Error code

OBD2 P0291

OBD2P0291
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Cylinder 11 Injector Circuit Low.

Severity

moderateCan be driven, but performance will suffer with reduced power and potential engine damage if not addressed.

Summary

P0291 indicates a low voltage issue with the fuel injector circuit for cylinder number 11 in the engine.

Symptoms

  • Engine knock or pinging
  • Decreased power, especially during acceleration
  • Reduced fuel economy

Common Causes

  • Faulty fuel injector (cylinder 11)
  • Corroded or loose electrical connectors in the fuel injector circuit
  • Wiring harness issues between the PCM and cylinder 11's fuel injector
  • Low battery voltage affecting the entire system

Diagnosis

  1. Inspect electrical connectors for corrosion or looseness
  2. Check wiring harness continuity and resistance
  3. Verify fuel injector operation using a voltmeter

Fixes

  • Replace faulty fuel injector or clean it with a direct injector flushing kit

FAQ

What should I do if the P0291 code is set?

Start by checking electrical connections and wiring harness for cylinder 11's fuel injector. If issues are found, repair or replace as needed.

Can other codes be related to P0291?

Yes, codes like P0301 (misfire in cylinder 11) and P0293 (fuel-related issue in cylinder 11) can indicate similar problems.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

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