Part 4 of 4: Error Codes and User Codes on Your 10-Year-Old 660SJ Boom Lift – Quick Fixes Before Calling a Tech

Last week in Part 3 we covered safety decals, paint, and appearance — the small details that keep you compliant. If you’re a roofer (or any contractor) who just bought one of these machines, now that your auction 660SJ is mechanically sound, freshly stickered, and looking sharp, let’s talk about the electronic side: error codes and user codes that pop up on the platform or ground controls.

On a 10-year-old AWP like the 660SJ, these codes are common. Most are simple to clear yourself and don’t require a full service call. Catching them early keeps the machine productive on the roof instead of sitting idle.

The must-have tool to read and clear error codes is the JLG Hand-Held Analyzer & Cable Kit.

Why Error Codes Show Up on Older Machines

After 10 years of jobsite use, wiring connections can loosen, sensors get dirty or misaligned, and control boards occasionally need a reset. The control system is designed to display a numbered code (or “FAULT” message) to help you diagnose the issue fast.

Most Common Codes and Quick Troubleshooting Steps

Key Switch Faulty — Code 212
Could be a damaged boom harness, faulty diode, bad connection, or faulty key switch.
Fix: Inspect the boom harness for damage. Check/replace the diode at the ground module. Replace the key switch if needed.
Foot Switch Faulty — Code 213
Could be a blown fuse, damaged foot switch harness, damaged boom harness, or faulty foot switch.
Fix: Check for a blown fuse near the ground module. Inspect both foot switch and boom harnesses for damage. Replace the foot switch if necessary.
Chassis Tilt Sensor Faults — Code 815
Could be incorrect tilt calibration, defective ground module, or faulty tilt sensor.
Fix: Recalibrate the tilt sensor. Check the ground module. Replace the external tilt sensor if needed.
Engine Related Codes (Low Oil Pressure) — Code 431
Could be contamination in the engine oil, low oil level, faulty oil pressure sensor, or faulty wiring.
Fix: Oil pressure should read 40–60 PSI at operating temperature. Confirm fluid levels are correct, check/replace the oil filter, inspect wiring for shorts, and replace the oil pressure sensor if required.

Pro tip: Many codes can be cleared by simply turning the key off for 30 seconds, then back on. If the code returns immediately, note the exact number and refer to the machine’s service manual.

OEM Resources from gciron.com

Full JLG Service Manual (covers complete fault code tables and troubleshooting for the 660SJ) → Shop JLG 660SJ Service Manuals & Diagnostic Guides here
JLG Hand-Held Analyzer & Cable Kit → Buy the JLG Analyzer Kit here

All genuine OEM electrical parts, sensors, and wiring harnesses are also stocked and ready to ship from www.gciron.com.

Bottom Line for Roofers

Error codes on a 10-year-old 660SJ are usually not a big deal — most are fixed in minutes with basic checks. Address them during your first annual inspection (already built into the budget from Part 1) and you’ll keep the machine running smoothly on every roofing job.

Wrapping Up the Series

You now have the complete roadmap to turn your auction 660SJ into a safe, reliable, and cost-effective tool for your roofing crew. Follow these steps and you’ll spend far less than renting a boom lift for every job.

Thanks for following along — now go put that boom lift to work. Safe roofing!

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