What does this code mean?
The wording below belongs to the named make and communication. Match the complete code, reporting module, model year and engine before applying it.
A code identifies a detected condition, not a part that must automatically be replaced.
Manufacturer wording
Source wording can vary by vehicle and suffix. It is shown as written, not as a universal diagnosis.
P0191FUEL RAIL PRESSURE SENSOR CIRCUIT PERFORMANCEManufacturer communications
4Original wording in English
FORD, MERCURY
Reported code forms P0191
DRIVEABILITY-MALFUNCTION INDICATOR LAMP (MIL) WITH P0316 WHEN USING WINTER BLEND REFORMULATED FUELS AT TEMPERATURES ABOVE 50 DEGREES F (10 DEGREES C) DURING WINTER MONTHS-ROUGH OR ROLLING IDLE AFTER HOT SOAK RESTART…
FORD, MERCURY
Reported code forms P0191
SOME VEHICLES EQUIPPED WITH A 3.0L 4V ENGINE MAY EXHIBIT A MALFUNCTION INDICATOR LAMP ILLUMINATION WITH A DIAGNOSTIC TROUBLE CODE P0191 (FUEL RAIL PRESSURE SENSOR CIRCUIT PERFORMANCE) IN MEMORY. *TT
FORD, MERCURY
Reported code forms P0191
SOME VEHICLES MAY EXHIBIT A ROUGH ENGINE IDLE, ENGINE IDLE ROUGHNESS OR IDLE RPM DIP WITH THE AIR CONDITIONER ON, A DIAGNOSTIC TROUBLE CODE P0191 OR 1-2 UPSHIFT. *TT
FORD, MERCURY
Reported code forms P0191
SOME VEHICLES MAY EXHIBIT VARIOUS DIAGNOSTIC TROUBLE CODES (DTCS) P1233, P1235, P1237, P0191) AND / OR DRIVEABILITY / TRANSMISSION SHIFTING CONCERNS DUE TO WIRING THAT HAS BECOME CHAFED ON THE TOP OF THE TRANSMISSION…
Check vehicle applicability
2A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
Before replacing a part
Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.