What is Hitachi ZX170W-3 Fault Code P1345(636-7)?

Fault Code P1345(636-7) on the Hitachi ZX170W-3 wheeled excavator indicates a camshaft position sensor (CMP) circuit malfunction or timing correlation error between the camshaft and crankshaft position sensors. This diagnostic trouble code (DTC) is triggered when the Engine Control Module (ECM) detects that the camshaft position signal is out of synchronization with the crankshaft position signal, typically beyond the acceptable threshold of ±5 degrees.

This code is critical for the Isuzu engine used in the ZX170W-3 because precise camshaft-to-crankshaft timing correlation is essential for proper fuel injection timing, ignition sequencing, and overall engine performance. When this synchronization fails, the ECM cannot accurately determine piston position, leading to potential engine performance issues and emissions problems.

Common Symptoms

• Check Engine Light (CEL) or malfunction indicator lamp illuminated on the instrument panel
• Engine derate mode activated, limiting maximum RPM to approximately 1500-2000 RPM to protect the engine
• Hard starting or extended cranking time, especially when the engine is cold
• Rough idle or unstable engine operation at low RPM with noticeable vibration
• Reduced hydraulic performance due to limited engine power output affecting pump operation

Potential Causes

The most common causes for fault code P1345 on used ZX170W-3 excavators include:

• Worn or failed camshaft position sensor due to heat exposure and age-related deterioration common in machines with 5,000+ operating hours
• Damaged or corroded wiring harness at known rub points near the engine block where vibration causes insulation wear
• Timing chain/belt stretch or improper timing component installation during previous maintenance
• Faulty crankshaft position sensor providing incorrect reference signals to the ECM
• ECM software corruption or calibration issues, particularly in older machines that haven't received manufacturer updates
• Loose or corroded electrical connectors at the CMP sensor due to exposure to engine heat and environmental contamination

How to Troubleshoot and Fix Code P1345(636-7)

Step 1: Visual Inspection and Data Retrieval Connect a diagnostic scanner compatible with Hitachi/Isuzu protocols (such as Dr.ZX or equivalent) to retrieve freeze frame data showing engine conditions when the fault occurred. Inspect the camshaft position sensor connector for corrosion, bent pins, or moisture intrusion—common issues on used machines. Check the wiring harness routing for signs of rubbing against engine components or heat shields.

Step 2: Electrical Testing Using a digital multimeter (DMM), test the CMP sensor resistance with the connector disconnected. Typical specifications should read between 500-2000 ohms at room temperature (consult service manual for exact values). Test the supply voltage from the ECM to the sensor (should be approximately 5V reference voltage). Check ground circuit continuity with less than 5 ohms resistance to chassis ground.

Step 3: Mechanical Timing Verification Before replacing sensors on used excavators, verify mechanical timing alignment using the timing marks on the crankshaft pulley and camshaft gear. If the machine has recently undergone timing component service, misalignment is a likely culprit. Inspect the timing chain tension and check for excessive slack indicating wear.

Step 4: Sensor Replacement and Calibration If electrical testing confirms sensor failure, replace the camshaft position sensor with a genuine Hitachi or OEM-equivalent part (Part # varies by engine serial number). After installation, clear the fault codes and perform an ECM relearn procedure using diagnostic software to establish new baseline parameters. On high-hour used machines, consider replacing both camshaft and crankshaft position sensors simultaneously to prevent repeat failures.

For used excavators specifically: Always inspect connector seals and apply dielectric grease to prevent moisture-related failures. Check that previous repairs haven't created new harness rub points.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Hitachi service manual for your specific machine serial number and consider professional diagnostic assistance for complex electrical issues. Improper repairs may void warranties or create safety hazards.