Complete Guide to P0393 Trouble Code: Camshaft Position Sensor B Circuit High (Bank 2)
If you own a modern vehicle with dual overhead cams or a V‑engine, you’ve probably heard of the P0393 trouble code. This is one of the most common engine control faults that triggers the check engine light, and it directly affects engine timing, fuel efficiency, and overall performance.
In this guide, we explain what P0393 means, what causes it, common symptoms, and how you can diagnose and reset it at home using the iCarsoft CR Max P professional scan tool.
What Does the P0393 Trouble Code Mean?
P0393 is defined as: Camshaft Position Sensor “B” Circuit High Voltage (Bank 2).
The Powertrain Control Module (PCM) has detected an abnormally high voltage reading from the camshaft position sensor B located on engine bank 2.
This sensor monitors camshaft position and speed, which the PCM uses to control fuel injection timing, ignition spark timing, variable valve timing (VVT), and overall engine performance.
When voltage exceeds factory limits, the PCM stores P0393 and illuminates the check engine light.
Common Symptoms of P0393
- Check engine light illuminated
- Rough idle or unstable idle speed
- Reduced engine power and slow acceleration
- Hesitation or stumbling during acceleration
- Poor fuel economy
- Hard starting or no-start conditions
- Engine misfires at idle or low speed
- Limp mode or reduced engine performance activated
Top Causes of P0393
- Faulty camshaft position sensor B (most common)
- Damaged, shorted, or corroded sensor wiring
- Loose, corroded, or disconnected electrical connectors
- Oil leaks contaminating the sensor or connector
- Weak battery or unstable system voltage
- Mechanical timing issues or worn camshaft components
- Faulty PCM or internal circuit failure (rare)
Why iCarsoft CR Max P Is the Best Tool for P0393
Works with manufacturer-specific engine codes for accurate diagnosis.
View real-time voltage, RPM, and timing values to pinpoint faults.
Works on domestic, Asian, and European vehicles — 58+ makes.
Actuate and test sensors, solenoids, and engine components.
7-inch intuitive display for easy home-mechanic use.
No subscriptions — always updated for new models and codes.
Dealership-level diagnostics at an affordable DIY price.
Saves $100–$300 in unnecessary dealership diagnostic fees.
Step-by-Step: Diagnose & Clear P0393 with iCarsoft CR Max P
- Plug the iCarsoft CR Max P into your OBD II port.
- Turn the ignition key to ON (engine off).
- Select your vehicle make, model, and year.
- Run a Full ECU Scan to read all trouble codes.
- Locate and confirm P0393 in the code list.
- View live data: sensor voltage, engine RPM, timing values.
- Repair or replace the faulty sensor or wiring.
- Use the Clear Codes function to reset P0393.
- Test drive the vehicle to verify the fix.
Frequently Asked Questions (FAQs)
Short trips only. Long-term driving causes misfires, poor timing, reduced fuel economy, and potential engine damage.
DIY: $30–$80 for a cam sensor. Professional: $150–$350 including parts and labor.
Yes — a faulty sensor or high-voltage circuit will almost always trigger P0393.
No. P0393 is camshaft sensor-related — unrelated to the evaporative system.
Most users diagnose and clear the code in just 5–10 minutes.
Yes — fully supports hybrid powertrains and engine control systems.
Yes — crank, MAP, MAF, O2, and many other sensors are supported.
Yes — free lifetime software updates are available online.
Dangers of Ignoring P0393
- Chronic engine misfires leading to internal damage
- Catalytic converter overheating and failure ($1,000+)
- Severely reduced fuel economy
- No-start situations leaving you stranded
- Permanent engine timing and performance issues
Final Thoughts
P0393: Camshaft Position Sensor B Circuit High (Bank 2) is a common but serious engine code that affects timing, performance, and fuel economy.
With the iCarsoft CR Max P professional scan tool, you can quickly diagnose, verify, and reset this code at home without a mechanic.
Don’t ignore P0393. Fix it early, protect your engine, and save money.
Disclaimer: This guide is for informational purposes only. Always consult your vehicle’s service manual or a certified automotive technician before performing engine or sensor repairs. iCarsoft is not responsible for damage from improper tool use or vehicle maintenance.