P0638 OBD-II Trouble Code: Throttle Actuator Control Range/Performance (Bank 1)

Our certified mechanics come to you · 12-month, 12,000-mile warranty

SCHEDULE P0638 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0638 code

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 for $70.00. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $30.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$70.00$30.00
Toyota$70.00$30.00
BMW$70.00$30.00
SCHEDULE P0638 DIAGNOSTIC Get a fair and transparent estimate upfront

Check Engine Light

P0638 code definition

This diagnostic power train code represents a problem happening with the vehicle’s throttle actuator control range in bank one.

What the P0638 code means

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.

What causes the P0638 code?

There are a number of potential causes that could trigger the P0638 trouble code. The most common versions would be:

  • A malfunctioning pedal position sensor
  • A malfunctioning throttle position sensor
  • A malfunctioning throttle actuator motor
  • The throttle body is dirty
  • The connection is loose or dirty
  • The wiring harness is loose or dirty

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.

What are the symptoms of the P0638 code?

There are really only two main symptoms associated with the P0638 code:

  • The vehicle may hesitate to accelerate when you put the pedal down
  • The check engine light is on

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.

How does a mechanic diagnose the P0638 code?

To diagnose the problem causing the P0638 code, do the following:

  • Hook up your OBD-II scanner and download the freeze frame data for your customer’s car. Make sure you look at any other trouble codes that may have been stored in the vehicle’s PCM. In some cases, you will need to resolve these before you fix the throttle problems.
  • Even if the customer swears they are having throttle problems, take it for a quick test drive to see for yourself. If the problem was a temporary issue, the code may still be stored despite the throttle working fine.
  • Finally, inspect the throttle body to look for signs of problems with the connection, wire, systems, etc.

Common mistakes when diagnosing the P0638 code

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.

How serious is the P0638 code?

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.

What repairs can fix the P0638 code?

Try the following:

  • Clean out the throttle body
  • Replace any bad connections
  • Fix the wire system

Additional comments for consideration regarding the P0638 code

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.

Need help with a P0638 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

P0638
trouble codes
Check Engine Light

Fast and easy Check Engine Light is on Inspection service at your home or office.

SCHEDULE P0638 DIAGNOSTIC
Get a fair and transparent estimate upfront

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.5/5

Number of Reviews

4,004

Rating Summary
3,661
169
45
25
104
3,661
169
45
25
104
Joel

Joel

18 years of experience
562 reviews
Joel
18 years of experience
Great service ..i recomend joel for everyone
2003 LEXUS LS430 - CHECK ENGINE LIGHT IS ON - JACKSONVILLE, FLORIDA
Rigoberto

Rigoberto

8 years of experience
556 reviews
Rigoberto
8 years of experience
He was thorough in explaining to me what need to be done to resolve the issues with my vehicle, I was satisfied with my appointment with Rigoberto and I will be requesting him to work on my vehicle. Thank you ☺
2003 NISSAN PATHFINDER - CHECK ENGINE LIGHT IS ON - NILES, ILLINOIS
Chris

Chris

20 years of experience
1374 reviews
Chris
20 years of experience
He gave my car a lot of effort, and I was happy with how it all went.
2017 HYUNDAI IONIQ - CHECK ENGINE LIGHT IS ON - DANA POINT, CALIFORNIA
Kenneth

Kenneth

17 years of experience
385 reviews
Kenneth
17 years of experience
Completely satisfied he was on time very professional. And he made I understood what was going on I'm definitely recommending Kenneth to my Co worker's thank you so much Kenneth. Ms. Felecia!
2008 BUICK LUCERNE - CHECK ENGINE LIGHT IS ON - LONG BEACH, CALIFORNIA

More related articles

How to Get a Louisiana Driver's Permit
s licensing program. The first step in this program is to obtain...
Veteran and Military Driver Laws and Benefits in New Mexico
The state of New Mexico offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...

Related questions

Q: My car has the OBD-II codes P0030 and P0135 for the heater control circuit and sensor. Where is this sensor located?

This is a code that pertains to the heater side of your oxygen sensor. The heater is required to raise the temperature of the sensor so that it can operate properly. Simply unplugging relays/fuses will not keep the code from...

Q: hi i recently bought a rebuilt transsmison for my 2000 chevy silverado 4x4 5.3. i can get my truck to shift right and im geting to

You should have the computer scanned to get the failure codes and have them diagnosed first and then you may know the cause of transmission problems and check engine light.

Q: All engine sensor failure, transmission problems after a car wash.

Hi there. The only thing that could cause the severe issues that you are having with your vehicle is a leak in the exhaust system and having cold water enter the catalytic converter causing the chamber to collapse. Check the...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1-800-701-6230 · hi@yourmechanic.com