Caterpillar Fault Code
Free · no signup1657-4
Left Joystick Thumbwheel: Voltage Below Normal
Variant 1
System
Controls
Symptom
Left Joystick Thumbwheel: Voltage Below Normal
Diagnosis & fix steps
LOGIC: Short to ground on the 5V reference or signal wire.
ACTION: Inspect wiring inside the joystick pod for pinching.
Red Seal field insights
Thumbwheels are high-use; the internal pivot often wears through the wire insulation.
Variant 2
System
Controls
Symptom
Left Tool Inop
Diagnosis & fix steps
LOGIC: Left Joystick Thumbwheel Voltage Below Normal.
ACTION: Inspect the 8V supply circuit. Check for broken wires at the base of the joystick handle.
Red Seal field insights
Logic: Short to ground in the PWM signal or supply wire.
PRO-TIP: Repetitive motion often cracks wires inside the joystick boot.
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