Deutz Fault Code

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SPN 91 FMI 3

Engine stuck at idle; No throttle response; Service lamp on.

System

Not specified

Symptom

Engine stuck at idle; No throttle response; Service lamp on.

Diagnosis & fix steps

Accelerator Pedal Signal High LOGIC: Signal voltage > 4.5V (Open circuit or short to battery). ACTION: Check the 6-pin pedal connector for moisture. Verify 5V supply and ground. FIX: Replace pedal assembly or repair harness.

Red Seal field insights

These pedals use two sensors for safety. If they don't "agree," the engine will default to idle. Check the "APP1" and "APP2" values in your scan tool.

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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