What is Komatsu PC210LC-8 Fault Code DHPAMA?

Fault Code DHPAMA on the Komatsu PC210LC-8 excavator indicates a hydraulic pump displacement control abnormality, specifically related to the main pump's swash plate angle sensor or control system malfunction. This code is triggered when the Electronic Control Module (ECM) detects that the hydraulic pump's displacement feedback signal doesn't match the commanded position or falls outside acceptable operational parameters.

This fault is critical for the PC210LC-8's performance because the variable displacement piston pumps are the heart of this excavator's hydraulic system. The swash plate angle directly controls hydraulic flow and pressure delivery to all work functions. When this control system malfunctions, the machine cannot properly modulate hydraulic power, severely impacting digging force, swing speed, and overall productivity. For used excavators, this code often appears due to sensor wear or contamination in the hydraulic control circuitry.

Common Symptoms

• Erratic or sluggish hydraulic performance across multiple functions, particularly noticeable during combined operations like swing-and-dig cycles
• Illuminated warning lamp on the instrument panel with reduced engine power (derate mode) to protect the hydraulic system
• Inconsistent response to joystick commands, with the machine seeming to "lag" or respond unpredictably
• Unusual pump noise or whining sounds from the main hydraulic pumps during operation
• Increased fuel consumption as the system struggles to maintain proper hydraulic pressure and flow

Potential Causes

The most common technical causes for DHPAMA on used PC210LC-8 excavators include:

• Faulty swash plate angle sensor (potentiometer-type sensor) due to internal wear, contamination, or electrical connection corrosion
• Damaged wiring harness between the pump displacement sensor and the ECM, particularly at flex points near the pump mounting area
• Hydraulic contamination causing the swash plate servo piston to stick or move erratically
• Worn pump regulator components, including the control spool valve or pilot solenoid valves
• ECM internal fault or corrupted calibration data affecting pump control algorithms
• Low hydraulic pilot pressure feeding the pump control circuit, often caused by clogged pilot filters

How to Troubleshoot and Fix Code DHPAMA

Step 1: Connect Diagnostic Software Use Komatsu KOMTRAX Plus or compatible diagnostic software to retrieve live data parameters. Monitor the pump displacement sensor voltage (typically 0.5-4.5V range) and compare the actual vs. commanded swash plate angles during operation. If readings fluctuate erratically or remain at extreme values, suspect sensor or wiring harness issues.

Step 2: Inspect Sensor and Electrical Connections Locate the displacement angle sensor on the main hydraulic pump (driver's side of engine). On used excavators, carefully inspect the connector pins for corrosion, bent terminals, or moisture intrusion. Check the wiring harness for chafing against the pump housing or engine block—a common wear point on PC210LC models. Use a digital multimeter to verify sensor resistance (typically 1-10kΩ depending on position) and check for proper 5V reference voltage supply from the ECM.

Step 3: Test Hydraulic Control Circuit Measure pilot pressure at the pump control port (should be 3.5-4.0 kg/cm²). Replace the pilot filter if it shows contamination. Manually check swash plate movement by disconnecting the servo piston and ensuring free movement without binding. For used machines, drain a hydraulic sample to check for metal particles indicating internal pump wear.

Step 4: Component Replacement or ECM Reset If sensor values are out of specification, replace the swash plate angle sensor (Komatsu part number specific to PC210LC-8). After replacement, perform an ECM calibration using diagnostic software to relearn pump characteristics. If all physical components test correctly, the issue may require ECM reprogramming or replacement.

---

Disclaimer: This guide provides general troubleshooting information. Always consult the official Komatsu PC210LC-8 service manual and consider professional diagnostic services for complex hydraulic system repairs. Improper repairs can cause catastrophic pump failure or safety hazards.