Sany Excavator Fault Code H315: Complete Diagnostic Guide

What is Sany Fault Code H315?

Sany Fault Code H315 indicates a malfunction in the hydraulic pump pressure sensor circuit or an abnormal pressure reading detected by the Engine Control Module (ECM). This code specifically monitors the main hydraulic pump's pressure feedback signal, which is critical for engine load management and preventing over-pressurization.

In Sany excavators, the ECM continuously monitors hydraulic system pressure to optimize engine performance and protect components from damage. When the pressure sensor delivers erratic signals, falls outside normal parameters (typically 0-400 bar), or experiences circuit faults, Code H315 triggers. This is particularly critical because improper pressure readings can lead to reduced digging force, engine derate conditions, or even catastrophic pump failure if left unaddressed.

Common Symptoms

When Code H315 is active, operators typically experience:

• Engine warning light or hydraulic system malfunction indicator illuminated on the dashboard
• Reduced hydraulic power or sluggish boom/arm/bucket movements during operation
• Engine derate mode engaging unexpectedly, limiting RPM to protect the system
• Intermittent loss of auxiliary hydraulic functions (breaker, grapple, or quick coupler operations)
• Erratic engine response when demanding high hydraulic flow under heavy loads

Potential Causes

The most common technical causes for Code H315 on used Sany excavators include:

• Failed hydraulic pressure sensor due to internal component degradation or contaminated hydraulic fluid exposure
• Damaged wiring harness near the main pump area where cables rub against the rotating assembly or frame
• Corroded connector pins at the sensor plug, especially on machines operating in wet or coastal environments
• ECM software calibration drift in older units requiring parameter updates
• Contaminated hydraulic oil causing sensor membrane failure or blockage
• Worn pump components creating actual pressure anomalies the sensor correctly reports

How to Troubleshoot and Fix Code H315

Step 1: Visual Inspection Begin by locating the main hydraulic pump pressure sensor (typically mounted on the pump housing). Inspect the wiring harness for abrasion, cuts, or evidence of rubbing against moving parts—common on used excavators with 3,000+ hours. Check the connector for corrosion, oil contamination, or bent pins.

Step 2: Electrical Testing Using a digital multimeter, perform a continuity test on the sensor circuit with the ignition off. Sany sensors typically operate on a 5-volt reference signal. Check for:

• Supply voltage: Should read 4.5-5.2V at the sensor connector
• Ground integrity: Less than 0.5 ohms resistance to chassis ground
• Signal wire: Should show variable resistance (typically 500-4500 ohms) corresponding to pressure changes

Step 3: Sensor Functionality Test With the engine running at idle, monitor the live sensor output using Sany diagnostic software or a compatible OBD scanner. The pressure reading should stabilize between 20-50 bar at idle and increase proportionally when operating hydraulic functions. Erratic readings or fixed values indicate sensor failure.

Step 4: Component Replacement Protocol If sensor replacement is needed, always replace the O-ring seal and torque to manufacturer specifications (typically 25-30 Nm). For used excavators, consider replacing the entire sensor harness section if wiring shows any wear, as intermittent faults will recur. After installation, clear codes and perform a complete operational test cycle.

Step 5: Hydraulic System Verification Check hydraulic oil condition and contamination levels. Replace filters and oil if the system hasn't been serviced per OEM intervals, as sensor contamination often stems from degraded fluid in older machines.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Sany service manual for your specific excavator model and serial number. Complex hydraulic or electrical issues should be diagnosed by certified technicians with proper diagnostic equipment to prevent further damage or safety hazards.