Why does the excavator switch to degraded mode?

When a fault occurs in the pressure sensors (English: pressure pick off), the machine's controller limits the power and speed of working movements (e.g., arm, bucket, or rotation). This action aims to protect hydraulic pumps, distributors, and the engine from permanent damage. The machine becomes noticeably slower and weaker.

List of Pressure Sensor System Errors (E150 - E166)

The following errors indicate problems with specific pressure transducers/sensors in individual hydraulic systems:

• E150, E151: Error in the pressure sensor of the arm B159.
• E153, E154: Error in the lifting/boom pressure sensor B160.
• E156, E157: Error in the left rotation mechanism pressure sensor B167.
• E159, E160: Error in the travel/translation pressure sensor B162.
• E162, E163: Error in the bucket pressure sensor B163.
• E165, E166: Error in the right rotation mechanism pressure sensor B168.

Step-by-step instructions - What to do after an error occurs?

When one of the above codes appears on the control panel and the machine switches to degraded mode, follow the safety procedure below:

1. Turn off the engine: Do not continue working "forcefully". Further operation of the excavator with incorrect pressure readings may lead to overload and seizure of key hydraulic components.
2. Check the condition of the wires and their mounting: Often, the fault does not lie in the sensor itself, but in a damaged electrical harness. Locate the appropriate sensor and check if the cables are frayed, torn, or oxidized at the connectors. Pay attention to the stability of the wire mounting.
3. Locate leaks and carry out repairs: Inspect the area around the sensor and the hydraulic hoses of the system for oil leaks. A drop in pressure in the system or the presence of a leak directly affects readings and generates system errors.

Need support? Rely on professional WIBAKO service

If inspecting the electrical harness did not provide a solution, and the fault persists, detailed computer diagnostics, sensor replacement, or regeneration of hydraulic components may be necessary.

At WIBAKO, we have been specializing in the repair and service of construction machinery (including Liebherr, Caterpillar, Volvo, Komatsu) for years. We have our own diagnostic facilities, specialized hydraulic teams, and a rich inventory of new and used spare parts.