️ Status
Open or high-resistance detected in Fuel Pressure Regulator A control circuit. ECM unable to command regulator; fuel rail pressure control may be lost and limp strategy may be used.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.5 hours

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P0091 P0092 P0093 P0087 P0088 P0190
320

Browse 320 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

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Code

P0090

MITSUBISHI P — Powertrain

Fuel pressure up solenoid

Brand: MITSUBISHI
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or broken wiring in the fuel pressure regulator control circuit
  • Disconnected, corroded, or damaged connector at the regulator/solenoid
  • Failed fuel pressure regulator or control solenoid (open coil)
  • Blown fuse or faulty power/ground supply to the regulator circuit
  • Poor ground or high-resistance ground connection
  • ECM output driver fault

Symptoms

  • Check Engine Light (MIL) illuminated
  • Hard start or no start conditions
  • Rough idle, hesitation or poor acceleration
  • Reduced engine power or limp-in mode
  • Decreased fuel economy or lean/rich running
  • Stored fuel system related freeze-frame data (low or uncontrolled fuel rail pressure)

What to check

  • Read freeze frame and live data for fuel rail pressure and regulator command
  • Visual inspection of regulator connector, wiring harness, and chassis ground
  • Check relevant fuse/relay for the fuel pump/regulator circuit
  • Measure resistance of regulator/solenoid coil (unplugged) with multimeter
  • Check for battery voltage at the regulator power pin with ignition ON
  • Check continuity from regulator control pin to ECM pin

Signal parameters

  • Typical coil resistance (solenoid) — often 1–40 ohms depending on vehicle; open = infinite/OL
  • Supply/Key‑ON voltage to regulator power pin — ~11–14.5 V (vehicle battery voltage range)
  • Control signal from ECM — usually a PWM ground/low-side switch; duty cycle 0–100%
  • PWM frequency commonly in the tens to a few hundred Hz (vehicle dependent)
  • Ground/return continuity — low resistance (

Diagnostic algorithm

  1. Retrieve freeze frame and live data. Note fuel rail pressure, regulator command, and engine conditions when code set.
  2. Perform a visual inspection of the regulator, connector, and wiring for damage, corrosion, or disconnection.
  3. With ignition OFF, disconnect the regulator connector and measure the coil resistance. Infinite/OL indicates an open coil — replace regulator.
  4. With connector unplugged and ignition ON (engine OFF), check for battery power on the regulator power pin and good ground on the ground pin. Replace blown fuses or repair power/ground as needed.
  5. Check continuity between the regulator control pin and the ECM control pin. Repair any open or high-resistance wiring.
  6. If power and wiring are good, check the ECM control output with a lab scope or duty-cycle capable meter while cranking/running to verify PWM signal presence and behavior. Do not probe connectors that could short circuits — follow vehicle-specific safe test points.
  7. Compare commanded fuel pressure to actual fuel rail pressure with a fuel pressure gauge while exercising the regulator command (if safe to do so). Observe whether pressure responds to ECM commands.
  8. If wiring and regulator test good but no proper ECM output, consider ECM fault. Confirm with manufacturer diagnostics before replacement.
  9. After repairs, clear codes and perform a test drive to verify the fault does not return and pressures/driveability are normal.

Likely causes

  • Faulty fuel pressure regulator / control solenoid (open coil)
  • Damaged/disconnected harness or connector at the regulator
  • Blown fuse or loss of power/ground to the regulator
  • High resistance in wiring (pinched/chafed) between ECM and regulator

Fault status

⚠️ Status
Open or high-resistance detected in Fuel Pressure Regulator A control circuit. ECM unable to command regulator; fuel rail pressure control may be lost and limp strategy may be used.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.5 hours

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P0091 P0092 P0093 P0087 P0088 P0190
406

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+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
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