DTC P0638: Notes

WARNING: This page is about a different car, the 2007 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.

DETECTION CONDITION AND POSSIBLE CAUSE (DTC P0638)

DTC P0638	Throttle actuator control circuit range/performance problem
DETECTION CONDITION	The PCM compares the actual TP with the target TP when the engine is running. If the difference is more than the specification, the PCM determines that there is a throttle actuator control circuit range/performance problem. Diagnostic support note This is a continuous monitor (CCM). The MIL illuminates if the PCM detects the above malfunction condition during the first drive cycle. PENDING CODE is available if the PCM detects the above malfunction condition. FREEZE FRAME DATA is available. The DTC is stored in the PCM memory.
POSSIBLE CAUSE	Throttle actuator malfunction Throttle valve malfunction PCM malfunction

DTC P0638

Throttle actuator control circuit range/performance problem

DETECTION CONDITION

The PCM compares the actual TP with the target TP when the engine is running. If the difference is more than the specification, the PCM determines that there is a throttle actuator control circuit range/performance problem.

Diagnostic support note

This is a continuous monitor (CCM).
The MIL illuminates if the PCM detects the above malfunction condition during the first drive cycle.
PENDING CODE is available if the PCM detects the above malfunction condition.
FREEZE FRAME DATA is available.
The DTC is stored in the PCM memory.

POSSIBLE CAUSE

Throttle actuator malfunction
Throttle valve malfunction
PCM malfunction