OBD-II Code P2291: Injector Control Pressure Too Low While Cranking

What Does P2291 Mean?

P2291 means the Powertrain Control Module (PCM) detects insufficient fuel pressure to safely start the engine. The PCM requires a minimum pressure (typically 500 PSI) to activate the fuel injectors. This code sets when pressure falls below that threshold during the cranking phase. While most common on high-pressure diesel engines, it also applies to Gasoline Direct Injection (GDI) vehicles.

Technical definition: Injector Control Pressure Too Low - Engine Cranking. The injector control pressure (ICP) or fuel rail pressure (FRP) fell below the manufacturer's specified minimum threshold while the engine cranked, preventing startup.

Can I Drive With P2291?

No — Do Not Drive. Your engine will likely not start. If it does manage to start, it will stall unexpectedly, making the vehicle extremely unsafe to drive.

Common Causes

• Low or Incorrect Engine Oil (HEUI Systems) (Very Common) — On Ford 7.3L and 6.0L Powerstroke engines, high-pressure engine oil powers the fuel injectors. Low, degraded, or incorrect viscosity oil prevents the high-pressure oil pump (HPOP) from building the 500 PSI required to start.
• Weak Batteries or Slow Cranking Speed (Common) — The engine must spin the high-pressure pump at 150+ RPM to build pressure. Weak batteries or a failing starter prevent the pump from reaching the minimum pressure threshold, triggering P2291 even if the fuel system is perfect.
• Failed High-Pressure Oil Pump (HPOP) or Fuel Pump (HPFP) (Common) — Internal wear or catastrophic failure prevents the pump from generating pressure. This is notorious on Ford 6.0L (HPOP) and 2011-2016 GM Duramax / Ford 6.7L (CP4 HPFP) engines.
• Failed Injector Pressure Regulator (IPR) or Fuel Control Actuator (FCA) (Common) — This valve regulates pump pressure. If it sticks open, fails electronically, or clogs with debris, pressure bleeds off during cranking instead of building.
• Failed Injector Control Pressure (ICP) or Fuel Rail Pressure (FRP) Sensor (Less Common) — A faulty sensor sends a false low-pressure signal to the PCM. Unplugging the sensor forces the PCM to use a default value; if the engine starts, the sensor is bad.
• High-Pressure Fuel/Oil System Leaks (Less Common) — Internal leaks prevent pressure buildup. Common points include injector O-rings, standpipes and dummy plugs (Ford 6.0L), or the pressure relief valve.
• Clogged Fuel Filters or Starved Lift Pump (Less Common) — Severely clogged filters or a weak low-pressure lift pump starve the high-pressure pump. Metal shavings in the filter indicate catastrophic HPFP failure.
• Wiring Harness Issues (Less Common) — Chafed, melted, or corroded wiring to the ICP/FRP sensor or IPR/FCA valve causes signal loss or shorts, preventing system operation.
• Failed HPFP Cam Follower (GDI Engines) (Less Common) — On Gasoline Direct Injection engines (like VW/Audi 2.0T), the HPFP is driven by a camshaft follower. Severe wear reduces pump plunger travel, causing low pressure.
• Faulty Powertrain Control Module (PCM) (Rare) — Internal PCM failure or software corruption prevents it from reading sensor data or commanding the pressure regulator.

Symptoms

• Engine cranks but will not start — The starter turns the engine over, but injectors do not activate due to insufficient pressure.
• Extended cranking time before starting — The engine takes significantly longer to start as the system struggles to build minimum pressure.
• Check Engine Light is on — The PCM illuminates the MIL and stores the P2291 code.
• Engine stalls after starting or at idle — Unstable pressure drops below the required level, causing rough running and stalling.
• Excessive smoke from exhaust on startup — Poor fuel atomization from low injection pressure causes black or white smoke.
• Unusual noises from the engine — Rattling injectors or a whining/grinding noise from the engine valley indicates a failing HPFP.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this code.

Common Fixes & Costs

• Change Engine Oil and Filter / Correct Oil Level — Parts: $50-$150, Labor: $50-$100, ~0.5 hr book time (DIY)
• Replace Batteries — Parts: $300-$500 (for a pair), Labor: $50-$100, ~0.5 hr book time (DIY)
• Replace Injector Control Pressure (ICP) / Fuel Rail Pressure (FRP) Sensor — Parts: $120-$250, Labor: $100-$200, ~1.5 hr book time (DIY)
  Ford 6.0L Powerstroke (2003-2004): OEM
  Ford 6.0L Powerstroke (2004.5-2007): OEM
• Replace Injection Pressure Regulator (IPR) / Fuel Control Actuator (FCA) — Parts: $150-$350, Labor: $150-$600, ~2.0 hr book time (Intermediate)
  Ford 6.0L Powerstroke (2004.5-2007): OEM
  Dodge Ram 5.9L/6.7L Cummins: OEM
• Replace High-Pressure Oil Pump (HPOP) or High-Pressure Fuel Pump (HPFP) — Parts: $800-$2,500, Labor: $1,000-$2,500, ~8.0 hr book time (Professional)
  Ford 6.0L Powerstroke HPOP (2004.5-2007): OEM
  Ford 6.7L Powerstroke HPFP (CP4, 2011-2014): OEM
  GM 6.6L LML Duramax HPFP (CP4, 2011-2016): OEM
• Full Fuel System Replacement (After HPFP/CP4 Failure) — Parts: $3,000-$5,000, Labor: $3,000-$6,000, ~18.0 hr book time (Professional)
• Replace HPFP Cam Follower (GDI Engines) — Parts: $30-$80, Labor: $150-$400, ~1.5 hr book time (Intermediate)
  VW/Audi 2.0T TFSI: OEM

DIY vs Professional

• Change Engine Oil and Filter / Correct Oil Level — Beginner:
• Replace Batteries — Beginner:
• Replace ICP/FRP Sensor or IPR/FCA Valve — Beginner:
• Replace HPFP Cam Follower (GDI) — Beginner:
• Replace High-Pressure Oil Pump (HPOP) — Beginner:
• Replace High-Pressure Fuel Pump (HPFP) / Full Fuel System — Beginner:

Used vs. New Parts: Buying Guide

When a used part is worth it: Never buy a used high-pressure fuel or oil pump. Internal disintegration contaminates the part, making used pumps a massive liability.

Donor-vehicle mileage cap: roughly under 20000 miles for the part to have meaningful remaining life.

Donor quality checklist:

• Only consider used hard parts (like fuel rails) from low-mileage, non-engine-wrecked vehicles.
• Buy new or Bosch-remanufactured pumps. Avoid cheap, no-name remanufactured units.
• Verify the exact OEM part number, as pump designs change frequently.

Decision logic:

• If The part is a High-Pressure Fuel Pump (HPFP) or High-Pressure Oil Pump (HPOP). → Buy new OEM or high-quality remanufactured. A used part risks destroying the entire fuel system.
• If The part is an electronic sensor (ICP) or regulator (IPR). → Buy new OEM. Used sensors in high-heat environments fail quickly and complicate diagnostics.

Warranty tradeoff: Used parts offer 30-90 day warranties. New OEM or Bosch remanufactured pumps carry 1-year+ warranties, which is critical given the 8-18 hour labor times.

Worst-case if a used part fails: $10,000-$17,000. A failed cheap remanufactured CP4 pump sends metal debris everywhere, requiring replacement of the pump, injectors, rails, lines, and tank cleaning.

What Happens If You Wait — Timeline

1. First Occurrence: Intermittent extended crank times. The engine takes an extra 2-3 seconds to start. No codes set yet. (MPG impact: 0%% · Added cost: $0)
2. Weeks to Months: Cranking times lengthen consistently. Occasional rough idle on startup. P2291 stores as 'pending'. (MPG impact: 0-5%% · Added cost: $50-$150 in starter/battery wear.)
3. Days to Weeks Later: First crank-no-start event. P2291 sets as 'active' and the Check Engine Light illuminates. Vehicle is highly unreliable. (MPG impact: N/A% · Added cost: $300-$700 for a tow and accelerated starter/battery damage.)
4. Immediate to Days Later: Complete crank-no-start. If caused by a CP4 pump, every crank attempt grinds more metal into the fuel system. (MPG impact: N/A% · Added cost: $8,000-$15,000 for full fuel system replacement due to metal contamination.)

Cost of Not Fixing It

• Immediate: Vehicle will not start, leaving you stranded. (Added cost: $100-$300 for a tow.)
• Days to Weeks: Repeated cranking drains batteries and overheats the starter motor, causing premature failure. (Added cost: $300-$800 for new batteries and a starter.)
• Ongoing: Driving with a failing high-pressure fuel pump (HPFP) circulates metal debris, destroying the entire fuel system. (Added cost: $8,000-$15,000 for a full fuel system replacement.)

Diagnosis Steps

1. Check Engine Oil Level and Condition (HEUI Systems)
   For Ford 7.3L/6.0L Powerstroke engines, ensure the engine oil is full and clean. Low oil physically prevents the HPOP from building pressure.
   Tools: Clean rag or paper towel (Beginner)
2. Perform Battery and Charging System Test
   Load test both batteries. Voltage must remain above 10.0V while cranking, and cranking speed must exceed 150 RPM. Slow cranking prevents pressure buildup.
   Tools: Digital Multimeter, Battery Load Tester (Beginner)
3. Perform a Full System Scan and Review Freeze Frame Data
   Record P2291, related codes (P0087, P2290), and freeze frame data to see exact sensor values when the fault occurred.
   Tools: OBD-II Scanner (Beginner)
4. Monitor Live Data While Cranking
   Watch the Injector Control Pressure (ICP) or Fuel Rail Pressure (FRP) PID while cranking. It must rise to at least 500 PSI. If it stays near zero, you have a pressure generation problem.
   Tools: OBD-II Scanner with Live Data (Intermediate)
5. Test the ICP/FRP Sensor (The 'Unplug' Test)
   With the key off, unplug the ICP or FRP sensor. Try to start the engine. If it starts, the PCM defaulted to a pre-set pressure, proving the sensor or its wiring is faulty.
   Tools: Hands (No tools required) (Intermediate)
6. Inspect Fuel Quality and Filters
   Check fuel filters for clogging. Inspect the filter housing for metallic glitter. Metal shavings confirm a catastrophic high-pressure fuel pump failure.
   Tools: Filter wrench, clean container (Intermediate)
7. [PRO TIP] Monitor IPR/FCA Duty Cycle
   While cranking, watch the IPR/FCA duty cycle. If the PCM commands a high duty cycle (75-85%) but pressure remains low, the PCM is trying its hardest against a large leak or weak pump.
   Tools: Advanced OBD-II Scanner (Intermediate)
8. Inspect Wiring Harness
   Visually inspect wiring to the ICP/FRP sensor, IPR/FCA valve, and pump for chafing, melting, or rodent damage.
   Tools: Flashlight, Mirror (Intermediate)
9. [ADVANCED] ICP/FRP Sensor Electrical Test
   Back-probe the sensor connector. Key On, Engine Off (KOEO) signal voltage should be ~0.2-0.25V. While cranking, it should rise to at least 0.8V. 0V or 5V indicates a short or open circuit.
   Tools: Digital Multimeter, Wiring Diagram (Advanced)
10. [ADVANCED] IPR/FCA Resistance Test
    Measure internal resistance of the disconnected IPR/FCA. A Ford 6.0L IPR reads 5.0-15.0 ohms. A Cummins FCA reads 3-5 ohms. 0 ohms (short) or OL (open) means the part failed.
    Tools: Digital Multimeter (Advanced)
11. Perform a High-Pressure System Leak Test
    Introduce 100 PSI of regulated compressed air into the ICP port using a block-off tool. Listen for hissing at the oil fill cap (injector O-rings) or valve covers (standpipes/dummy plugs).
    Tools: High-pressure test kit, air compressor (Advanced)

When This Code Triggers (Freeze-Frame Conditions)

• Engine RPM: 150-300 RPM (Engine Cranking. The code sets because pressure fails to build at this pre-start speed.)
• Vehicle Speed: 0 mph (Vehicle is stationary during startup.)
• Engine Coolant Temp (ECT): Ambient to warm (Occurs at any temperature, but cold starts exacerbate issues due to thicker oil (HEUI systems) or fuel gelling.)
• Fuel System Status: Open Loop (The engine has not started or warmed up enough to use oxygen sensor feedback.)

Related Codes

• P2290 — Indicates low pressure while the engine is *running*. P2291 sets *only* during cranking. P2291 means no start; P2290 means stalling or low power.
• P0087 — A general low fuel pressure code. When paired with P2291 on common-rail diesels, it strongly suggests a failed HPFP.
• P0093 — Indicates a sudden, large fuel leak while running. The underlying major leak prevents pressure buildup during subsequent crank attempts.
• P2285 — Points to an *electrical* short or failure in the ICP sensor circuit. P2291 indicates a *mechanical* pressure problem read by a functioning sensor.
• P1291 — Ford-specific code for an injector short to ground. This electrical fault prevents injectors from firing, mimicking a pressure issue.

Climate & Environmental Factors

• Cold Weather: Cold thickens engine oil, preventing HEUI HPOPs from building pressure. Diesel fuel gels below 20°F, clogging filters and starving the HPFP.
• Fuel Quality & Blends: Summer-blend diesel used in winter increases gelling risk. Biodiesel blends gel at warmer temperatures than standard diesel.
• Humidity: High humidity promotes water condensation in the fuel tank. Water destroys high-pressure fuel pumps and injectors.

How to Talk to a Mechanic About This Code

Say this: "I have a crank-no-start condition with a P2291 code. Please start with the basics: check oil level, test the batteries and cranking RPM, and monitor ICP/FRP live data while cranking. Do not replace any major parts without my authorization based on the diagnostic data."

This directs the technician to rule out simple, cheap fixes before assuming the most expensive one, protecting you from a 'parts cannon' approach.

Avoid saying:

• 'My truck won't start, can you fix it?'
• 'I think I need a new fuel pump.'
• 'Just do whatever it takes to get it running.'

Questions to ask before authorizing the repair:

• What were the ICP/FRP pressure and IPR/FCA duty cycle readings while cranking?
• Have you checked the fuel filter for metal shavings?
• If recommending a sensor replacement, did unplugging it allow the engine to start?
• If recommending a high-pressure pump, what tests ruled out leaks or sensor issues?
• What is the warranty on the parts and labor?

Where to Take It: Dealer vs Independent vs Chain

• Dealer: Recommended only if the vehicle is under warranty. Otherwise, a specialist is a better value.
  Best for: Vehicles under powertrain or emissions warranty., Vehicles covered by manufacturer extended warranty programs (e.g., VW TDI or GM LML CP4 pump failures).
  Downsides: Highest labor rates., Quick to recommend a full, expensive fuel system replacement without exploring all diagnostic avenues. (Typical cost: +50% vs. baseline)
• Independent Shop: Best fit. An independent diesel specialist is the ideal choice for diagnosing P2291.
  Best for: Out-of-warranty diesel trucks., Shops that explicitly state they are 'Diesel Specialists'., Getting a second opinion on a dealer's expensive diagnosis.
  Downsides: Quality varies. General auto repair shops lack the specific tools for high-pressure fuel systems. (Typical cost: +0% vs. baseline)
• Chain Shop: AVOID for diagnosis. Only use a chain for a simple battery replacement after confirming they are the cause.
  Best for: Battery testing and replacement.
  Downsides: Technicians lack specialized training and equipment for high-pressure diesel diagnostics., High risk of misdiagnosis. (Typical cost: -10% vs. baseline)

When to Walk Away From the Repair

If the estimated repair cost for a catastrophic failure exceeds 50-60% of the truck's private-party market value, seriously consider selling the vehicle as-is.

• Car worth $25000, fix is $12000: Borderline. The repair cost is nearly half the vehicle's value. Get a second opinion.
• Car worth $30000, fix is $1500: Fix it. The repair is for a component like an HPOP or sensor, well below the walk-away threshold.
• Car worth $15000, fix is $10000: Walk away. The repair cost is too high relative to the vehicle's value.

What Scan Tool You Need for This Code

Minimum: A scanner that displays live data PIDs for the high-pressure fuel/oil system (ICP/FRP Pressure, IPR/FCA Duty Cycle, Engine RPM).

A basic $20 code reader only shows 'P2291'. It cannot show the live pressure data needed to determine *why* the code is set, forcing you to guess.

Budget: FORScan Lite with OBDLink EX/MX+ Adapter (~$85) — The most powerful budget option for Ford. Reads all Ford-specific PIDs like ICP and IPR duty cycle essential for Powerstroke diagnostics.

Mid-range: BlueDriver Pro or Autel MaxiCheck MX808S (~$100-350) — Offers robust live data graphing. The Autel MX808S adds bidirectional controls to command the IPR/FCA valve directly.

Professional: Autel MaxiCOM MK906BT or Launch X431 Series (~$600-1200) — Provides full bidirectional control and OEM-level diagnostics to definitively test pumps, regulators, and sensors.

Rent vs buy: Buy. A basic parts store loaner tool lacks manufacturer-specific live data. A capable scanner pays for itself by avoiding one misdiagnosis.

How to Clear the Code After You Fix It

1. Use an OBD-II scan tool to clear P2291 and related fault codes.
2. Ensure the fuel tank is between 30% and 70% full.
3. Perform a complete drive cycle to run readiness monitor self-tests.

Drive cycle (~30 minutes): Cold start the vehicle (after sitting 8+ hours). Idle for 3 minutes. Drive at a steady 55-60 mph for 10 minutes. Perform several coasting decelerations. Drive in stop-and-go traffic for 10 minutes. Park and idle for 2 minutes before shutting down.

Readiness monitors affected: Comprehensive Component Monitor, Fuel System Monitor, Misfire Monitor

Before emissions retest: drive at least 50 miles to fully set monitors.

Watch out for:

• Clearing the code without a drive cycle leaves monitors incomplete, causing an automatic emissions failure.
• The code returns immediately upon the next crank if the mechanical or electrical fault remains.

Will This Fail Emissions / State Inspection?

Yes — this code typically fails an OBD-II emissions inspection.

• California: An illuminated Check Engine Light is an automatic failure. A full drive cycle must set all readiness monitors before a re-test.
• New York: Active P2291 codes cause an immediate failure of the NYS DMV OBD-II emissions inspection.
• Texas: In the 17 emissions-testing counties, an active P2291 fails the OBD-II portion of the annual safety inspection.

Most Commonly Affected Vehicles

• Ford F-250/F-350 Super Duty with 6.0L Powerstroke (2003-2007) — Extremely common due to HPOP, IPR valve, and ICP sensor failures. The 'unplug ICP' test is highly effective here.
• Ford F-250/F-350 Super Duty with 6.7L Powerstroke (2011-2019) — Uses the Bosch CP4 pump, notorious for catastrophic failure that contaminates the entire fuel system. Aftermarket disaster prevention kits are highly recommended.
• Chevrolet / GMC Silverado/Sierra 2500HD/3500HD with 6.6L LML Duramax (2011-2016) — Also uses the failure-prone Bosch CP4 pump. Failures trigger P0087 and P2291, requiring a $10,000+ full fuel system replacement.
• Dodge / Ram 2500/3500 with 6.7L Cummins (2007-2024) — More reliable due to the Bosch CP3 pump. P2291 here usually points to a failing lift pump, bad FCA, or clogged fuel filters.
• Ford F-250/F-350 Super Duty with 7.3L Powerstroke (1999-2003) — IPR valve and ICP sensor are common failure points causing a no-start.
• Volkswagen Jetta, Golf, Passat with 2.0L TDI (CJAA, CBEA) (2009-2014) — Bosch CP4 HPFP failure contaminates the fuel system with metal debris, requiring extensive repairs.
• Audi A3, Q5, A4 with 2.0T TFSI (GDI) (2009-2016) — The cam follower driving the high-pressure fuel pump wears out, reducing pump stroke and triggering P2291.
• BMW 335d, X5 xDrive35d with M57 Diesel (2009-2013) — HPFP or pressure regulating valve issues lead to a no-start condition.

Manufacturer-Specific Notes

• Ford (Powerstroke): The 7.3L/6.0L HEUI system relies entirely on engine oil pressure to fire injectors. On the 6.7L, aftermarket 'Disaster Prevention Kits' are vital to protect the fuel system from CP4 pump explosions.
• General Motors (Duramax): On 2011-2016 LML engines, P2291 is often a death sentence for the Bosch CP4.2 pump. The only correct repair is a full fuel system replacement.
• Dodge / Ram (Cummins): Diagnosis should focus on the lift pump supply pressure and the Fuel Control Actuator (FCA) before suspecting the robust CP3 high-pressure pump.
• Volkswagen / Audi (TDI): VW offered an extended warranty (Campaign 23O6) for the HPFP on certain 2009-2014 models due to catastrophic failure rates.

Real Owner Stories

2006 Ford F-250 6.0L Powerstroke - The Simple Fix

Truck cranked but would not start after sitting for a week, throwing P2291. Owner feared a major HPOP failure.

What they tried:

1. Checked batteries, which were strong.
2. Scanned live data, showing ICP pressure stuck below 200 PSI during cranking.
3. Checked the engine oil dipstick.

Outcome: The engine oil level barely registered on the dipstick. Adding two gallons of 15W-40 oil allowed the truck to start immediately. The code did not return.

Lesson: On HEUI engines, always check the engine oil level first. The high-pressure oil system cannot build pressure to fire injectors if oil is low.

2012 GMC Sierra 2500HD 6.6L LML Duramax - Misdiagnosis Chain

Truck shut off while driving and would not restart, throwing P2291.

What they tried:

1. Replaced the low-pressure lift pump (no change).
2. Replaced the fuel pressure regulator (no change).
3. Inspected the fuel filter housing.

Outcome: The fuel filter housing was full of metal shavings. The CP4 pump had failed catastrophically, requiring a $12,000 full fuel system replacement. Initial parts replacement was a waste of money.

Lesson: On CP4-equipped trucks, the first diagnostic step is checking the fuel filter for metal shavings. If metal is present, stop diagnostics and plan for a full system replacement.

2012 Ford F-250 6.7L Powerstroke - The Elusive Electrical Gremlin

After a full fuel system replacement for a failed CP4, the truck still had a crank-no-start condition with P2291.

What they tried:

1. Verified the new CP4 pump was functional.
2. Checked lift pump pressure.
3. Traced the wiring harness.

Outcome: The pigtail connector for the fuel rail pressure sensor was damaged during the engine work. Replacing the $40 pigtail resolved the issue.

Lesson: If codes return after a major repair, inspect all wiring harnesses handled during the job. A damaged connector mimics a major mechanical failure.

How to Prevent This Code From Triggering

• Perform frequent oil changes with correct viscosity oil (HEUI engines). (Every 3,000-5,000 miles) — HEUI systems shear oil under intense pressure. Clean oil prevents injector stiction and ensures the HPOP functions correctly.
• Use a quality diesel fuel additive with added lubricity. (Every fill-up) — Ultra-low sulfur diesel lacks lubricity, increasing wear on high-pressure pumps. Additives restore lubricity and prevent pump failure.
• Install a 'Disaster Prevention Kit' on CP4-equipped trucks. (Once, as a proactive upgrade) — Reroutes pump case fuel through a filter. If the pump fails, debris is caught instead of destroying the $10,000+ fuel system.
• Replace fuel filters at or before recommended intervals. (Every 10,000-15,000 miles) — Prevents pump starvation and provides a regular opportunity to inspect for water or metal shavings.
• Use an anti-gel fuel additive in cold climates. (During winter months) — Prevents diesel from turning to a waxy solid that clogs filters and starves the HPFP.

Frequently Asked Questions

Can I drive my truck with a P2291 code?

No. The engine will likely not start. If it does, it runs unreliably and stalls unexpectedly, creating a major safety hazard.

Is P2291 always an expensive fix?

Not always. Simple causes like low engine oil or weak batteries cost under $300 to fix. However, a catastrophic high-pressure pump failure requires a full fuel system replacement exceeding $10,000.

Can a bad battery cause P2291?

Yes. The high-pressure pump requires a minimum engine cranking speed (typically >150 RPM) to build pressure. Weak batteries cause slow cranking, preventing the pump from hitting its target and triggering the code.

What are the metal shavings in my fuel filter I've heard about?

Metal shavings in the fuel filter confirm a catastrophic failure of the high-pressure fuel pump (like the Bosch CP4). Do not crank the engine further. The entire fuel system is contaminated and requires complete replacement.

What is a CP4 Disaster Prevention Kit?

This aftermarket kit modifies the fuel return path on CP4-equipped trucks. If the pump fails, it routes metal debris back to the fuel tank filters instead of the high-pressure rails and injectors. This turns a $15,000 system replacement into a $2,000 pump replacement.

What are the most common misdiagnosis mistakes for P2291?

The biggest mistake is replacing the expensive high-pressure pump before ruling out low oil, weak batteries, or a faulty ICP/FRP sensor. Another error is replacing a catastrophically failed pump without replacing the contaminated injectors and lines, guaranteeing a repeat failure.

Can a gasoline engine get a P2291 code?

Yes, though less common. Modern Gasoline Direct Injection (GDI) engines use a high-pressure fuel pump driven by the camshaft. A worn cam follower or failed pump triggers P2291 by reducing fuel pressure during startup.

Key Takeaways

• Code P2291 indicates the Powertrain Control Module (PCM) detects less than the 500 PSI of fuel pressure required to start the engine.
• Before buying expensive parts, verify your batteries maintain at least 10.0V under load and crank the engine at 150+ RPM.
• On Ford 6.0L and 7.3L HEUI engines, check the engine oil dipstick immediately, as low oil physically prevents the high-pressure pump from firing the injectors.
• If you find metallic glitter in the fuel filter housing of a CP4-equipped diesel (like a 2011-2016 Duramax), stop cranking immediately to prevent further $10,000+ fuel system contamination.