Steer Angle Sensor Signal Out of Range
The JLG-6018-12 (ADE) diesel fault code means: Steer Angle Sensor Signal Out of Range. This is a serious severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $80-$350 DIY (sensor and connector repair parts). Pro shop labor typically $200-$600 depending on whether calibration, hydraulic inspection, or ADE diagnosis is required.
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Common Symptoms
- Platform LCD scrolls fault code 6018-12 and may display a steer fault message
- Drive function is limited or completely blocked from the ground or platform controls
- Steering feels unresponsive or machine tracks in one direction without input
- Yellow or red fault indicator is lit on the ground control panel
- Machine may allow boom functions but refuses to travel
- Alarm sounds when drive is attempted from either control station
- Steer angle indicator on the platform LCD shows an implausible or frozen value
Probable Causes (Ranked by Likelihood)
- Steer angle (feedback) sensor failed, out of calibration, or internally open/shorted Very Likely
- Damaged, corroded, or loose wiring harness connector at the steer feedback sensor Very Likely
- Sensor supply voltage out of spec due to a failing ADE controller output or blown fuse on the sensor supply circuit Likely
- Sensor shaft mechanically decoupled from the steer axle or linkage (broken pin, stripped spline, or loose mounting bracket) Likely
- ADE controller software requires steer calibration after sensor replacement or battery disconnect Possible
- Hydraulic steer cylinder binding or not reaching full stroke, causing sensor to read out of mechanical range Possible
- ADE controller input channel fault requiring controller replacement or reprogramming Less Likely
Step-by-Step Diagnostic Procedure
Start at the ground controls. Use the platform LCD to confirm 6018-12 is active and note whether any other steer or drive codes are stored alongside it. Scroll through active and stored faults using JLG Analyzer software via the data link at the ground controls if available.
Locate the steer angle (feedback) sensor, typically mounted at the steer axle pivot or on the steer cylinder on the axle. Visually inspect the sensor body for cracks, impact damage, and confirm the mounting bracket is tight and the sensor shaft is engaged with the linkage or actuator.
Inspect the sensor wiring harness from the sensor back toward the ADE controller. Look for chafed insulation, crushed conduit sections, and corroded or spread pins in the connector. Unplug the connector and clean pins with electrical contact cleaner before reconnecting.
With the key ON and system powered, measure DC voltage at the sensor connector supply pin against chassis ground. Most JLG steer feedback sensors expect a 5V reference supply. A reading below 4.75V or above 5.25V points to a wiring fault or failing ADE output. Confirm the ground pin shows less than 0.3V resistance drop back to chassis.
Measure the sensor signal output pin voltage at the connector (key ON, sensor connected). With the steer wheels centered, a typical potentiometer-type sensor should read near 2.5V DC (mid-scale). Rotate or manually move the steer linkage slightly if safe to do so and watch for the signal voltage to change smoothly. A fixed, pegged, or erratic reading confirms sensor failure.
Check the sensor supply fuse in the ADE fuse block. Consult the machine service manual for the specific fuse number for the steer feedback circuit. A blown fuse will drop the supply voltage to zero and set this code immediately.
If wiring and fuse check out and sensor output is erratic or dead, replace the steer angle sensor with the correct JLG part number for your model. After replacement, perform a steer calibration procedure using JLG Analyzer software via the data link at the ground controls or the EZcal calibration sequence from the platform LCD as described in the service manual. Skipping calibration after sensor replacement will likely leave the fault active.
If the code persists after a confirmed good sensor and successful calibration, inspect the steer cylinder for binding and verify full stroke is achievable. A cylinder that cannot reach mechanical stops can keep the sensor reading at an extreme value. Advanced hydraulic teardown or ADE controller diagnostics will be needed at that point.
Frequently Asked Questions
What does JLG fault code 6018-12 mean?
It means the ADE controller received a signal from the steer angle feedback sensor that was outside the expected voltage range. The controller cannot confirm where the steer wheels are pointed, so it limits or blocks drive to protect the machine and the operator.
Can the machine still be driven with code 6018-12 active?
Sometimes limited drive is still available at reduced speed, but on many configurations the ADE will block travel entirely until the fault is cleared. Do not attempt to drive the machine on a job site with an unknown steer position. Get the sensor circuit checked first.
How much does it cost to fix code 6018-12?
If it is a connector cleaning or minor wiring repair, parts are under $50 and a capable mechanic can do it on site. A replacement steer feedback sensor typically runs $80 to $200 in parts. If calibration with JLG Analyzer software or hydraulic cylinder work is needed, a shop visit will add $200 to $600 in labor.
Will the machine clear this code after I cycle the key?
The code will clear from active faults if the sensor signal returns to a valid range on the next key cycle. But if the sensor is truly failed or the wiring is damaged, the code will come right back as soon as the ADE reads the sensor. A cleared code with no repair is not a fix.