JAC Fault Code
Free · no signupP0404
Hesitation at 1,500–2,000 RPM / Smoke
System
Emissions / EGR
Symptom
Hesitation at 1,500–2,000 RPM / Smoke
Diagnosis & fix steps
LOGIC: Exhaust Gas Recirculation (EGR) Position Feedback Drift.
ACTION: Remove electronic EGR valve assembly. Scrape out hard carbon packing on the stainless poppet spindle and clean potentiometer feedback tracks. Perform EGR adaptation reset.
Red Seal field insights
High Ash Sooting: Low-tier regional diesel fuels produce heavy wet soot that jams the EGR pintle shaft before it completes its power-down self-cleaning sweep.
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.
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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