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Autopart Mechanic

Autopa ... 4/5/2018

2012 BMW X1 xDrive28i 6 Cyl 3.00L

Preventive Maintenance

How do I diagnose Throttle Actuator Control System High Airflow of a car when OBD scanner is showing P2173 Trouble Code

1 Answer

PartsAvatar Ca

PartsAvatar Ca 4/5/2018

What the P2173 code means?

Code P2173 means that there is a vacuum leak somewhere in the intake system or one or more of the
sensors that monitors intake pressures has malfunctioned.

What causes the P2173 code?

The most likely cause of this code being stored is a binding throttle plate caused by carbon build up on the
inner bore of the throttle body. In this case, the throttle plate is held open inadvertently and the PCM
recognizes the excessive airflow as a malfunction. The next most common malfunction is a defective
manifold air pressure sensor. A defective throttle actuator control, throttle position actuator, throttle
position sensor, or an engine vacuum leak could also be the cause of such a code. Other causes may
include corroded, open, or shorted wiring or connectors in the CAN Bus harness, a loose control module
ground strap or broken ground wire.

What are the symptoms of the P2173 code?

Malfunction Indicator Lamp (MIL) or ABS warning lamp illumination

Engine may not start

Either no or low throttle response

Automatic transmission will not shift

Additional codes are possibly set

Common mistakes when diagnosing the P2173 code?

Throttle position actuators and sensors are frequently replaced in error when a simple cleaning of the inner
throttle bore could have rectified the situation. Drive-by-wire throttle body components are typically not
serviceable as individual parts and require replacement of the entire throttle body. Symptoms and stored
codes that are present as a reaction to a communication failure are often misdiagnosed and repaired as the
cause of the problem. Obviously, this leads to an unsuccessful repair. Engine misfire codes, lean exhaust
codes, fuel injector codes, and virtually any other drivability or transmission code that is accompanied by a
controller communication code can potentially be a pitfall for misdiagnosis.

What repairs can fix the P2173 code?

Replace lower intake manifold gaskets

Replace upper plenum gaskets or seals

Replace EGR gasket or valve leak

Replace brake booster

Replace broken vacuum hose to the brake booster

Replace broken vacuum hose

Replace PCV hose.

Replace MAP sensor replacement

Replace MAF sensor replacement


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