Decoding the Chevy Silverado P0335 Code: What You Need to Know
Ever wondered about that persistent check engine light? When it stays illuminated, it often indicates a specific issue that needs attention. One common culprit is the P0335 code, which signifies a problem with the Crankshaft Position Sensor “A” Circuit. This sensor plays a crucial role in engine management, and its malfunction can lead to serious drivability issues.
What Does the P0335 Code Signify in a Chevy Silverado?
The P0335 code is a generic OBD-II trouble code indicating that the vehicle’s Engine Control Module (ECM) has detected a malfunction in the Crankshaft Position Sensor Circuit. Specifically, it signals that the ECM isn’t receiving a valid signal from the sensor for at least 8 seconds. This issue might stem from a faulty sensor, damaged wiring, or problems within the ECM itself.
The Crankshaft Position Sensor (CKP) is typically situated behind the starter in the rear section of the engine block. It consists of a B+ power supply, a ground, and a signal circuit. The sensor communicates with a 24X reluctor wheel attached to the crankshaft. As the crankshaft rotates, the teeth on the reluctor wheel pass through the sensor’s magnetic field, generating a signal that the PCM (Powertrain Control Module) uses to determine engine speed and position.
Implications and Symptoms of the P0335 Code
When this code appears, you might notice several signs indicating engine issues:
- The check engine light (CEL) illuminating on the dashboard.
- Engine struggles to start or fails to start altogether.
- Rough idle or irregular engine performance.
- Engine stalls unexpectedly or runs sluggishly.
- Unusual fluctuations in engine RPM, often oscillating between 500 and 1000 RPM.
- Fuel injectors may become inactive or malfunction.
Common Causes Behind the P0335 Error
Understanding the root causes helps in effective troubleshooting. Typical reasons include:
- Worn or damaged wiring harnesses connected to the crankshaft sensor.
- Physical damage or misalignment of the reluctor wheel attached to the crankshaft.
- Defective or faulty crankshaft position sensor itself.
- Corrosion or poor electrical connections at the sensor or wiring.
- Issues with the Engine Control Module (ECM).
- Excessive crankshaft end play, leading to misalignment of the sensor and reluctor wheel.
- Engine running out of fuel or other mechanical failures affecting sensor operation.
Steps to Reproduce and Diagnose the P0335 Code
To accurately diagnose this issue, follow these steps:
- Review Freeze Frame data to identify under what conditions the code was set.
- Attempt to replicate the driving conditions when the code originally appeared.
- Use diagnostic tools like a multimeter or oscilloscope to check sensor signals.
- Inspect wiring harnesses and connectors for damage, corrosion, or loose connections.
- Physically examine the reluctor wheel for cracks or debris.
- If necessary, clear the code and test drive to see if it reoccurs under similar conditions.
Effective Solutions for the P0335 Error in a Chevy Silverado
1. Inspect and Replace the Crankshaft Position Sensor
Begin by visually inspecting the sensor for signs of wear, damage, or contamination. The sensor is resistive and includes internal circuitry like a Hall effect. If the sensor appears compromised, replacing it is recommended. Here’s how:
- Disconnect the negative terminal of the battery for safety.
- Remove the starter motor by unbolting it carefully.
- Apply a penetrating lubricant around the sensor area to loosen debris or corrosion.
- Remove the faulty sensor.
- Install a new, high-quality sensor such as those from AC Delco, ensuring proper alignment and connection.
For detailed guidance, refer to instructional videos or repair manuals specific to your Silverado model.
2. Examine and Repair Wiring and Connectors
If the sensor looks intact, check the wiring harness for damage. Look for frays, cuts, or corrosion. Use a multimeter to verify continuity and resistance between the sensor and the ECM. Replace damaged wires or connectors as needed. Ensure all connections are secure and free of debris.
3. Check and Test the ECM (Engine Control Module)
If wiring and sensor are in good condition, the ECM might be at fault. Testing involves measuring resistance across the sensor circuit at the ECM connector. If anomalies are found, the ECM might need replacement or reprogramming, which is best handled by professionals.
4. Inspect and Replace Fuses and Ground Connections
Verify the integrity of related fuses, such as F46UA, and ensure all ground points, including the engine ground, are secure and free of corrosion. A poor ground connection can lead to false readings or sensor malfunctions.
Additional Tips
- Ensure the engine and drive unit case are clean and properly grounded.
- Check for proper installation of the propeller shaft to prevent excessive crankshaft end play.
- Utilize diagnostic tools like the Connector Test Adapter Kit J 35616-A for precise testing.
Cost Considerations for Repairing the P0335 Code
The cost to fix this issue varies depending on the diagnosis. Replacing the crankshaft position sensor is generally affordable, ranging from $35 to $80 for parts. If performed DIY, labor costs are eliminated. However, professional repair services might charge between $150 and $250, including parts and labor, especially if ECM replacement or complex wiring repairs are necessary.
Driving with the P0335 Code: Is It Safe?
It is strongly advised not to drive your Silverado if this code appears. The engine may stall unexpectedly, which can be dangerous, particularly on busy roads or highways. Continuing to drive can cause further damage to engine components or pose safety risks. Always prioritize professional diagnosis and repair before resuming normal driving.
Frequently Asked Questions (FAQs)
Where is the camshaft position sensor located on a 2002 Silverado?
The camshaft position sensor is situated at the rear of the engine, behind the intake manifold. It connects via a three-wire connector for accurate positioning signals.
How is camshaft timing performed?
Camshaft timing involves locking the camshaft gear in alignment with the crankshaft, ensuring the timing dots on the gears are perfectly aligned. This process guarantees proper synchronization of engine valves and pistons.
What role does the Crankshaft Sensor play in the Silverado?
The crankshaft sensor produces a variable-frequency DC voltage signal, with approximately 58 pulses per rotation. It detects the passing teeth of the reluctor wheel, providing critical data to the ECM to calculate engine speed and position, essential for ignition and fuel injection timing.