Sumitomo SH210-6 Fault Code 602: Complete Diagnostic Guide

What is Sumitomo SH210-6 Fault Code 602?

Fault Code 602 on the Sumitomo SH210-6 excavator indicates a hydraulic pump flow control system malfunction, specifically related to the main pump delivery pressure sensor circuit or regulator control valve issue. This code is triggered when the Electronic Control Module (ECM) detects an abnormal signal from the pressure sensor monitoring the main hydraulic pump's output, or when the pump's flow control solenoid fails to respond correctly.

This fault is critical for the SH210-6 because the hydraulic pump is the heart of all machine functions. The pressure sensor provides real-time feedback to the ECM, which then adjusts pump displacement and flow to match operational demands. When this system malfunctions, the excavator cannot properly regulate hydraulic power, leading to reduced performance and potential component damage.

Common Symptoms

• Sudden loss of hydraulic power across all functions (boom, arm, bucket, and swing operations become sluggish)
• Warning lamp illumination on the instrument panel, often accompanied by an audible alarm
• Erratic hydraulic response where the machine alternates between normal and reduced power output
• Engine overspeed or hunting as the ECM struggles to match engine RPM with hydraulic load demands
• Complete shutdown of auxiliary hydraulic functions while travel motors may continue operating

Potential Causes

The most common technical causes for Code 602 on used SH210-6 excavators include:

• Faulty main pump pressure sensor – These sensors deteriorate over time, especially in machines with 5,000+ operating hours, producing intermittent or incorrect voltage signals
• Damaged wiring harness at the pump mounting area where vibration and heat cause insulation breakdown and wire chafing
• Corroded electrical connectors on the pressure sensor or flow control solenoid, particularly common in excavators operated in wet or coastal environments
• Failed pump regulator solenoid valve that controls pump displacement angle
• Contaminated hydraulic oil causing the pressure sensor port to become blocked or providing false readings
• ECM software glitches or internal ECM failure, though less common than sensor/wiring issues

How to Troubleshoot and Fix Code 602

Step 1: Initial Inspection and Code Verification Connect a diagnostic scanner compatible with Sumitomo systems (or generic CANbus reader) to verify Code 602 is active and check for additional stored codes. Record all parameters, especially hydraulic pressure readings and sensor voltage outputs (should typically read 0.5-4.5V depending on pressure).

Step 2: Visual and Physical Inspection Inspect the main pump pressure sensor (located on the main hydraulic pump body) and its wiring harness for obvious damage. On used excavators, pay special attention to connector corrosion – disconnect the sensor connector and check for green oxidation or moisture. Inspect the harness routing from the pump to the ECM for wear points where cables contact the frame or pump housing.

Step 3: Electrical Testing Using a digital multimeter, perform voltage and resistance checks:

• Test sensor output voltage with ignition ON, engine OFF (should show reference voltage around 5V)
• Check sensor ground continuity (should be less than 1 ohm resistance to chassis ground)
• Measure solenoid resistance at the pump regulator (typically 10-30 ohms; consult service manual for exact specification)

Step 4: Sensor and Component Testing If electrical tests pass, the pressure sensor itself may be faulty. Before replacement, check if the sensor port is blocked by debris – remove the sensor and inspect the threaded port. Clean with brake cleaner if contaminated. For used machines, consider replacing both the sensor and connector pigtail simultaneously, as aged connectors often cause repeat failures.

Step 5: Hydraulic System Checks Verify hydraulic oil quality and check for metal contamination that might indicate pump wear. Test actual pump pressure using a mechanical pressure gauge at the test port (should achieve 320-350 bar/4,600-5,000 PSI at relief). If mechanical pressure is correct but Code 602 persists, replace the pressure sensor.

Disclaimer: This guide provides general troubleshooting information for experienced technicians. Always consult the official Sumitomo service manual for your specific machine serial number. If unfamiliar with high-pressure hydraulic systems or electrical diagnostics, seek assistance from a certified Sumitomo technician to avoid injury or equipment damage.