Case CX210C Fault Code P0335: Complete Diagnostic Guide

What is Case CX210C 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), which is critical for monitoring engine speed and crankshaft angle.

The CKP sensor generates a signal that tells the ECM the exact position and rotational speed of the crankshaft. This information is essential for controlling fuel injection timing, ignition timing (if applicable), and overall engine synchronization. On the Case CX210C excavator, this sensor directly impacts the performance of the Isuzu 4HK1X diesel engine. Without accurate crankshaft position data, the engine cannot run efficiently—or may not start at all. This code is particularly common in used excavators due to sensor wear, harness damage, or connector corrosion from years of exposure to vibration and harsh jobsite conditions.

Common Symptoms

When P0335 is active on your Case CX210C, you may experience:

• Engine cranks but fails to start or experiences extended cranking before starting
• Rough idling, misfiring, or stalling during operation
• Check Engine Light (CEL) or malfunction indicator lamp illuminated on the dashboard
• Loss of power or engine hesitation under load during digging or lifting operations
• Engine RPM gauge reading erratically or showing zero while engine runs

Potential Causes

The most common technical reasons for P0335 on used Case CX210C excavators include:

• Failed crankshaft position sensor due to heat exposure or internal component degradation
• Damaged or frayed wiring harness, especially near the sensor mounting location where vibration causes wire chafing
• Corroded or loose electrical connectors at the sensor or ECM—common in machines with high hours
• Broken or missing reluctor ring teeth on the crankshaft (rare but possible after severe engine damage)
• ECM internal faults or software corruption (less common)
• Improper sensor air gap caused by incorrect installation or mounting bracket damage
• Oil contamination on the sensor tip affecting magnetic field detection

How to Troubleshoot and Fix Code P0335

Step 1: Visual Inspection Begin by locating the crankshaft position sensor on the engine block near the flywheel housing. Inspect the wiring harness for visible damage, abrasion, or signs of rubbing against engine components—common wear points on used excavators. Check the electrical connector for corrosion, bent pins, or moisture intrusion. Clean connections with electrical contact cleaner if necessary.

Step 2: Test Sensor Resistance Disconnect the CKP sensor connector and use a digital multimeter to measure resistance across the sensor terminals. Typical resistance values range from 500 to 1,500 ohms (consult your Case service manual for exact specifications). A reading outside this range indicates a faulty sensor requiring replacement.

Step 3: Check Signal Output With the sensor connected, use a multimeter set to AC voltage and crank the engine. You should see a fluctuating AC voltage signal (typically 0.3 to 1.0 volts). No signal indicates sensor failure or wiring issues between the sensor and ECM.

Step 4: Verify Wiring Continuity Test continuity between the sensor connector and the ECM connector using a wiring diagram. Check for open circuits or short circuits to ground. Pay special attention to harness routing near hot exhaust components or sharp edges where insulation may have degraded on older machines.

Step 5: Inspect Air Gap and Reluctor Ring Remove the sensor and verify the air gap between the sensor tip and reluctor ring (typically 0.5-1.5mm). Use a feeler gauge if replacement is necessary. Visually inspect the reluctor ring teeth for damage or missing segments—though uncommon, this occurs in high-hour used equipment.

Step 6: Use Diagnostic Software Connect Case diagnostic software or a compatible J1939 scanner to clear codes and monitor live data. Observe crankshaft position sensor signal while cranking. Erratic or absent data confirms sensor circuit failure.

For used excavators, always check for previous repair attempts, aftermarket sensors of poor quality, or improperly routed harnesses before replacing components. Replace the sensor with an OEM Case/Isuzu part for reliability.

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Disclaimer: This guide provides general diagnostic information. Always consult your Case CX210C service manual and consider professional evaluation for complex electrical issues or if you're unfamiliar with excavator systems.