LGCM Fault Code
Free · no signupE12 / SPN 157 FMI 00
Loud Diesel Clatter / Pressure Limp
System
Fuel / HPCR
Symptom
Loud Diesel Clatter / Pressure Limp
Diagnosis & fix steps
LOGIC: Common Rail Pressure Exceeds Upper Limit (Overpressure).
ACTION: Inspect high-pressure pump Fuel Metering Unit (MeUn). Test coil resistance (spec: ~2.8–3.5Ω); remove valve and clean sliding spool of lacquer caused by poor-quality diesel fuel.
Red Seal field insights
Fuel Lacquer Sticking: Unfiltered or regional low-lubricity fuel leaves sticky varnish on the high-pressure pump metering valve spool, sticking it open and over-pressurizing the rail.
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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