Help with my Peugeot 308 eml code p2173

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Vlatko
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Help with my Peugeot 308 eml code p2173

Post by Vlatko »

Hello,

I have a Peugeot 308 2012 e-hdi 112hp, and in the last few weeks - since the temperatures outside dropped, i have a EML showing up on the dash.

I took the car to Peugeot main dealer, it showed p2173 air metering valve, throttle body position too open i think. Since the new part was gonna cost 250 euros at the dealer, i ordered a second hand one, but in good condition, from a car with the same engine as mine and only 55kkm.

I installed the part myself, the error cleared itself up after i turned on and off the engine a few times.. and i thought i solved it... and the error came up once again the next morning. The light comes up when the temperature outside is around 3 to 4 degrees celsius, and its always the same error code.

Later in the day, when it gets hotter outside, the error turns itself off... till the next morning. It drives me crazy :?

Today, while i was driving, the engine was in operating temperature, the light was off, and the suddenly in 4th gear at around 2100 rpm the light showed up again, and the car went into limp mode, the heating in the mirrors turned on.. and the engine sound was different.. as it was in dpf regenerating state. Still the same code.

Can someone please help?

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mickthemaverick
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Re: Help with my Peugeot 308 eml code p2173

Post by mickthemaverick »

This is only a wild idea and there are certainly far more knowledgeable people around but I wonder if the external temperature sensor is giving a true reading. It sounds to me that the ecu may be receiving incorrect data and acting accordingly? Good luck with it. :)

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Vlatko
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Re: Help with my Peugeot 308 eml code p2173

Post by Vlatko »

Hmm, never thought of that.

Where is the the external temp sensor located anyway?
Seems to me that the temperature shown on the display in the car is the same as outside? Or thats not the external temp sensor?

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Re: Help with my Peugeot 308 eml code p2173

Post by Hell Razor5543 »

The temperature sensor is normally located in a little dome on the underside of a wing mirror.

The temperature shown on the main display (and NOT the heating controls) is from the external temperature sensor. It is normal for the external and internal temperatures to be different.

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mickthemaverick
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Re: Help with my Peugeot 308 eml code p2173

Post by mickthemaverick »

Well if the gauge on the dashboard seems to read correctly then it is probably ok. It was just a wild thought anyway, the sensor is usually mounted just behind the front grill or in a side mirror housing. Someone who knows far more than me about Peugeots (which isn't difficult :-D ) will hopefully be online soon and be able to advise you. :)
Last edited by mickthemaverick on 06 Jan 2021, 20:09, edited 1 time in total.

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mickthemaverick
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Re: Help with my Peugeot 308 eml code p2173

Post by mickthemaverick »

This video may help find it!!

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Vlatko
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Re: Help with my Peugeot 308 eml code p2173

Post by Vlatko »

Haha, i always wondered whats that little rubber like dome on the underside of the wing mirror :)

I had a wild thought the other day that it might be the air intake temp sensor thats faulty.. sending wrong info to the ecu. But thats not the error code im receiving.

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mickthemaverick
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Re: Help with my Peugeot 308 eml code p2173

Post by mickthemaverick »

You may find this helpful, I borrowed it from a diagnostic companies website :-D

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.

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
Replace TPS sensor replacement
Repair to any wiring harness that affects the induction system.
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.

Good luck :-D

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Vlatko
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Re: Help with my Peugeot 308 eml code p2173

Post by Vlatko »

Basically replace everything on the air intake path :D

I replaced the MAF last month, since it was giving me troubles.

If its indeed a vacuum leak-and i thought of that one too, afaik it will probably throw error codes most of the time?
I get error code if the outside temp drops below 4 degrees celsius.
Was thinking of spraying brake cleaner in the air intake path these days, so i'll let you know what happens.

Just a thought- as i replaced the throttle body, does it need to be registered with the car ecu afterwards or is just plug and play?

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mickthemaverick
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Re: Help with my Peugeot 308 eml code p2173

Post by mickthemaverick »

Not a clue re registering the throttle body although I wouldn't have thought so, but another thought is whether you have a chafed vacuum pipe somewhere which tends to leak when it contracts under cold temps? :?: :)

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Vlatko
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Re: Help with my Peugeot 308 eml code p2173

Post by Vlatko »

Is there a diagram of all the vacuum hoses and sensors in the engine so i can check them one by one? 1.6 e-HDi dv6c 112hp.

I can write the VIN number if that helps.

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mickthemaverick
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Re: Help with my Peugeot 308 eml code p2173

Post by mickthemaverick »

If you post up the VIN which will be obscurred so only forum admin can read it and then you may have to make a donation (usually a tenner) to the forum and you will be able to access all the diagrams that are available. The donation lasts for 2 years so its excellent value in my opinion as you will be able to get all sorts of diagrams and parts information. I expect Marc will pick up your query and let know what to do. Cheers :-D

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Vlatko
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Re: Help with my Peugeot 308 eml code p2173

Post by Vlatko »

Thanks mickthemaverick.

I think i found the culprit..

This morning i started the car and immediately the fault appeared.
Shut off the engine and deleted the error, then i heated the ambient temp sensor just by touching it to around 7 degrees, and then started the car. The fault was gone!

So i thought it might be the air intake temp sensor, since theres no chance for me to preheat that sensor, but searching the net it shows two different kind of sensors.

Either this:
Image

Or this:
Image

Anybody knows the difference and which one is the right one?

Still a bit confused as to why air intake temp makes a problem that the ECU thinks its the throttle body.

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Vlatko
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Re: Help with my Peugeot 308 eml code p2173

Post by Vlatko »

Does anybody knows if the new throttle body should be recalibrated and registered first in lexia, so the car doesnt think its the old throttle body?