If you own a BMW produced before 2013, there's a reasonable chance your car uses the N52 powerplant. BMW used this straight-six engine on a wide range of vehicles, including 1-series, 3-series, 5-series, and 6-series cars. This engine is surprisingly reliable, but it does suffer from a handful of common issues, especially as it ages.
One typical problem that can trigger a check engine light relates to BMW's VANOS variable valve timing (VVT) system. VVT systems alter valve timing based on conditions such as engine load, allowing engineers to maximize performance and efficiency under different conditions. Unfortunately, BMW's VANOS system can also be a potential source of trouble.
Understanding P1520, P1523, and P1397
P1520, P1523, and P1397 are the three engine codes you'll typically receive when your car's VANOS system begins to experience issues. P1520 and P1523 refer to the actuator solenoids in your VANOS system, and you may also receive the manufacturer-specific 2A82 and 2A87 codes. These codes provide the same information but refer specifically to the VANOS intake and exhaust solenoids.
On the other hand, P1397 is a generic code that indicates a faulty reading from the camshaft position sensor. A faulty VANOS solenoid can cause your engine's camshaft timing to be incorrect. As a result, your car's computer believes the data from the camshaft position sensor is faulty, causing it to trigger the generic P1397 code.
In general, you'll need to look at the whole picture to determine the underlying problem. If you receive a P1397 in combination with additional codes, you shouldn't rush to condemn the sensor. Instead, it's crucial to determine if faulty VANOS solenoids may be at fault. Rushing to replace the sensor can mean spending extra money to replace a part that's working correctly.
Resolving Your VANOS Problems
Faulty VANOS solenoids will usually cause drivability issues in addition to triggering your check engine light. You may even notice these problems before your computer detects an issue. The most common symptoms are a noticeable change in idling behavior and loss of power. In some cases, these problems may come and go or become gradually more severe over time.
While a faulty VANOS solenoid is unlikely to cause any significant damage to your engine, it can leave you stranded. If the problem becomes severe enough, your car may stall, go into limp mode, or even refuse to start. Once you notice these symptoms, you should take your car to a shop specializing in BMW engines as soon as possible.
Fortunately, resolving VANOS problems is relatively straightforward, and any experienced BMW mechanic should be able to identify and isolate the issue quickly. Taking care of this problem is an easy and low-cost way to bring back the performance you know and love.