Sany Excavator Fault Code P345: Complete Diagnostic Guide

What is Sany Excavator Fault Code P345?

Fault Code P345 indicates a Fuel Injection Pressure Sensor Circuit malfunction in Sany excavators. This code triggers when the Electronic Control Module (ECM) detects voltage readings outside the normal operating range (typically 0.5-4.5V) from the rail pressure sensor on the common rail fuel system.

This sensor is critical for Sany's diesel fuel delivery system, as it continuously monitors high-pressure fuel delivered to the injectors. The ECM relies on this data to adjust injection timing and fuel volume for optimal combustion. When P345 activates, the machine may enter derate mode to prevent engine damage from improper fuel pressurization, significantly impacting jobsite productivity.

Common Symptoms

When Code P345 is active, operators typically experience:

• Engine derate limiting maximum RPM to 1500-1800, reducing hydraulic power
• Check Engine Light or warning icon illuminated on the instrument cluster
• Hard starting or extended cranking time, especially in cold conditions
• Rough idling with noticeable RPM fluctuations at low throttle
• Black smoke from exhaust due to improper fuel atomization

Potential Causes

Several factors trigger P345 on used Sany excavators:

• Damaged fuel pressure sensor due to heat stress or internal failure (common after 5,000+ hours)
• Corroded or loose electrical connectors at the sensor harness—a known issue where the connector sits near the engine block
• Wiring harness chafing against the fuel rail or heat shield, causing shorts or open circuits
• Failed ECM power supply to the sensor circuit (5V reference voltage)
• Contaminated fuel causing sensor membrane degradation
• Previous repairs using non-OEM sensors with incorrect voltage output curves

How to Troubleshoot and Fix Code P345

Step 1: Preliminary Inspection Visually inspect the fuel rail pressure sensor (typically mounted on the high-pressure fuel rail near cylinder #1). Check the wiring harness for abrasion, heat damage, or oil contamination. On used excavators, examine connector pins for corrosion or bent terminals—spray with electrical cleaner and ensure tight connection.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor and measure the reference voltage from the ECM at the harness connector (should read 4.5-5.2V with ignition on). Test sensor resistance across terminals (typically 100-300 ohms depending on Sany model). Check for short to ground by measuring continuity between sensor wires and chassis.

Step 3: Live Data Analysis Connect Sany diagnostic software (PC Suite or compatible scan tool) to monitor real-time fuel pressure sensor voltage. At idle, readings should fluctuate between 0.8-1.5V (approximately 200-400 bar). If voltage is stuck at 0V, 5V, or fluctuating erratically, replace the pressure sensor.

Step 4: Post-Repair Verification After replacing faulty components, clear codes and perform a fuel system prime procedure. Test under load to ensure the sensor accurately tracks pressure changes during throttle application.

Disclaimer: This guide provides general troubleshooting steps. Always consult Sany service manuals and consider professional diagnostic services for complex fuel system issues on high-value equipment.