Pothole Guard Deployment Failure Detected

Common Symptoms

• Platform LCD displays fault code 6056-14 after elevating the deck
• High-speed drive is blocked and machine will only creep at reduced speed
• Pothole guard flap visible hanging up or not fully extended to ground position
• Machine does not respond to full drive speed commands from platform controls
• Yellow or red fault indicator illuminates on the ground control panel
• Alarm sounds when operator attempts to drive at elevation
• Machine may allow slow creep movement but will not return to full drive speed

Probable Causes (Ranked by Likelihood)

• Pothole guard proximity sensor failed or out of adjustment, not confirming guard is in deployed position Very Likely
• Pothole guard mechanically jammed or obstructed by debris, mud, or bent hardware preventing full deployment Very Likely
• Wiring harness to pothole guard sensor chafed, unplugged, or corroded at the connector Likely
• Pothole guard actuator rod or linkage bent or broken, preventing guard from reaching deployed position Likely
• ADE controller not receiving a valid sensor signal due to a failed sensor or open circuit in the feedback loop Possible
• Platform elevation sensor triggering deployment check before guard mechanism fully travels to position Less Likely
• ADE controller software fault or corrupted calibration data for pothole guard circuit Less Likely

Step-by-Step Diagnostic Procedure

1. Lower the platform fully to ground and power the machine off. Visually inspect all four pothole guard flaps around the chassis perimeter. Each flap should hang freely and show no bent brackets, caked mud, or debris blocking travel.

2. With machine off, manually push each pothole guard flap through its full range of motion by hand. It should swing freely with light resistance. If any flap binds, sticks, or stops short, that is your mechanical fault. Clean out debris and straighten any bent linkage.

3. Locate the pothole guard proximity sensor on the chassis, typically mounted at the pivot bracket of each guard. Inspect the sensor body and the wiring connector. Look for crushed insulation, corrosion on the pins, or a connector that has pulled loose from road vibration.

4. With key ON and machine powered up, use a multimeter set to DC voltage. Probe the sensor signal wire against chassis ground. A healthy inductive proximity sensor typically outputs 0 V when the guard is not in range and switches to battery voltage (10-13 V on a 12 V system or 22-26 V on a 24 V system) when the target plate is within range. Confirm your reading matches the expected state for guard position.

5. Raise the platform slowly to the elevation threshold where deployment should trigger. Watch the guard flaps as the machine commands them to drop. If the flaps drop correctly but the fault still sets, the sensor is not detecting the guard in position. Recheck sensor gap. The gap between sensor face and the target tab is typically 2-5 mm. Loosen the sensor mount and adjust gap, then retest.

6. If sensor gap and wiring check out, connect to JLG Analyzer software via the data link at the ground controls. Navigate to the pothole guard input status in the I/O monitor. Confirm the ADE controller is reading the sensor input as active when the guard is physically deployed. A fault here with good wiring points to a failed sensor that needs replacement.

7. After any repair, clear the fault using JLG Analyzer software via the data link at the ground controls or the platform LCD active fault clear sequence, then cycle the machine through a full raise-and-drive test to confirm the fault does not return before returning the machine to service.

Frequently Asked Questions