JCB Fault Code

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P0404

Limp Mode.

Variant 1

System

Not specified

Symptom

Limp Mode.

Diagnosis & fix steps

LOGIC: EGR Valve position is out of range. ACTION: Remove EGR valve and check for carbon "coking." Use a diagnostic tool to perform a "Valve Sweep" test.

Red Seal field insights

Pro-Tip: JCBs are notorious for carbon buildup if they idle too much. If the valve is stuck, soak it in carb cleaner—don't pry on the butterfly or you'll snap the gear.

Variant 2

System

Emissions (EGR)

Symptom

Low Power / Black Smoke.

Diagnosis & fix steps

LOGIC: EGR Valve Position Error. ACTION: Remove the EGR valve and check for carbon "coking." Perform a "Manual Reset" of the EGR adaptations via the JCB ServiceMaster tool.

Red Seal field insights

PRO-TIP: If the valve is physically stuck, don't force it. Soak the butterfly in carbon cleaner. If the internal gears are stripped, you will hear a "clicking" at key-on.

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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