Fuel Rail Pressure Sensor Circuit Range/Performance
The DURAMAX-P0191 (Duramax) diesel fault code means: Fuel Rail Pressure Sensor Circuit Range/Performance. This is a serious severity code.
- Keep driving?
- No — stop driving
- DIY difficulty
- advanced
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What Are the Symptoms of DURAMAX-P0191?
- Check Engine Light on
- Hard starting or long cranking
- Loss of power or reduced power mode
What Causes DURAMAX-P0191? (Most Likely First)
- Rail pressure sensor reading incorrectly High
- Wiring or connector fault at the sensor Moderate
- Actual rail pressure problem from the pump or regulator Moderate
- Shared sensor reference voltage problem Low
Can I Still Drive with DURAMAX-P0191?
No — stop driving. DURAMAX-P0191 is rated serious severity. Continuing to drive in this state risks further damage — get it looked at before your next trip.
Frequently Asked Questions
What does P0191 mean on a Duramax?
P0191 means Fuel Rail Pressure Sensor Circuit Range/Performance. The rail pressure sensor is reporting, but its reading does not make sense against what the engine computer expects.
Is P0191 a Duramax-specific code?
No. P0191 is a generic OBD-II code defined by SAE J2012, so it means the same thing on any vehicle that sets it. The exact conditions GM uses to set it on its diesels are in GM service information.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose DURAMAX-P0191?
With the engine off and pressure bled down, check that the sensor reads near zero.
Compare desired and actual rail pressure on a scan tool.
Check the sensor reference voltage, ground and signal circuits.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines P0191 as a generic OBD-II code)
P0191 on Other Platforms
The same code ID appears across other engines, vehicles, and equipment. Diagnostic flow varies by platform — see the matching breakdown:
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