P0191 on Acura: How to Diagnose & Fix
Fuel Rail Pressure Sensor Circuit Range/Performance
1 Acura model · 1 documented issue · 1 critical
P0191 on Acura by model: symptoms, diagnosis and fix
The Denso-supplied in-tank fuel pump module fitted to the 2016-2020 ILX uses an impeller that was molded with insufficient density and exposed to production solvent drying for too long, which can crack its surface. The impeller absorbs fuel, swells, and interferes with the pump body. The pump then fails to deliver pressure - typically presenting first as a long crank or a hard start, then progressing to an engine stall that can happen at road speed with no warning and no restart. The ILX coverage was expanded twice: an initial campaign covering the 2019 ILX (21V215, itself an expansion of 20V314) was later broadened to cover 2016-2020 ILX under 23V858, all with the 2.4L and 8-speed DCT.
Common Symptoms
- Engine stalls while driving
- Extended cranking before start
- No-start condition
- Whining or absent fuel pump prime noise at key-on
- Check engine light
- Loss of power under load
How to Fix
Free recall remedy under NHTSA 23V858 (Honda campaign codes KGC/KGD); some 2019 cars may instead fall under 21V215. Dealers replace the entire fuel pump module at no charge. Owner notification for the expanded campaign was mailed September 2024. Do not pay for a fuel pump on an ILX without first running the VIN - a private-pay pump module replacement typically runs $700-$1,200.
Sources for this issue (3)
P0191 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0191 mean on a Acura?
P0191 stands for "Fuel Rail Pressure Sensor Circuit Range/Performance." This code sets when the fuel rail pressure sensor's signal is out of its expected range or doesn't match what the computer expects for current conditions. On direct-injection and many modern engines, this sensor reports fuel pressure in the rail so the computer can precisely control fueling and the fuel pump. When the reading is implausible — too steady, erratic, or inconsistent with commanded pressure — this code is set, sometimes with hard starting, hesitation, or reduced power. It generally points to the sensor or its wiring, though an actual fuel-pressure problem can also trigger it. On Acura it is documented across 1 model: ILX.
What are the most common causes of P0191?
The most common causes of P0191 are: Faulty fuel rail pressure sensor, Corroded, loose, or damaged sensor connector, Open, shorted, or high-resistance sensor wiring, Actual fuel pressure out of range (weak pump or regulator), Restricted fuel filter or supply line, Loss of reference voltage or ground from the ECM/PCM, Faulty fuel pressure regulator or control valve. The specific cause varies by vehicle.
How much does it cost to fix P0191 on a Acura?
Repair costs vary widely with the root cause and Acura model; each issue on this page carries its own estimate where one is published.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.