Open or shorted wiring or connectors in the fuel pressure regulator control circuit (both sources). Defective fuel pressure regulator (both sources). Faulty fuel rail pressure sensor (OBD-Codes.com). Engine computer (PCM) failure or a PCM programming error (both sources).

Repair broken, chewed, shorted or corroded wiring and connectors in the regulator circuit. Replace the electronic fuel pressure regulator if it does not respond to control voltage after the circuit tests good (on many engines it shares a housing with the rail pressure sensor). Replace a faulty fuel rail pressure sensor if scan-tool pressure does not match a mechanical gauge. Repair or reprogram the engine computer only after the wiring and parts check out.

P0090⛽ Fuel / fuel pressureDrive with caution, fix soon

P0090: Fuel Pressure Regulator 1 Control Circuit Open (Meaning, Causes, Fixes)

Q: What does P0090 mean?

P0090 means the engine computer found an open (broken or disconnected) control circuit to the electronic fuel pressure regulator labeled 1. Searches for it are common on Duramax and Chevy Silverado trucks, the Ford 6.7 Power Stroke, Nissan, Infiniti, Hyundai and VW. Damaged wiring or connectors are the first thing to check, followed by the regulator itself, the fuel rail pressure sensor and, last, the engine computer. On many engines the engine computer (PCM) controls fuel pressure with an electronic fuel pressure regulator. OBD-Codes.com explains that the PCM supplies voltage and ground to a small servo motor in the regulator that moves a valve to raise or lower pressure, while a fuel pressure sensor, usually on the fuel rail, reports actual pressure back. The regulator and sensor are often built into one housing with a single connector. P0090 sets when the PCM detects an open control circuit to regulator 1; the 1 is used on systems with more than one regulator and may, but does not always, refer to an engine bank. RepairPal describes P0090 only for diesel engines, saying the PCM uses the regulator to control fuel on the low-pressure side feeding the high-pressure injection pump, and the code sets when the PCM cannot control the regulator. OBD-Codes.com treats it as a generic code for all OBD2 vehicles, listing GMC, Chevy, Chrysler, Dodge, Jeep, Mitsubishi, VW and Toyota. P0091 and P0092 are the circuit low and circuit high versions, and P0089 is the regulator performance code.

Q: Can I keep driving with P0090?

Drive with caution, fix soon. The sources disagree on how serious P0090 is. OBD-Codes.com classifies it as severe, because excessive fuel pressure can cause drivability problems and damage the engine and catalytic converter. RepairPal rates it moderate, meaning it may not threaten safety right away but should be diagnosed within a reasonable time. Either way, get it checked soon and do not ignore power loss or black smoke. The fuel rail can hold high pressure, so OBD-Codes.com warns to turn the ignition off before connecting a fuel pressure gauge and to keep fuel away from hot surfaces or sparks, since it can ignite.

Reviewed 2026-10-24 · Based on 2 cited source(s)

What P0090 means

On many engines the engine computer (PCM) controls fuel pressure with an electronic fuel pressure regulator. OBD-Codes.com explains that the PCM supplies voltage and ground to a small servo motor in the regulator that moves a valve to raise or lower pressure, while a fuel pressure sensor, usually on the fuel rail, reports actual pressure back. The regulator and sensor are often built into one housing with a single connector. P0090 sets when the PCM detects an open control circuit to regulator 1; the 1 is used on systems with more than one regulator and may, but does not always, refer to an engine bank. RepairPal describes P0090 only for diesel engines, saying the PCM uses the regulator to control fuel on the low-pressure side feeding the high-pressure injection pump, and the code sets when the PCM cannot control the regulator. OBD-Codes.com treats it as a generic code for all OBD2 vehicles, listing GMC, Chevy, Chrysler, Dodge, Jeep, Mitsubishi, VW and Toyota. P0091 and P0092 are the circuit low and circuit high versions, and P0089 is the regulator performance code.

Severity: can I keep driving?

Drive with caution, fix soon

The sources disagree on how serious P0090 is. OBD-Codes.com classifies it as severe, because excessive fuel pressure can cause drivability problems and damage the engine and catalytic converter. RepairPal rates it moderate, meaning it may not threaten safety right away but should be diagnosed within a reasonable time. Either way, get it checked soon and do not ignore power loss or black smoke. The fuel rail can hold high pressure, so OBD-Codes.com warns to turn the ignition off before connecting a fuel pressure gauge and to keep fuel away from hot surfaces or sparks, since it can ignite.

Common symptoms

Check engine light on (OBD-Codes.com)
Decreased engine performance (RepairPal)
Increased fuel consumption or reduced fuel efficiency (both sources)
Delayed or hard startup (OBD-Codes.com)
Black smoke from the exhaust (OBD-Codes.com)
Other drivability codes stored along with P0090 (OBD-Codes.com)

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

Open or shorted wiring or connectors in the fuel pressure regulator control circuit (both sources)
Defective fuel pressure regulator (both sources)
Faulty fuel rail pressure sensor (OBD-Codes.com)
Engine computer (PCM) failure or a PCM programming error (both sources)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

Look over the wiring and connectors on top of the engine, especially at the fuel pressure regulator; OBD-Codes.com notes rodents like the warmth there in cold weather and can chew wires.
Read the codes and freeze frame data with a scan tool and write them down, then clear the code and test drive to see if it comes right back (OBD-Codes.com).
If it returns right away, check for voltage and ground at the regulator connector with a multimeter; with no voltage, check the related fuses and relays, and with no ground, check the ground connections using a wiring diagram (OBD-Codes.com).
Look up technical service bulletins (TSBs) for your vehicle before buying parts.

Typical fixes

Repair broken, chewed, shorted or corroded wiring and connectors in the regulator circuit
Replace the electronic fuel pressure regulator if it does not respond to control voltage after the circuit tests good (on many engines it shares a housing with the rail pressure sensor)
Replace a faulty fuel rail pressure sensor if scan-tool pressure does not match a mechanical gauge
Repair or reprogram the engine computer only after the wiring and parts check out

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

Comparing scan-tool fuel pressure with a mechanical gauge and checking that pressure changes with regulator control voltage needs proper gauges and specs (OBD-Codes.com); diesel high-pressure systems especially are best left to a shop
Testing the PCM control circuits with a meter, which OBD-Codes.com says should be done with the modules disconnected to avoid damaging them
PCM replacement or reprogramming

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Is P0090 serious?

The sources differ. OBD-Codes.com calls it severe because excessive fuel pressure can damage the engine and catalytic converter, while RepairPal rates it moderate. Have it diagnosed soon rather than driving on it indefinitely.

Is P0090 only a diesel code?

No. OBD-Codes.com describes it as a generic code for all OBD2 vehicles with an electronic fuel pressure regulator, including gas engines. RepairPal explains it only in diesel terms, where the regulator controls fuel on the low-pressure side feeding the injection pump, and much of the search interest is for Duramax and 6.7 Power Stroke trucks.

Do the sources agree on the cause?

Mostly. Both name the fuel pressure regulator, wiring and the engine computer. OBD-Codes.com adds a faulty fuel rail pressure sensor and PCM programming errors. The symptoms differ: RepairPal lists decreased performance and higher fuel use, while OBD-Codes.com lists delayed startup, black smoke and poorer fuel efficiency.

Sources

Last reviewed 2026-10-24. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.