P0393 code definition
The P0393 code is stored when the PCM detects an abnormally high voltage reading from the camshaft position sensor circuit for camshaft sensor B in engine bank 2. This code may be stored with crankshaft sensor codes.
What the P0393 code means
The PCM monitors the camshaft position to ensure that the engine is running at optimal levels. If the PCM detects a voltage reading from engine bank 2’s camshaft position sensor B circuit, which is more than 10% higher than the manufacturer’s specifications, the P0393 code will be stored.
What causes the P0393 code?
The most common cause of the P0393 code is damaged electrical components, such as wiring, due to leaking oil or other engine fluid. Other causes may include:
- Contaminated engine fluid
- Bad camshaft sensors
- Bad crankshaft sensors
- Faulty starter motor
- Weak battery
- Faulty starting system circuit
What are the symptoms of the P0393 code?
Some vehicle owners may only notice the illumination of the Check Engine Light. However, others may experience symptoms such as a total loss of power, a stalled engine, choppy acceleration, or rough idling.
How does a mechanic diagnose the P0393 code?
After verifying the P0393 code with an OBD-II scanner, the mechanic should begin by looking for leaking fluid that could have caused shorts or corrosion within the electrical components. Any issues should be repaired, and the code should be cleared from the system. If the code reappears after a retest, the mechanic should then perform voltage tests on the sensor, manually comparing the information to the manufacturer’s specifications.
If the readings are within the correct limits, then the sensor needs to be replaced. However, if the readings are not within the correct limits, the mechanic should continue checking each possible cause, clearing the code and retesting the system after each attempt, to be sure that the correct solution is found.
Common mistakes when diagnosing the P0393 code
In most cases, a misdiagnosis comes in the form of a replaced sensor. It is important to diagnose every possible component, particularly the electrical components, before replacing any major part.
How serious is the P0393 code?
Without the PCM’s ability to properly control the position of the camshaft, the vehicle will experience larger problems. It is very important to address the cause of the P0393 code right away, before more damage occurs.
What repairs can fix the P0393 code?
In order to repair the P0393 code, a mechanic may attempt any of the following:
- Repairing any electrical components, such as wiring, that have been damaged by leaking engine fluid, as well as repairing the source of the leak
- Replacing bad camshaft sensors
- Replacing bad crankshaft sensors
- Replacing a faulty starter motor
- Repairing or replacing a weak battery
- Replacing a faulty starting system circuit
- Replacing contaminated engine fluid with new fluid
Additional comments for consideration regarding the P0393 code
If either the camshaft or the crankshaft sensors are faulty in the case of the P0393 code, it is best to replace both units at the same time. Most manufacturers report that these two components work best when the wear is identical.
Need help with a P0393 code?
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