Global Fault Code

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P0171

Shaking at idle; Lean hesitation; Poor acceleration.

System

Fuel

Symptom

Shaking at idle; Lean hesitation; Poor acceleration.

Diagnosis & fix steps

System Too Lean (Bank 1). LOGIC: Oxygen sensor reports too much air/too little fuel; fuel trims are maxed out. ACTION: Check for vacuum leaks or a dirty MAF sensor. FIX: Clean MAF Sensor or replace a cracked Intake Boot.

Red Seal field insights

In the PH, "dirty" air often fouls the MAF wire. Clean it with specialized spray before replacing any expensive sensors.

Same code keeps coming back?

That's a program problem, not a part problem. Book a 30-minute uptime review with Grant, a Red Seal Heavy Duty Technician.

Book an uptime review

Read before you touch anything

  • This is general reference information, not a repair manual. It is for trained, qualified technicians.
  • Fault codes, meanings and procedures vary by model, serial number and software version. Confirm the code and the procedure against the manufacturer's service manual before acting.
  • Follow the OEM service manual, torque specs and your site's safety procedures: lockout/tagout, block raised equipment, relieve hydraulic, fuel and air pressure, and let hot systems cool.
  • You use this information at your own risk. Adventure Mechanical and AM Fleet Integrity accept no liability for damage, injury, downtime or loss arising from its use.
  • Not affiliated with or endorsed by any manufacturer. Brand names are used only to identify the equipment a code applies to.

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