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P0638 is a diagnostic trouble code (DTC) for "Throttle Actuator Control Range/Performance (Bank 1)". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
This diagnostic power train code represents a problem happening with the vehicle’s throttle actuator control range in bank one.
In many newer model vehicles, the throttle body is hooked up to a drive by wire system. This controls the throttle body through a sensor on the automobile’s gas pedal, an electric actuator motor that’s inside the throttle body and the Powertrain Control Module (PCM) or Engine Control Module (ECM).
This PCM/ECM leverages the throttle position sensor (TPS) to keep track of the actual throttle blade position on the vehicle as well as when the position is no longer in range of the target range. If it picks up that the throttle blade position is no longer in range, the P0638 code will show on the scanner. Bank one refers to the location of cylinder number one on the engine. Usually, though, you’ll get a code that simply signifies a problem with any of the cylinders as one throttle body covers all of them.
That being said, if the vehicle does have this type of throttle body, there’s little you can do to fix a problem similar to P0638. The majority of the time, your only option will be to simply replace it. In the event of a motor failure, these engines are designed to be held open thanks to their spring actuation. In some cases, though, like when a complete failure occurs, the throttle will be totally unresponsive and the vehicle will only move at extremely slow speeds.
There are a number of potential causes that could trigger the P0638 trouble code. The most common versions would be:
As you can see, many of these problems can be addressed through fairly simple means. A lot of times, it just takes a bit of cleaning. However, if you go through the above potential causes and none of them seem to be behind it, keep in mind that the problem could also be that the PCM/ECM has malfunctioned.
There are really only two main symptoms associated with the P0638 code:
Obviously, you may notice both too. With the throttle open, you should definitely notice a problem with trying to accelerate, whether the check engine light comes on or not.
To diagnose the problem causing the P0638 code, do the following:
Not taking the vehicle for a test drive is definitely a mistake. If you don’t notice anything, the PCM may be acting up. However, you also want to carry out a full inspection just in case. Check for a faulty cylinder or problems with the fuel injector.
This is a pretty serious problem. For one thing, until the underlying problem is fixed, there’s always the possibility that the vehicle won’t start. Far worse, though, is the fact that the automobile may become difficult to drive while it’s already on the road.
Try the following:
Although poor acceleration may not seem like it needs to be a huge priority, this is a problem that could cause a crash, so it’s best to address ASAP.
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