Caterpillar Fault Code
Free · no signupE1239
Heavy Lift Solenoid: Current Above Normal
Variant 1
System
Hydraulic
Symptom
Heavy Lift Solenoid: Current Above Normal
Diagnosis & fix steps
LOGIC: Short to ground or shorted coil.
ACTION: Unplug solenoid; if code changes to "Current Below Normal," replace solenoid.
Red Seal field insights
Voltage: On a CAT 336, this is a 24V PWM signal from the ECM. Check harness for rubbing near the valve bank.
Variant 2
System
Aftertreatment
Symptom
100% Derate / Forced Idle
Diagnosis & fix steps
LOGIC: DPF #1 Conditions Not Met for Active Regen.
ACTION: Check Soot Load level. Perform a "Manual DPF Regeneration" via CAT ET.
Red Seal field insights
Logic: Operator ignored too many regen requests.
PRO-TIP: Check for intake leaks; high soot can be caused by a "rich" burn.
Variant 3
System
Hydraulic
Symptom
Heavy Lift Weak / No Response
Diagnosis & fix steps
LOGIC: Heavy Lift Solenoid Valve: Current Above Normal.
ACTION: Unplug the solenoid and check internal coil resistance. If resistance is near 0 ohms, the coil is shorted internally.
Red Seal field insights
Physics: High current means low resistance. A shorted coil will pull down the ECM supply voltage and can damage the driver circuit.
Track this across your whole fleet
This code is free to read. AM Fleet Integrity lets your team log fault codes against assets, plus the full fault-code library, QR operator reporting, PM scheduling and predictive alerts. Start free — no credit card required.
Start your free trial