P0190 means Fuel Rail Pressure Sensor A Circuit. The computer has detected an electrical fault in the fuel rail pressure sensor circuit. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0190 means
Modern engines measure boost and fuel rail pressure and compare them with a desired value calculated from engine speed, load and throttle. When actual pressure falls short of desired for long enough, the computer sets a code and often reduces power to protect the engine. Watching desired and actual values side by side on a scan tool shows whether the shortfall is constant or only appears under load.
P0190 symptoms
- Hard starting or no-start
- Reduced-power mode
- Stalling
Common causes of P0190
- Damaged connector or wiring
- Failed rail pressure sensor
- Shorted 5-volt reference
How to diagnose P0190
- Inspect the connector and wiring
- Check reference voltage and ground
- Check the sensor reading with the engine off
Can you drive with P0190?
Not reliably; repair before relying on the vehicle.
P0190 tips
Rail pressure sensors are often the first thing disturbed during fuel system work. Check that the connector is latched and the wiring is not stretched or pinched. With the engine off and sitting, rail pressure should bleed toward zero; a sensor that reports high pressure with the engine off, or no reading at all, has a circuit or sensor fault. Some rail sensors are only sold with the rail, so price the part before condemning it.
Will P0190 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0190 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0191 | Fuel Rail Pressure Sensor A Circuit Range/Performance |
| P0193 | Fuel Rail Pressure Sensor A Circuit High |
| P0087 | Fuel Rail/System Pressure Too Low |
Guides that help
When it is more than a sensor
Our superchargers page lists supercharger kits, and diesel owners can read the 6.7 Cummins turbo guide. If a failed turbo or fuel pump has damaged the engine, compare engines by code on our engines page.
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