Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer is having trouble controlling the part that makes the car go faster when you press the gas pedal. It's like when a toy car's remote control isn't working right.
The P0638 code is triggered when the Engine Control Module (ECM) detects a problem with the throttle actuator control system's performance or range on bank 1.
The throttle actuator controls the amount of air entering the engine. The ECM monitors the throttle position and adjusts it based on input from various sensors. If the ECM detects that the throttle actuator is not responding as expected, or if the throttle position is out of the expected range, it will store the P0638 code.
• Check Engine Light is on
• Poor acceleration
• Engine stalling or running rough
• Faulty throttle body
• Wiring issues in the throttle actuator circuit
• Defective throttle position sensor
Throttle Actuator: A device that controls the throttle position electronically.
ECM: Engine Control Module, the computer that controls the engine's functions.
• Use an OBD-II scanner to verify the code and check for other related codes.
• Inspect the throttle body for dirt or damage.
• Check the wiring and connectors in the throttle actuator circuit for damage or corrosion.
• Clean or replace the throttle body if necessary.
• Repair or replace damaged wiring or connectors.
• Replace the throttle position sensor if faulty.
• OBD-II scanner
• Multimeter
• Screwdrivers
$150 - $600
Moderate
• Toyota Camry
• Honda Accord
• Ford F-150
• Regularly clean the throttle body.
• Inspect wiring and connectors for damage.
• Perform routine maintenance checks.
Engine Performance
• Do not ignore the Check Engine Light.
• Seek professional help if you're not confident in diagnosing the issue.
Repairs may be covered under the vehicle's powertrain warranty if applicable.
This code has been commonly reported in vehicles with electronic throttle control systems since the early 2000s.
Moderate – Address the issue soon to prevent further engine performance problems.
Driving with this code may lead to reduced engine performance or stalling, which can be dangerous.
• Engine at operating temperature
• Vehicle in idle or driving conditions
The throttle actuator is typically located on the throttle body, which is connected to the intake manifold.
Q: Can I drive my car with a P0638 code?
A: It's not recommended as it may lead to reduced engine performance or stalling.
Q: How do I reset the P0638 code?
A: After repairs, use an OBD-II scanner to clear the code. If the issue is fixed, it should not return.
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