P2173 – Throttle actuator control (TAG) system – high airflow detected

By Bojan Popic (Contact Me)
Last Updated 2023-10-12
Master Mechanical Engineer

Table of Contents

1. What Does Code P2173 Mean?
2. Where is the P2173 sensor located?
3. What are the common causes of code P2173 ?
4. Get Help with P2173

What Does Code P2173 Mean?

NOTE: While this guide is specific to vehicles made by Jeep, Dodge, or Chrysler, P2173 is a generic OBD2 diagnostic code. If your vehicle is not a Jeep, keep in mind the following information will only apply to some vehicles. If you have a Jeep with this code, we hope the detailed information below helps you. Please comment below the article with your year, model, engine type, and mileage, and we will respond and try to help.

The generic description for the P2173 trouble code is Throttle actuator control system – high airflow detected, which will be triggered when the PCM detects more air is going into the engine’s intake than it should.

While many of you probably know how the intake airflow is controlled, we’ll briefly explain it for those who don’t. While running, the engine draws the air through the intake, which then mixes with fuel and gets compressed before being ignited. The amount of air and consequent engine speed is determined by the throttle body, which opens and closes depending on how much the driver is pressing the throttle.

A partially shut throttle plate will cause a vacuum inside the intake manifold, which is constantly monitored by the MAP sensor. If this pressure is higher than a predetermined limit, the PCM will conclude something is preventing the correct intake airflow regulation and trigger the P2173 trouble code.

Where is the P2173 sensor located?

Regardless of the model or engine type, the throttle actuator – aka throttle body – is always located at the beginning of the intake manifold. In addition, the MAP sensor can be found somewhere on the manifold’s plenum. On in-line engines, the intake is fitted at the side of the cylinder head, while on V6 and V8 engines, it sits at the top of it.

More precisely, cars commonly affected by the P2173 trouble code have a so-called Tigershark 4-cylinder MultiAir engine. Here, the intake manifold is at the front side, facing the radiator. This puts the throttle body approximately at the center of the vehicle, as shown in the photo below.

In addition, the MAP sensor is found at the intake manifold, near the power steering pump.

What are the common causes of code P2173 ?

Vacuum leak
The P2173 trouble code is likely triggered by a vacuum leak, which allows air to uncontrollably enter the engine. This can be caused by a broken intake manifold gasket, insufficiently tightened throttle body, or a cracked hose – this can be the one that connects to the EVAP solenoid, PCV valve, or the EGR. Apart from the code, leaks like these can affect engine performance at idle and low revs.

PCV hose modification
On certain 2017 – 2018 Jeep Renegades with a 1.4-liter engine, the problem might be caused by excessive flow through the PCV system, which is solved by fitting a restrictor into the PCV vapor tube. See Jeep’s service bulletin 09-010-20 for more details.

Faulty throttle body
In most cases, cars affected by the P2173 have an electronically controlled throttle body (fly-by-wire) operated by the PCM. Here, the stepper motor opens and closes the throttle plate, while the throttle position sensor monitors its position. But should an issue with the signal from this sensor develop, the PCM won’t be able to precisely control the throttle plate movement, which may result in high intake airflow.

MAP sensor issues
Another common problem that may set the P2173 code is issues with MAP readings, which can be caused by a faulty MAP sensor, damaged wiring, or a poor connection. Performing the usual diagnosis, which involves measuring voltages and resistances, should reveal if this is the case.

PCM software update
On 2007-2008 Jeep Compass and Dodge Calibers, the PCM might falsely detect a high-airflow situation when there isn’t one. Updating the PCM’s software, as described in the service bulletin 18-019-08, should solve the issue. It’s quite the same with the 2019 Jeep Renegade, whose repair procedure is given in the service bulletin 18-006-23.

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