What Does P0394 Mean?
The camshaft position sensor 'B' on bank 2 is sending an intermittent or erratic signal to the ECM. This sensor monitors the rotational position and speed of the exhaust camshaft on the side of the engine opposite cylinder #1. The driver may experience intermittent stalling, rough idle, hard starting, or momentary hesitation during acceleration. The check engine light may flash on and off as the fault comes and goes.
Common Causes
35%
Damaged or corroded wiring/connector at camshaft position sensor B (bank 2)
30%
Failing camshaft position sensor with intermittent internal fault
15%
Excessive camshaft endplay or worn cam journals causing variable air gap
12%
Damaged or missing reluctor ring teeth on exhaust camshaft (bank 2)
8%
ECM ground or power supply issue causing intermittent sensor readings
Diagnostic Steps
1
Monitor the camshaft position sensor B (bank 2) PID live data — watch for signal dropouts, erratic frequency changes, or voltage spikes during idle and at 2,000 RPM.
2
Inspect the sensor connector and wiring for corrosion, backed-out pins, chafing against engine components, or oil contamination. Wiggle the connector and harness while monitoring live data to reproduce the intermittent fault.
3
Using a DVOM, check sensor resistance (typically 800–1,400 ohms for Hall-effect types) and compare to bank 1 sensor. Backprobe the signal wire and verify 0.3–4.8V AC signal while cranking.
4
Remove the sensor and inspect the reluctor ring/tone wheel for missing or damaged teeth, debris buildup, or excessive air gap (spec: 0.5–1.5mm typically).
5
Check the cam-to-crank correlation using a scope — overlay bank 2 exhaust cam signal with the crankshaft position signal to verify timing alignment and consistent signal pattern.
Estimated Repair Cost
$80 - $350
Parts + labor, varies by vehicle and location
The camshaft position sensor 'B' on bank 2 is sending an intermittent or erratic signal to the ECM. This sensor monitors the rotational position and speed of the exhaust camshaft on the side of the engine opposite cylinder #1. The driver may experience intermittent stalling, rough idle, hard startin...
The most common cause of P0394 (Camshaft Position Sensor "B" Circuit Intermittent (Bank 2)) is: Damaged or corroded wiring/connector at camshaft position sensor B (bank 2)
Typical repair costs for P0394 range from $80 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle can be driven cautiously for short distances, but the intermittent nature of this fault means the engine could stall without warning. Avoid highway driving until diagnosed. Prolonged driving may cause catalytic converter damage from misfires.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0394 to identify the root cause.
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Quick Info
Category
Powertrain
System
Engine Timing / Variable Valve Timing
Difficulty
Type
Generic (SAE)
Recommended Tools
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