P0392 code definition
A P0392 code identifies incorrect voltage or waveform from the camshaft position sensor circuit. It is specifically for the camshaft sensor "B" in engine bank 2.
What the P0392 code means
P0392 is an OBD-II generic code that occurs if the powertrain control module perceives an incorrect camshaft position. The camshaft position sensor is a fixed part that uses an electromagnetic field along with the notches of the camshaft to deliver data about camshaft position to the PCM. This, in turn, allows the module to properly calculate ignition timing and fuel delivery. The code is generated when the voltage exceeds 10% of the manufacturer's value.
What causes the P0392 code?
Typically, the P0392 code is due to:
- Oil or engine fluid leaking on electrical connectors, wires or sensors and leading to them becoming grounded or shorted
- Camshaft sensor failure due to leaked fluids
- Defective crankshaft sensor
- PCM failure
What are the symptoms of the P0392 code?
The P0392 code is usually accompanied by such symptoms as delays in engine start, very rough idling of the engine, sluggish or unreliable acceleration, poor engine performance and even a vehicle with a no-start situation. The service engine light may also illuminate.
How does a mechanic diagnose the P0392 code?
The P0392 code is diagnosed with the OBD-II scanner, and then a visual inspection of all wiring is performed. Any needed repairs or replacements must be done before clearing the codes and retesting. If the code reappears, the mechanic will have to monitor waveforms and look for inconsistence in the performance of the camshaft, distributor and crankshaft sensors. They will also look for signs of fluid leaks and perform voltage testing on the sensors. This means that repairs require the scanner, an oscilloscope, and a digital ohm meter.
Common mistakes when diagnosing the P0392 code
Many technicians blame the sensor for triggering the code without first testing the entire system. There are many areas where failure may occur and because the code covers the entire circuit for the camshaft position sensor, a thorough diagnosis is needed. The camshaft position sensor interacts with the reluctor ring at the end of the camshaft, and when it passes the sensor it interrupts the pattern from the sensor to the PCM. This is something that has to match the pre-programmed timing in the PCM and so it is important that you diagnose the cause carefully.
How serious is the P0392 code?
When a vehicle records the P0392 code, it is at risk for a no-start condition. The camshaft is perceived by the PCM as being in the wrong location, and it will cause a chain reaction of unpredictable behaviors. Though it may mean nothing more than a lack of engine performance, it is an issue that must be repaired immediately. It may be due to leaked or leaking fluids, and this is a problem that will only worsen and cause further degradation of parts.
What repairs can fix the P0392 code?
Standard repair steps for the P0392 code will include:
- Validating the code by clearing it and retesting
- Performing a visual inspection of wiring and connections, repairing and replacing any components, connectors, fuses or wires as needed
- Doing a visual inspection to look for leaking fluids and resulting damages
- Using an oscilloscope to look for inconsistent waveforms in the camshaft, distributor, and crankshaft sensors
- Testing and replacing the camshaft sensor and crankshaft sensor if their voltages are not to manufacturer's specifications
- Checking system continuity and resistance, including the PCM
- Replacing and reprogramming the PCM if needed
Additional comments for consideration regarding the P0392 code
The failure of a PCM is a very rare event and should be the mechanic's last issue to test if all other steps reveal no problems or inconsistencies.
Need help with a P0392 code?
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