P2291 — Injector Control Pressure Too Low - Engine Cranking
OBD2 code P2291 flags a problem with the fuel delivery and mixture control (injector control pressure too low - engine cranking). Short, gentle driving to a shop is usually possible. Common culprits: faulty fuel pressure regulator, faulty fuel rail pressure sensor or wiring, vacuum or intake leaks skewing the mixture.
powertrain (engine/transmission)
Is it safe to drive?
Drive with caution Drive with caution. Mixture and fuel-pressure faults can cause stalling, hesitation in traffic and — when severe — catalyst damage. Avoid long trips until diagnosed.
How to diagnose with an OBD scanner
- Read the code and freeze frame Connect an OBD2 scanner, confirm P2291 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
- Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
- Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the fuel delivery and mixture control for damage, corrosion, chafing or poor contact.
- Subsystem check Measure fuel pressure at the rail and compare with factory specification at idle and under load.
- Subsystem check Check short-term and long-term fuel trims in live data to see which way the mixture is off.
- Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2291 does not return.
Approximate repair cost
Repair cost depends on which component actually failed. Typical scenarios for P2291 (parts and labor, USD, independent shop rates): Replace the fuel pump: $400–$900; Replace the pressure regulator or sensor: $150–$450; Replace the fuel filter: $80–$200; Clean or replace injectors: $200–$800. Overall, fixing P2291 usually costs between $80 and $900. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.
Common questions
How do I diagnose P2291 myself?
Start with a scan: confirm P2291, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the fuel delivery and mixture control, and verify the suspect component against live data before buying parts.
How much does it cost to fix P2291?
Replace the fuel pump — $400–$900; Replace the pressure regulator or sensor — $150–$450; Replace the fuel filter — $80–$200; Clean or replace injectors — $200–$800. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.
Will P2291 clear itself?
Sometimes P2291 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.
What does OBD2 code P2291 mean?
OBD2 code P2291 flags a problem with the fuel delivery and mixture control (injector control pressure too low - engine cranking). Short, gentle driving to a shop is usually possible. Common culprits: faulty fuel pressure regulator, faulty fuel rail pressure sensor or wiring, vacuum or intake leaks skewing the mixture.
What are the symptoms of P2291?
Drivers most often notice: fuel smell in severe cases, rough idle and hesitation, increased fuel consumption, hard starting or long cranking.
What does P2291 mean?
P2291 is logged by the onboard diagnostics when the fuel delivery and mixture control does not behave as expected. The official definition is “Injector Control Pressure Too Low - Engine Cranking”. This is a powertrain (engine/transmission) category code.
To set P2291, the control module compares live readings of the fuel delivery and mixture control against calibrated limits, usually over several drive cycles. Alongside the code it stores a freeze frame — a snapshot of rpm, load, coolant temperature and vehicle speed at the moment of failure. Reading that snapshot first saves diagnostic time.
Common symptoms of P2291
- fuel smell in severe cases
- rough idle and hesitation
- increased fuel consumption
- hard starting or long cranking
- loss of power under load
What causes P2291?
- weak fuel pump or clogged fuel filter
- vacuum or intake leaks skewing the mixture
- contaminated or incorrect fuel
- faulty fuel pressure regulator
How to diagnose P2291
- Connect an OBD2 scanner, confirm P2291 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
- Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
- Visually inspect the wiring harness and connectors related to the fuel delivery and mixture control for damage, corrosion, chafing or poor contact.
- Measure fuel pressure at the rail and compare with factory specification at idle and under load.
- Check short-term and long-term fuel trims in live data to see which way the mixture is off.
- Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2291 does not return.
How to fix P2291
Start with the cheapest and most common causes before replacing expensive parts:
- Replace the fuel pump — $400–$900
- Replace the pressure regulator or sensor — $150–$450
- Replace the fuel filter — $80–$200
- Clean or replace injectors — $200–$800
How much does it cost to fix P2291?
Repair cost depends on which component actually failed. Typical scenarios for P2291 (parts and labor, USD, independent shop rates):
- Replace the fuel pump: $400–$900
- Replace the pressure regulator or sensor: $150–$450
- Replace the fuel filter: $80–$200
- Clean or replace injectors: $200–$800
Overall, fixing P2291 usually costs between $80 and $900. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.
Can you drive with P2291?
Drive with caution. Mixture and fuel-pressure faults can cause stalling, hesitation in traffic and — when severe — catalyst damage. Avoid long trips until diagnosed.