Throttle Actuator Control Range/Performance (Bank 1)
P0638 indicates that the Powertrain Control Module (PCM) has detected a discrepancy between the actual throttle position and the commanded position for Bank 1. This typically points to a malfunction in the electronic throttle control system, which may be caused by a faulty throttle actuator, a sticking throttle plate, or issues with the accelerator pedal position sensor or wiring. The code is set when the PCM determines that the throttle actuator is not responding within the expected range or performance parameters.
01. Most Common Causes
- Faulty throttle actuator motor
- Carbon buildup on throttle plate causing sticking
- Faulty accelerator pedal position sensor
- Wiring or connector issues in the throttle control circuit
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power or limp mode
- Poor acceleration or hesitation
- Rough idle or stalling
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm P0638 and check for other codes.
Step 2: Visually inspect the throttle body for carbon buildup or sticking.
Step 3: Test the throttle actuator motor and accelerator pedal position sensor with a multimeter.
Step 4: Check wiring and connectors for damage, corrosion, or loose connections.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with P0638 as it can cause sudden loss of throttle control or reduced engine power, leading to unsafe driving conditions.
How much does it cost to fix?▼
The cost to fix P0638 typically ranges from $50 to $150 for diagnostic and cleaning, but could be higher if parts like the throttle body or sensors need replacement.