What Does P2173 Mean?
The PCM has detected sustained high airflow through the throttle body that exceeds expected values for the commanded throttle position. This indicates a chronic air intake issue rather than a sudden event.
Common Causes
35%
Vacuum leak in intake manifold, gaskets, or hoses
30%
Throttle body not closing properly due to carbon buildup or damage
15%
Failed throttle position sensor giving incorrect readings
12%
Improperly calibrated or failed MAF sensor
8%
PCV system malfunction allowing excessive airflow
Diagnostic Steps
1
Step 1: Use smoke machine to identify vacuum leaks throughout intake system
2
Step 2: Remove and inspect throttle body for carbon deposits preventing full closure
3
Step 3: Monitor throttle position sensor readings at idle and verify plate closes completely
4
Step 4: Check MAF sensor readings against known-good values for idle conditions
5
Step 5: Test PCV system operation and check for stuck-open PCV valve
Estimated Repair Cost
$100 - $900
Parts + labor, varies by vehicle and location
The PCM has detected sustained high airflow through the throttle body that exceeds expected values for the commanded throttle position. This indicates a chronic air intake issue rather than a sudden event.
The most common cause of P2173 (Throttle Actuator Control System - High Air Flow Detected) is: Vacuum leak in intake manifold, gaskets, or hoses
Typical repair costs for P2173 range from $100 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
High idle speed and difficulty controlling engine speed may occur. Vehicle may be difficult to slow down or exhibit surging.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2173 to identify the root cause.
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Quick Info
Category
Powertrain
System
Air Intake and Throttle Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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