What does Mitsubishi fault code P0403 / P0405 mean?

Q: What does Mitsubishi fault code P0403 / P0405 mean?

P0403 / P0405 indicates: Rough idle; "Check Engine" and "VSC" lights; Engine surging. Fix: EGR Volume Control Circuit / Position Sensor Low. LOGIC: The ECU detects an electrical fault in the EGR motor winding or the position sensor signal is out of range. ACTION: 1. Unplug EGR motor; check for corrosion in pins. 2. Check resistance of motor windings. 3. Check for carbon buildup jamming the valve open. FIX: Replace the EGR Valve assembly or repair the harness connector.

Mitsubishi Fault Code

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P0403 / P0405

Rough idle; "Check Engine" and "VSC" lights; Engine surging.

System

Not specified

Symptom

Rough idle; "Check Engine" and "VSC" lights; Engine surging.

Diagnosis & fix steps

EGR Volume Control Circuit / Position Sensor Low. LOGIC: The ECU detects an electrical fault in the EGR motor winding or the position sensor signal is out of range. ACTION: 1. Unplug EGR motor; check for corrosion in pins. 2. Check resistance of motor windings. 3. Check for carbon buildup jamming the valve open. FIX: Replace the EGR Valve assembly or repair the harness connector.

Red Seal field insights

Mitsubishi EGR valves are prone to "carbon jamming." You can sometimes clean them, but if the internal motor gear is stripped from fighting the carbon, the entire unit must be replaced.

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.

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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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