The Quick Diagnosis: Fault Code 301 on a Dingli JCPT means the platform load sensor is reading a weight above its rated capacity. This is likely caused by a failed or damaged load sensor cell, or it's genuinely overloaded.
Tools Required:
- Multimeter (with mV setting)
- 17mm socket and ratchet
- Torque wrench
- Laptop with Dingli diagnostic software (optional, but faster)
Safety Warning: Chock the wheels and disconnect the negative battery terminal. The machine may lurch if the brake solenoid de-energizes unexpectedly. This is a control system fault; do not attempt to bypass it to operate the lift.
Step-by-Step Fix
- Verify the Actual Load. The most obvious cause is the simplest. Remove all personnel, tools, and materials from the platform. Cycle the key. If the code clears, the machine was simply overloaded. Remind operators that the capacity is reduced when the deck extension is out.
- Inspect the Load Sensor Cell. The load sensor is a small, rectangular block of aluminum located under the platform, usually near the entry point. Inspect the sensor for physical damage. Look for cracks, dents from dropped tools, or corrosion. Check that the wiring harness connected to it is secure and hasn't been chafed or cut.
- Test Sensor Output Voltage. Reconnect the battery. With the platform empty, carefully back-probe the sensor's signal wire with your multimeter set to millivolts (mV). You are looking for a baseline voltage reading specified in the service manual (typically around 0.5 mV). If the reading is high (e.g., > 5.0 mV) or zero, the sensor has failed internally.
- Disconnect and Check Again. If the voltage is out of spec, disconnect the sensor's wiring harness. Check the platform controller (ECU) for the fault code again. If the code changes from 301 (Overload) to a new code related to an open circuit, you have confirmed the sensor itself is the problem. The ECU is correctly identifying a bad signal.
- Replace the Load Sensor. If the sensor is bad, unbolt the two 17mm mounting bolts holding it to the platform frame. Install the new sensor. Torque the bolts to the manufacturer's specification. Refer to your specific service manual for torque values—do not overtighten, as this can damage the new sensor cell. Reconnect the wiring harness.
- Calibrate the New Sensor. A new sensor requires calibration. This sets the "zero" point for an empty platform. This procedure typically requires the Dingli diagnostic software. Connect your laptop and follow the on-screen prompts in the calibration menu to set the zero-load value. Without this step, the machine will continue to throw the 301 code.
The Part You Need
The original issue is almost always a failed platform load sensor cell. The local dealer will tell you it's a 6-week wait for one from the factory, which means your machine is down for over a month.
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