P2173 OBD-II Trouble Code: Throttle Actuator Control System - High Airflow Detected

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P2173 code

P2173 is a diagnostic trouble code (DTC) for "Throttle Actuator Control System - High Airflow Detected". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $89.99 . Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.0 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford $89.99 $20.0
Toyota $89.99 $20.0
BMW $99.99 $20.0
SCHEDULE P2173 DIAGNOSTIC Get a fair and transparent estimate upfront

P2173 code definition

Throttle Actuator Control System - High Airflow Detected

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 Powertrain Control Module (PCM) monitors the intake manifold pressures for calculating air fuel ratio. The most likely cause of this code will be a vacuum leak. The intake manifold is the primary culprit when a vacuum leaks occur, but there is many other systems tap into the intake manifolds vacuum supply. If any other systems should leak vacuum, a vacuum leak will occur. The list of components and systems are as follows:

  • Vacuum leak
  • Manifold Absolute Pressure (MAP) sensor
  • Mass Airflow (MAF) sensor
  • Exhaust Gas Recirculation (EGR) valve
  • Broken vacuum hoses connected to the intake manifold
  • Short to power or ground in the 5 volt reference circuit
  • Vacuum brake booster
  • PCM
  • Electronic Throttle Control System (ETCS) / Throttle Body

Note: The ETCS is actually more than one component:

  • Throttle Position Sensor (TPS)
  • Throttle Valve Actuator
  • Throttle Valve

What are the symptoms of the P2173 code?

This code is set when the PCM believes there is excessive air entering the engine. When this occurs, it creates a lean running condition, meaning there is too much air in comparison to fuel. When this condition exists, the motor will usually misfire. Most identify this as rough running. Other possible symptoms are as follows:

  • High idle
  • Poor fuel mileage
  • Check Engine Light
  • Hesitation
  • Lack of power
  • Overheating
  • Hard start
  • Crank no start

How does a mechanic diagnose the P2173 code?

The primary cause of this code is a vacuum leak. This is what this code is suppose to indicate. For this reason the technician should expect to find a vacuum leak. Locating a vacuum leak can be done in a variety of ways.

First step to any diagnosis is to observe. Often times a vacuum leak will make a loud whistle or whooshing sound. Simply following the sound to its source will confirm the problem. If there isn’t any obvious sound, than there are two other techniques commonly used.

Lightly spraying a mist of starter fluid, brake cleaner or carburetor cleaner in suspected areas will often reveals a vacuum leak. When one of these sprays enters into the intake manifold via a vacuum leak or throttle valve, the motor will react with a change in RPM (revolutions per minute). Spray these chemicals liberally at a suspected and localized area. If a mist were to engulf the entire engine compartment and there is a change in RPM, then there is no way to know where the mist entered the motor. For this reason lightly spraying at suspected areas is necessary to isolate, where there is a possible intake leak.

Another technique that often reveals the source of air leaking into a motor is with the use of a smoke machine. This should be used with the motor off and connected to a vacuum port. This machine creates smoke under pressure that it injects into the intake manifold and all the vacuum lines connected to it. As the pressure builds in the intake system, smoke will be forced out of any vacuum leak in the entire system. A smoke machine is often used to diagnose EVAP systems as well.

If there is no sign of a vacuum leak, the next thing the technician should suspect is a problem with the system that the PCM uses to monitor intake manifold pressures. The PCM uses the induction (Induction is the process of sucking air into a motor for combustion) monitoring system to adjust air fuel ratio depending on the conditions in the intake manifold. It is this system that will detect excessive air flow into the motor. This system consists of the MAP or MAF sensor, TPS, EGR valve, PCM, O2 sensor, intake manifold and any system that uses vacuum to operate.

Often times this system simply misinterprets the information it receives from these sensors and sets the wrong code. A malfunction in any of these sensors will usually set the appropriate code for their malfunction, but this is not always the case. Knowing the difference depends on the experience of different technicians.

Common mistakes when diagnosing the P2173 code

A thorough check for vacuum leaks is often harder said than done. If a technician fails to find the leak, he or she may suspect a sensor problem and spend a lot of time testing each suspected sensor one at a time, only to find that they are all good. The next process will be to again look harder for a vacuum leak. Vacuum leaks can occur in unexpected places sometimes making them challenging to identify.

After a thorough inspection of the vacuum system and it is determined there isn’t a vacuum leak, the technician should look closer at the scan tool data. This data isn’t always simple to interpret. All sensors use a 5 volt reference instead of the unsteady 13 to 15.5 volts that exist when a vehicle is running. The 5 volt reference is in place to give the PCM a constant, and steady reference point for any changes that occur in all sensors. If this 5 volt reference is compromised by a short to ground or power, the results are unpredictable.

Often times disconnecting each sensor one at a time and monitoring the reference voltage with a multimeter is necessary to pinpoint a problem. The programming in each vehicle will differ year to year and manufacturer to manufacturer. For this reason, the results of a sensor failure or reference voltage corruption is often one of the most challenging system to diagnose.

How serious is the P2173 code?

This code is moderately serious only because it is likely to accompany drivability symptoms. In the case of a very large vacuum leak, which is likely to make the car un-drivable, burnt valves in the head is possible. Most drivers will call a tow truck at this point, but for those who choose to continue driving, more problems can be created.

In most cases there will be annoying drivability symptoms that motivates the owner to seek a mechanic. It is possible on some vehicles to only exhibit mild symptoms and a Check Engine Light, but different codes are usually set.

What repairs can fix the P2173 code?

Most likely a vacuum leak will need to be repaired. Vacuum leaks can occur from many sources.

Additional comments for consideration regarding the P2173 code

This code is only used by Chrysler vehicles and on a few years model of Hyundai’s. This includes Jeep and Dodge vehicles. In addition to its little use, Chrysler assigns two different code definitions to this code. The official OBD-II (On Board Diagnostics, Version II) code definition is the one stated at the beginning of this article. The alternate definition used by Chrysler products is “High Airflow/Vacuum Leak Detected (Slow Accumulation).” Either way, the code indicates there is a vacuum leak. The alternate Chrysler code repair procedure directs the technician to the EGR valve first.

Need help with a P2173 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

Check Engine Light
trouble codes
P2173

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P2173 code.

SCHEDULE P2173 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(6455)

Rating Summary
5977
227
53
36
162
5977
227
53
36
162
 at YourMechanic

Jequan

7 years of experience
8 reviews
Jequan
7 years of experience
Volkswagen GTI L4-2.0L - Check Engine Light is on - Morrisville, North Carolina
Timely and very detailed. Explained the issue to me and recommended steps to take to fix it. Very courteous and helpful.
 at YourMechanic

Theodore

16 years of experience
1418 reviews
Theodore
16 years of experience
Ford Expedition V8-5.4L - Check Engine Light is on - Bothell, Washington
Exceeded my expectations again. Excellent mechanic! I will continue to request for all of my cars needs.
 at YourMechanic

Chris

18 years of experience
435 reviews
Chris
18 years of experience
Jeep Liberty V6-3.7L - Check Engine Light is on - Plano, Texas
Chris is awesome! He got us fixed up with no troubles at all. The pain of dealing with a shop are just nonexistent and Chris himself is a super nice guy and great mechanic!
 at YourMechanic

Corey

16 years of experience
188 reviews
Corey
16 years of experience
Ford Focus L4-2.0L - Check Engine Light is on - Charlotte, North Carolina
Corey was prompt. He was experienced with Fords, and gave the impression he had dealt with everything. He presented the problem in a way that was easily understood for a layman, and gave the quote like a pro. He detailed the next steps in the process. I can't say I'm happy with the problems, but I'm satisfied that I have someone handling it who knows his way around.


More related articles

P2712 OBD-II Trouble Code: Hydraulic Power Unit Leakage Intermittent
P2712 means there is low pressure usually caused by a leak in the the hydraulic power unit or also faulty sensors & solenoids or electrical issues.
P2253 OBD-II Trouble Code: O2 (Oxygen) Sensor Negative Current Control Circuit High Bank1 Sensor 1
P2253 P2253 code definition O2 (Oxygen) Sensor Negative Current Control Circuit High Bank1 Sensor 1 What the P2253 code means P2253 is a generic OBD2 diagnostic trouble code (DTC) indicating a fault with the bank 1 sensor 1 O2 sensor....
P0244 OBD-II Trouble Code: Turbocharger Wastegate Solenoid A Circuit Range/Performance
P0244 code definition Turbocharger Wastegate Solenoid A Circuit Range/Performance What the P0244 code means P0244 is an OBD-II generic code indicating that...

Related questions

P0089 code, fuel pressure regulator performance low. Went into limp mode, then next morning no start

After doing a little research on your particular situation, it looks as though this is a fairly common problem with this model of vehicle. I would suggest contacting your local dealership about the situation due to the fact that I...

Check Engine Light is on, trouble code P0011&12. I changed the oil and filter. I need to turn off the engine light to see if that problem is solved.

Hello. If the oil level was low or if the wrong oil war previously used then that can cause these codes to come up. Most of the time though, on this engine, it is caused by a failure in the...

Can shaft position sensor all of the outcomes of the problem

Possibilities: 1 - Simply replacing the camshaft sensor will solve your problem. 2 - If it does not, with the age of the vehicle, there can be a break in the wiring harness to the cam sensor. 3 - If...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com