What is Kato Excavator Fault Code P0335?

Fault Code P0335 indicates a Crankshaft Position Sensor "A" Circuit Malfunction. This diagnostic trouble code (DTC) means the Engine Control Module (ECM) has detected an irregular, intermittent, or absent signal from the crankshaft position sensor (CKP sensor).

In Kato excavators, this sensor is critical for monitoring engine speed and crankshaft positioning. The ECM relies on this data to precisely control fuel injection timing, ignition timing (if applicable), and overall engine synchronization. When the CKP sensor signal fails or becomes erratic, the ECM cannot accurately determine piston position, which severely impacts engine performance and can trigger protective shutdown modes to prevent internal damage.

Common Symptoms

When P0335 is active on your Kato excavator, operators typically experience:

• Engine cranks but fails to start or experiences extremely difficult starting conditions
• Sudden engine stalling during operation, often without warning
• Check Engine Light (CEL) or malfunction indicator lamp illuminated on the dashboard
• Rough idling with noticeable misfires or inconsistent RPM fluctuations
• Loss of power or the engine entering a derate/limp mode with significantly reduced performance

Potential Causes

Several factors can trigger P0335 on used Kato excavators:

• Failed or failing crankshaft position sensor due to heat exposure, vibration damage, or internal component breakdown
• Damaged sensor wiring harness from rubbing against engine components, particularly near the bellhousing area where movement and heat are constant
• Corroded or loose electrical connectors at the sensor or ECM connection points—common in machines exposed to moisture or harsh environments
• Worn or damaged reluctor ring (tone wheel) on the crankshaft with missing teeth or debris buildup
• ECM internal faults or software corruption (less common but possible in older machines)
• Incorrect sensor air gap due to improper installation or engine wear shifting component positions

How to Troubleshoot and Fix Code P0335

Step 1: Visual Inspection Begin by locating the crankshaft position sensor, typically mounted near the crankshaft pulley or flywheel housing. Inspect the sensor body for physical damage, oil contamination, or excessive heat discoloration. On used excavators, carefully examine the wiring harness for fraying, abrasion points where it contacts metal surfaces, or signs of previous repairs with electrical tape.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor connector and measure resistance across the sensor terminals (typically 200-1000 ohms depending on specifications—consult your Kato service manual). Check for continuity in the wiring from sensor to ECM, and inspect for short circuits to ground. Examine all connector pins for corrosion, bent terminals, or moisture intrusion—a frequent issue in older machines.

Step 3: Sensor Air Gap and Reluctor Ring Inspection Verify the air gap between the CKP sensor tip and the reluctor ring meets manufacturer specifications (usually 0.5-1.5mm). Rotate the engine manually to inspect the entire reluctor ring for missing teeth, cracks, or metal debris accumulation that could disrupt the magnetic field.

Step 4: Component Replacement and Verification If testing confirms sensor failure, replace with an OEM or high-quality aftermarket CKP sensor. After installation, clear fault codes using diagnostic software compatible with Kato systems and perform a test run. Monitor live data to confirm the ECM receives consistent crankshaft position signals at various RPM levels.

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Disclaimer: This guide provides general diagnostic information. Always consult your Kato service manual and consider professional diagnostic services, especially for complex electrical issues or if you're unfamiliar with ECM systems.