P2174
Throttle Actuator Control System - Sudden Low Air Flow Detected
A sudden, large drop in MAF/MAP signal not matched by a pedal change — typically intake restriction, MAF failure, or actively-stuck-closed throttle plate.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Symptoms
- Check engine light on
- Reduced throttle response, possible limp mode
- Hesitation or surging
- Idle too high or too low
Common causes
Ordered by how often each turns out to be the cause.
- Intake severely restrictedCommon
Parts involved
- Electronic Throttle Body
- Mass Air Flow Sensor
P2174 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.