What Does P0392 Mean?
The camshaft position sensor B on bank 2 is reporting a low input signal to the ECM. The voltage on the signal wire is below the minimum threshold the ECM expects. For a Hall-effect sensor, this means the output is stuck near ground voltage; for a magnetic sensor, the amplitude is too weak for the ECM to detect tooth transitions. The engine may run on reduced performance mode, experience misfires on bank 2 cylinders, or exhibit a no-start condition.
Common Causes
30%
CMP sensor B (bank 2) signal wire shorted to ground
25%
Failed CMP sensor B with shorted internal windings or stuck-low Hall-effect output
20%
Corroded or oil-contaminated sensor connector causing signal attenuation
15%
Excessive sensor-to-reluctor air gap from improper installation or worn mounting
10%
Missing or damaged sensor 5V reference supply (Hall-effect sensors only)
Diagnostic Steps
1
With the ignition on and engine off, measure the voltage at the CMP sensor B (bank 2) signal wire at the ECM connector. A near-0V reading with the sensor disconnected (on a Hall-effect type) indicates a short to ground in the wiring.
2
Disconnect the CMP sensor B and check resistance between the signal wire and ground at the harness connector. Near 0 ohms confirms a short to ground. Progressively unplug intermediate connectors to isolate the shorted section.
3
For Hall-effect sensors: verify 5V reference is present at the sensor connector. For magnetic sensors: measure internal resistance (typically 500-1500 ohms) and check for shorts between signal pins and the sensor body/ground.
4
Inspect the area around the CMP sensor B for oil leaks from the valve cover gasket. Oil intrusion into the connector is a common cause of signal degradation on bank 2 sensors located under or near the valve cover.
5
If wiring and connector are clean, verify the sensor air gap. Remove the sensor, clean the tip, inspect the reluctor pattern through the bore, and reinstall to the correct depth. Some sensors bottom out against the reluctor and must be shimmed.
Estimated Repair Cost
$60 - $400
Parts + labor, varies by vehicle and location
The camshaft position sensor B on bank 2 is reporting a low input signal to the ECM. The voltage on the signal wire is below the minimum threshold the ECM expects. For a Hall-effect sensor, this means the output is stuck near ground voltage; for a magnetic sensor, the amplitude is too weak for the E...
The most common cause of P0392 (Camshaft Position Sensor B Circuit Low Input (Bank 2)) is: CMP sensor B (bank 2) signal wire shorted to ground
Typical repair costs for P0392 range from $60 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A low CMP signal on bank 2 causes the ECM to lose camshaft position data for that bank. The engine will typically still run using other sensors but may be in a reduced-power limp mode. The vehicle can be driven to a repair facility at moderate speeds. Not an immediate safety hazard but should be repaired soon.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0392 to identify the root cause.
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Quick Info
Category
Powertrain
System
Variable Valve Timing / Engine Timing System
Difficulty
Type
Generic (SAE)
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