Volkswagen Touareg P0125: Insufficient Coolant Temp for Closed Loop Fuel Control
P0125 is a generic OBD-II code. If your Volkswagen Touareg has registered it, means that the ECM/PCM is getting a signal from the engine coolant temperature sensor (ECT) that the engine is not warm enough to enter closed loop fuel control. P0125 is usually caused by a bad thermostat, low coolant, or a bad ECT sensor.
P0125 is usually caused by a bad thermostat, low coolant, or a bad ECT sensor
P0125 Symptoms: Volkswagen Touareg
There are not always any noticeable symptoms associated with P0125, particularly if it’s the ECT sensor that has gone bad. If it’s a cooling system issue that is causing the code to appear, you may be experiencing a lack of heating (thermostat stuck open).
Here are some of the symptoms that you may notice with P0125:
- Service engine soon
- Decreased fuel mileage as well as it should (very strong indication of a bad thermostat)
- Torque converter not locking or higher highway RPM
P0125 Causes: Volkswagen Touareg
Here are the most common causes for the P0125 code to register:
Low Coolant
Start your P0125 diagnosis by checking the coolant level. It only takes a moment.
If your Touareg is really low on coolant, it may not have enough for the ECT sensor to register. If it is so low on coolant that the code is registering, the engine can be really hot, even though the ECT sensor is reading low temps.
If the coolant level reads bone dry, don’t fill it up when the engine is hot. Let it cool down first. Introducing room temp coolant to an engine that is overheating can cause a head gasket to blow.
Bad Thermostat or Thermostat Housing
If the coolant level is fine, the thermostat may be stuck open. When this happens the coolant is always cycling through your Touareg’s engine. The cooling system will keep the engine running cooler than it needs to run. This in turn will keep the coolant temperature too cool for closed loop fuel control.
You may notice the heater is not working as well, and that your temperature gauge is not as high as it should be.
Cooling Fan Stuck
If the cooling fan is running when it is not needed, it can cause the coolant to be so much cooler the engine can’t get to the temperature that it needs to run at.
Bad ECT Sensor
If the ECT sensor has gone bad, coolant would still be flowing through the thermostat, and the coolant levels would be full and cycling. Once you verify that, it’s highly likely that the sensor has gone bad. A new ECT sensor isn’t that expensive.
Conclusion: P0125 Touareg
Good luck diagnosing P0125 in your Volkswagen Touareg. If there is anything that you would like to add, please feel free to leave a comment below.
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6.2 Проверка уровня охлаждающей жидкости
Несмотря на оборудование контроля температуры и уровня охлаждающей жидкости, вы должны полагаться не только на индикатор, но и периодически проверять уровень охлаждающей жидкости в расширительном бачке в двигательном отсеке.
- Точно проверить уровень охлаждающей жидкости можно только при неработающем двигателе.
- Уровень жидкости хорошо виден в прозрачном расширительном бачке даже с закрытой крышкой. Когда двигатель холодный, он должен находится между маркировками.
- При горячем двигателе уровень, естественно, выше.
Добавление охлаждающей жидкости
Заметная потеря охлаждающей жидкости является признаком какого-либо нарушения в работе или дефекта. Охлаждающая жидкость не расходуется и не может испаряться из замкнутой системы охлаждения. Иногда при перегреве двигателя может отжаться немного охлаждающей жидкости к запорной крышке. При постоянной потере охлаждающей жидкости нужно проверить систему охлаждения на герметичность так, как описано далее в главе.
- Если при горячем двигателе открывается запорная крышка расширительного бачка, то существует опасность ошпаривания – поэтому соблюдайте крайнюю осторожность.
- Медленно откройте запорную крышку рукой в перчатке или с тряпкой вначале на один оборот и выпустите избыточное давление из системы охлаждения. Лишь после этого полностью отвинтите крышку.
- Если доливается вода, то постепенно разбавляется антифриз, поэтому сразу добавляйте немного антифриза.
- Не наливайте охлаждающую жидкость выше отметки «МАХ»; охлаждающая жидкость расширяется при нагревании, и избыток вытекает из системы.
- Небольшие количества охлаждающей жидкости вы можете доливать в дозаливочный бачок как при прогретом, так и при холодном двигателе.
- При значительной потере охлаждающей жидкости и горячем двигателе не наливайте в расширительный бачок холодную жидкость. Из-за «холодного шока» может деформироваться головка блока цилиндров или треснуть блок двигателя.
В системе охлаждения не одна дистиллированная вода обеспечивает необходимое охлаждение двигателя, а смесь из воды, антифриза и антикоррозийного средства. Поэтому точнее говорить об охлаждающей жидкости или об охлаждающем средстве. Соотношение элементов в смеси для европейских условий составляет 2 : 3, в северных странах 1 : 1.
Coolant Level Check on a 2004 Volkswagen Touareg V6 3.2L V6
Volkswagen Touareg Model Years — 2004, 2005, 2006, 2007, 2008, 2009, 2010
1. Getting Started — Prepare for the repair
2. Open the Hood — How to pop the hood and prop it open
3. Find Reservoir — Locate the coolant / antifreeze reservoir and clean it
4. Check Level — Determine the coolant / antifreeze level
5. Add Coolant — Determine coolant / antifreeze type and add fluid properly
6. Replace Cap — Secure the coolant / antifreeze reservoir cap
7. Locate Hoses — Locate the coolant / antifreeze hoses and connection points
8. Assess Coolant/Radiator Hoses — Tips for how to assess the condition of the hoses
9. More Info. — Additional Information on adding coolant / antifreeze
- BMW of MKE North helped make these videos
Checking the engine coolant (also known as antifreeze) level in your 2004 Volkswagen Touareg is pretty easy. In order to get an accurate reading, your 3.2 liter engine should be cool to the touch when you check it. Engine coolant / antifreeze circulates through your engine to keep it cool in the summer but won’t freeze in the winter. The video above shows you where the coolant reservoir in your Touareg is located and how to check the coolant / antifreeze level. If you need to add anti-freeze, be sure to check your owners manual to determine the correct type of coolant to add — in Volkswagens, it usually located in a section titled Fluid Capacities towards the end of your manual. See our video on how to add engine coolant for tips on adding coolant to your Touareg.
Always wear safety goggles when working on your Touareg. Taking off the coolant reservoir cap on a warm engine could cause the cap to up explosively and fluid to spray out of the reservoir. If you notice an oily surface in your coolant, immediately have your mechanic inspect your Touareg for head gasket leakage.
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Hans Angermeier is an ASE certified Maintenance and Light Repair Technician and has produced over 100,000 videos showing drivers how to fix things on their cars. He has broad expertise on basic repair procedures covering the majority of cars on the road. Over the past 10 years, Hans has been focused on building CarCareKiosk, which is visited by millions of drivers each month.
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P0126 Insufficient Coolant Temperature for Stable Operation
A P0126 diagnostic trouble code (DTC) is a generic powertrain code. That means it applies to all makes/models from 1996-newer but specific troubleshooting steps may depend on the specific vehicle.
Vehicles use an engine coolant temperature (ECT) sensor who’s signal is used by the powertrain control module (PCM) along with other sensors to optimize the vehicle’s operation. It’s important for the engine to warm up and run in a particular temperature range. If the engine does not reach normal operating temperature in the expected time period, this code is triggered.
Based on related discussions in our car repair forums, this particular trouble code seems to be more commonly found on Mazda vehicles, although any vehicle can experience this code. There are a few Mazda technical service bulletins (TSB) regarding this code, so if you have a Mazda, check for appropriate TSBs prior to performing diagnosis.
Symptoms
Symptoms of a P0126 code will include Malfunction Indicator Lamp (MIL) illumination with the P0126 code set in the PCM memory. You may or may not experience increased fuel consumption.
Causes
A code P0126 may mean that one or more of the following has happened:
Possible Solutions
No matter what vehicle you have, you should check for applicable Technical Service Bulletins (TSB) as they pertain to your vehicle. In the case of Mazda, there are some known TSBs and the fix is to reprogram the PCM because this code is triggered due to a "glitch" in the PCM’s programming.
That’s not to say that if you have a Mazda this is the only possible fix. It is still possible there is a physical problem with the wiring, thermostat, etc. Again, refer to TSBs first before replacing parts to see if they apply to you.
Need help?
Let us fix your problem. You are most welcome our diagnosis experts have in most cases the knowledge and skills to find the cause of the error code p0126 and to solve the problems.
«Delete Error Code Permanently, Disable DTC Error Code Function for p0126 in the ECU»
In extreme cases, we even have the option to permanently remove the specific DTC p0126 and disable the function of the specific error code in the ECU. All other fault code functions will then continue to work to protect the engine. This is different from clearing an error code with a diagnostic device. We have the option to permanently remove the function of the specific error code, so that it never comes back. Also emergency running that occurs on the specific error code can be solved in most cases.
Of course we prefer to first try to solve the cause of the error code, but sometimes the only solution is to permanently disable the DTC function of p0126.