Throttle Actuator Control Range/Performance Bank 1
Table of contents
P0638 MERCEDES-BENZ Possible Causes
- Faulty Accelerator Pedal Position Sensor
- Accelerator Pedal Position Sensor harness is open or shorted
- Accelerator Pedal Position Sensor circuit poor electrical connection
- Faulty Throttle Positioner Motor
How do I fix code P0638 MERCEDES-BENZ?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Tech Notes
- Mercedes Benz Code = 0193 (Throttle valve actuator): Mechanical fault (P0638)
- Mercedes Benz Code = 0194 (Throttle valve actuator): Mechanical fault (P0638)
- Mercedes Benz Code = 0212 (Throttle valve actuator): The component was replaced without performing throttle valve adaptation (P0638)
- Mercedes Benz Code = 0228 (Throttle valve actuator): Throttle valve jamming (iced up) (P0638)
Cost of diagnosing the P0638 MERCEDES-BENZ code
The cost of diagnosing the P0638 MERCEDES-BENZ code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
P0638 MERCEDES-BENZ Description
This fault code is stored in the engine control module when a fault is detected with the throttle positioner motor. The ECM monitors the current flow through the motor and if the current flow is exceeds a predetermined limit this fault code is logged. The ECM uses a comparator circuit to monitor the current flow. A mechanical detect within the throttle valve assembly can effect current flow. Mechanical condition of the throttle valve assembly should be investigated before any electrical fault finding procedure.