The Diagnostic Trouble Code (DTC) P0335 indicates a “Crankshaft Position Sensor A Circuit Malfunction”. This code is triggered when your vehicle’s Powertrain Control Module (PCM) detects an issue within the crankshaft position (CKP) sensor circuit. Understanding this code is crucial for diagnosing engine performance problems, starting issues, and even potential breakdowns. As a vital component in modern vehicles, the crankshaft position sensor plays a key role in engine management. Let’s delve into the specifics of the P0335 code, exploring its function, symptoms, potential causes, and how to diagnose and fix it.
What is a Crankshaft Position Sensor?
The Crankshaft Position Sensor (CKP sensor), often simply called the crankshaft sensor, is an essential part of your car’s engine management system. Its primary function is to monitor the speed and position of the crankshaft as it rotates. This information is relayed to the PCM, which uses it for several critical engine operations:
- Ignition Timing: The PCM needs to know the crankshaft’s position to accurately time the firing of the spark plugs, ensuring optimal combustion.
- Fuel Injector Timing: Similarly, the CKP sensor signal is used to synchronize the fuel injectors, delivering fuel at the precise moment for efficient engine operation.
- Misfire Detection: By monitoring the crankshaft’s rotation, the PCM can detect irregularities that indicate engine misfires.
- Engine Speed (RPM): The CKP sensor is a primary source for determining engine speed, displayed on your tachometer.
The CKP sensor typically works in conjunction with a reluctor wheel, a toothed disc attached to the crankshaft. As the crankshaft rotates, the teeth of the reluctor wheel pass by the sensor, generating an AC voltage signal. The frequency and amplitude of this signal vary with the crankshaft’s speed and position. The PCM interprets these signals to understand the crankshaft’s dynamics. A fault in this system, such as a circuit malfunction, will lead to the P0335 code.
Symptoms of a P0335 Code
When the PCM detects a P0335 code, you may experience a range of symptoms affecting your vehicle’s performance. These can vary in severity, but it’s important to address them promptly to prevent further issues. Common symptoms include:
- Check Engine Light: The most immediate sign is the illumination of the Malfunction Indicator Lamp (MIL), commonly known as the “Check Engine Light,” on your dashboard.
- Engine Stalling or Hesitation: A faulty CKP sensor signal can disrupt the engine’s timing, leading to stalling, especially at idle, or hesitation during acceleration.
- Hard Starting or No Starting Condition: In some cases, a malfunctioning CKP sensor can prevent the engine from starting altogether, as the PCM may not be able to determine the crankshaft position for ignition and fuel injection.
- Rough Idling: An erratic crankshaft signal can cause the engine to idle roughly or unevenly.
- Reduced Engine Power: The PCM may limit engine power to protect the engine when a CKP sensor issue is detected, resulting in decreased acceleration and overall performance.
- Misfires: As the CKP sensor is involved in misfire detection, a circuit malfunction can also lead to actual engine misfires, causing rough running and potential engine damage if left unaddressed.
- Poor Fuel Economy: Inefficient combustion due to timing issues can result in decreased fuel efficiency.
It’s important to note that these symptoms can also be associated with other engine problems. Therefore, a proper diagnosis is crucial to pinpoint the exact cause and address it effectively.
Potential Causes of DTC P0335
The P0335 code indicates a “circuit malfunction,” meaning the problem lies within the electrical circuit of the crankshaft position sensor. Several factors can contribute to this, including:
- Faulty Crankshaft Position Sensor: The sensor itself may be defective due to wear, damage, or internal failure.
- Wiring Issues: Damage to the wiring harness connecting the CKP sensor to the PCM is a common cause. This can include:
- Loose or Corroded Connectors: Connections at the sensor or PCM may be loose, corroded, or damaged, disrupting the electrical signal.
- Damaged Wires: Wires can be frayed, broken, or shorted due to environmental exposure, engine heat, or physical damage.
- Reluctor Wheel Damage: Although less common for a “circuit malfunction” code, damage to the reluctor wheel can indirectly affect the sensor signal. If the reluctor wheel is bent, damaged, or has missing teeth, it can cause erratic signals that the PCM might interpret as a circuit issue.
- Incorrect Sensor Installation: If the CKP sensor was recently replaced, improper installation, such as incorrect gap or loose mounting, can cause signal problems.
- Sensor Contact with Reluctor Wheel: If the sensor is not properly positioned, it may come into physical contact with the reluctor wheel, leading to damage or signal interference.
- Foreign Material: Debris or foreign material between the sensor and the reluctor wheel can disrupt the magnetic field and signal generation.
- PCM Issues (Less Likely): In rare cases, the problem may lie within the PCM itself, with a fault in the sensor input circuit. However, this is less common than sensor or wiring problems.
Image of a Crankshaft Position Sensor
Alt text: A close-up view of a crankshaft position sensor, highlighting its electrical connector and sensor tip, illustrating the component responsible for triggering the P0335 code.
Diagnosing the P0335 Code
Diagnosing the P0335 code involves a systematic approach to pinpoint the source of the circuit malfunction. Here’s a step-by-step diagnostic process:
- Verify the DTC: Use an OBD-II scanner to confirm the presence of the P0335 code and check for any other related codes. Record all codes and freeze frame data, which can provide valuable clues about the conditions when the code was set.
- Visual Inspection:
- Sensor Inspection: Visually inspect the CKP sensor for any signs of physical damage, cracks, or contamination. Check the sensor tip for wear or debris.
- Wiring and Connectors: Carefully examine the wiring harness and connectors associated with the CKP sensor. Look for:
- Loose Connectors: Ensure the connector is securely attached to the sensor and PCM.
- Corrosion: Check for green or white corrosion on the connector terminals.
- Wire Damage: Inspect wires for fraying, cracking, melting, or signs of rodent damage.
- Reluctor Wheel Inspection (If Accessible): If possible, visually inspect the reluctor wheel for damage or missing teeth. This may require removing the sensor to get a clear view.
- Check Sensor Resistance: Use a multimeter to measure the resistance of the CKP sensor. Compare the reading to the manufacturer’s specifications. An open circuit or short circuit within the sensor will indicate a faulty sensor.
- Check for Signal at PCM Connector: With the ignition on and engine cranking (or running, carefully), use a multimeter or oscilloscope to check for a signal from the CKP sensor at the PCM connector. This will verify if the sensor is generating a signal and if it’s reaching the PCM.
- Check Circuit Continuity and Short to Ground/Voltage: Use a multimeter to perform continuity tests on the CKP sensor circuit wires.
- Continuity: Check for continuity between the sensor connector pins and the corresponding PCM connector pins to ensure there are no breaks in the wiring.
- Short to Ground/Voltage: Check for shorts to ground and voltage on the sensor signal and reference wires. There should be no continuity to ground or voltage on these circuits.
- Inspect Reluctor Wheel Gap (If Adjustable): Some vehicles may have adjustable CKP sensors. If applicable, check and adjust the sensor gap according to the manufacturer’s specifications.
- Component Testing with Scan Tool: Some advanced scan tools can perform component tests on the CKP sensor, allowing you to activate and monitor the sensor’s signal.
- PCM Diagnostic (Last Resort): If all other tests pass and the P0335 code persists, a faulty PCM may be the cause. However, consider PCM replacement only after thoroughly ruling out all other possibilities.
Image of Diagnostic Steps Flowchart 1
Alt text: Flowchart diagram outlining the initial steps in diagnosing a P0335 Crankshaft Position Sensor circuit malfunction, starting with DTC verification and visual inspection, guiding technicians through a systematic troubleshooting process.
Image of Diagnostic Steps Flowchart 2
Alt text: Continuation of the diagnostic flowchart for P0335, detailing electrical testing procedures such as sensor resistance checks, signal verification at the PCM, and circuit continuity tests to isolate wiring issues or sensor failure.
Fixing the P0335 Code
The repair for a P0335 code depends on the root cause identified during diagnosis. Common fixes include:
- Crankshaft Position Sensor Replacement: If the sensor is found to be faulty based on resistance tests or signal checks, replacing the CKP sensor is the most likely solution. Ensure you use a high-quality replacement sensor that meets or exceeds OEM specifications.
- Wiring Repair: If wiring issues are identified, repair or replace the damaged wires or connectors. This may involve:
- Connector Repair/Replacement: Clean corroded terminals or replace damaged connectors.
- Wire Repair: Splice and repair frayed or broken wires, ensuring proper insulation and secure connections.
- Harness Replacement: In cases of extensive wiring damage, replacing sections of the wiring harness may be necessary.
- Reluctor Wheel Repair/Replacement: If the reluctor wheel is damaged, it will need to be repaired or replaced. This is a more involved repair that may require crankshaft removal in some cases.
- Correct Sensor Installation: If the issue is due to improper sensor installation, reinstall the sensor correctly, ensuring proper gap and torque specifications are followed.
- Foreign Material Removal: Clean any debris or foreign material from the sensor and reluctor wheel area.
- PCM Replacement (Rare): If the PCM is diagnosed as faulty, it will need to be replaced and reprogrammed. This should only be considered after all other potential causes have been ruled out.
After performing any repairs, clear the P0335 code using an OBD-II scanner and test drive the vehicle to ensure the code does not return and the symptoms are resolved. It’s also advisable to monitor the vehicle for a few drive cycles to confirm the repair is successful.
Conclusion
The P0335 Crankshaft Position Sensor A Circuit Malfunction code signifies a problem within the critical CKP sensor circuit, impacting engine timing, fuel delivery, and overall performance. A thorough diagnostic approach, starting with visual inspection and progressing to electrical testing, is essential to accurately identify the root cause. Whether it’s a faulty sensor, wiring issue, or reluctor wheel problem, addressing the P0335 code promptly will help restore your vehicle’s performance, fuel efficiency, and prevent potential engine damage. If you are not comfortable performing these diagnostic and repair procedures yourself, it is always recommended to seek assistance from a qualified automotive technician to ensure accurate diagnosis and repair.
