Audi A8 D2 Engine Control Unit Ecu

I like to write near automotive topics—particularly DIY stuff and auto concepts.

Mercedes Benz Engine

The engine control module (ECM) is likewise known as the powertrain command module (PCM) or the engine control unit (ECU).

The master responsibleness of this controller is to get information from sensors and run certain actuators. In the instance of any errors, the ECU shows a bank check engine light on your dashboard.

We will discuss where and why sensors are placed in certain positions and requite some insight every bit to how or what the sensors sense. If you are a DIY person, then you lot could even open up the sensors yourself and clean them for optimum signals to reach your ECU.

Powertrain Control

Engine Control Module

No affair how complicated, you lot'll find the sensors beneath in any EFI engine:

1. Engine coolant temperature
2. Air temperature
3. Barometric force per unit area/manifold absolute pressure
4. Mass air menstruum
5. Idle air controller
6. Crankshaft
7. Camshaft
8. Throttle position
9. Oxygen
10. Knock

Engine coolant temperature sensor

ECT

Location of ECT sensor

ECT

Engine Coolant Temperature Sensor (ECT)

Similar humans, a vehicle needs to maintain a specific temperature in order to role properly. Also cold, and the vehicle will drink too much petrol. Too hot and the head gasket could leak. Coolant is a liquid used in the vehicles radiator of the car to maintain the temperature at which the engine tin can perform at its optimum.

The engine coolant temperature sensor simply tells the car'southward estimator (ECM) the current temperature of the vehicle. When the temperature of the coolant reaches between 75 and 95 degrees (depending on the manufacturer specifications), the ECM instructs the radiator fan to turn on and start cooling downwardly the liquid.

• Usually information technology is located either on the bottom of the radiator, or by follow the summit radiator hose towards the engine block. Y'all'll come across information technology on mounted on the engine block.
• Information technology can exist cleaned using a wire brush when you entirely change your engine coolant (approx. every 80,000 km or l,000 miles).

Intake air temperature sensor

IAT

Location of intake air temperature sensor

IAT

Air Temperature Sensor (IAT)

The intake air temperature sensor (IAT) tells the ECM the temperature of the air that is going into the engine. The cooler the air, the ameliorate the performance of the engine, which is probably why you might accept noticed a difference in the auto'south performance on a summer night equally compared to the day.

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• It is usually located on the air filter box or the pipage going from the air filter box to the throttle body. Toyota has a MAF and an IAT sensor congenital in one unit which has five wires located on the air filter box.
• It tin exist cleaned once every six months (depending on dust/pollution), using carb cleaner on an ear cleaner.

Manifold accented pressure sensor

MAP

Location of MAP sensor

MAP

BARO/Manifold Accented Pressure Sensor (MAP)

The baro sensor measures the ambient air force per unit area, which tells the ECM the current distance of the vehicle. If you're driving in the mountains yous'll demand less fuel, because there is less oxygen in the atmosphere and therefore less oxygen in the engine cylinder. The ECM will adjust the fuel injectors "throwing time" or pulse width accordingly.

The map sensor detects the vacuum force per unit area created inside the intake manifold of the vehicle and sends the engine load information to the ECM. The ECM will accommodate the fuel injectors pulse width accordingly.

Note: Baro and MAP sensors look and piece of work in a similar way, therefore simply i of the two sensors volition be found in one engine.

• Unremarkably found either bolted on the intake manifold or linked with a vacuum pipe from the intake manifold.
• If mounted on intake manifold and then should exist cleaned every 6 months to 1 year, using carb cleaner (depends on fuel quality where you alive; the lower the quality of fuel, the more than carbon deposits found). I've had to clean some every 3 months.

Mass air menses sensor

MAF

Location of MAF sensor

MAF

Mass Air Catamenia Sensor

The Mass Air Flow sensor is responsible for measuring the volume of air entering the engine.

The sensor contains a heated sensing element, as shown in the picture above. The temperature of this chemical element has to exist kept constant, simply is cooled by the air passing through the intake. The MAF sensor produces more than current to keep the temperature at the level required by the manufacturer. There is a small estimator in the MAF which calculates the internal current catamenia to oestrus the element, and by using this figure information technology can calculate the volume of air going into the engine besides as the air density and temperature. The ECU uses this information to accommodate the injector pulse width and spark (ignition) timing.

• The MAF Sensor is located either on the air cleaner box or forth the pipe going from the air cleaner to the throttle body.
• Annotation: Since the MAF sensor calculates the air density, the engine does not demand the MAP or baro sensor readings. Therefore you lot will not see a MAP or baro sensor in your engine if y'all accept a MAF installed and vice versa.
• Can exist cleaned with carb cleaner or MAF cleaner spray and ear cleaning bud. Clean if you see dust or carbon deposits.

Idle air control valve (Japanese makes).

IACV

Idle air control valve (seen in Hyundai models).

IACV

Location of IACV on typical Japanese vehicle.

IACV

Idle Air Controller (IACV)

The Idle Air Control Valve (IACV) is responsible for keeping the RPM of the engine steady. The IACV is actually an actuator and not a sensor because it does non supply readings to the ECM, just works on the command of the ECM. I just added this actuator for the DIY enthusiast.

There are two coolant pipes connected to the housing, which yous can see on the far right of the flick shown. The black piece shown in the movie is a magnetic actuator which rotates the valve shaft allowing it to open and shut as required by the ECM.

Whenever you first your car the IACV will increase the RPM until the coolant temperature sensor (ECT) tells the ECU that the temperature of the engine is up-to the manufacturers specifications. The RPM will and then drib downwards to and remain steady at approx 800 rpm whenever there is an actress load on the engine the idle controller adjusts and compensates for the load applied—for example, switching from park to drive mode in an automatic transmission vehicle, or even when you switch on your air conditioning. You lot tin besides adjust the idle speed of the vehicle by loosening the screws on the actuator and rotate the actuator. The default setting of the actuator is ordinarily in the heart.

• Located on the throttle trunk of the vehicle.
• Depending on fuel quality, carbon deposits build upwards and the valve shaft gets stuck resulting in fluctuating RPM signals on the dashboard.
• To clean remove the black magnetic actuator which will reveal the shaft. Try rotating the shaft with your fingers. If information technology'due south a trivial difficult, so apply carburetor cleaner and a toothbrush or ear cleaning bud to clean the area of the valve (the 2 identical rectangular blocks), and check to come across if the shaft is easy to rotate. When putting the magnetic sensor back, brand sure the condom O-band goes on the metal housing and and so align the tip of the shaft with the footstep inside the magnetic sensor. Fix the sensor to the mid-position and tighten the screws.
• Notation: On some vehicles a scanner is required to reset the idle controller once opened.

Throttle position sensor.

TPS

Location of throttle position sensor.

TPS

Throttle Position Sensor (TPS)

The throttle position sensor (TPS) is linked from the accelerator pedal to the throttle torso.

The TPS tells the ECM that the commuter is pressing the accelerator pedal. The ECM can also verify this data with the MAP or MAF sensor readings, thus increasing the injector pulse width and spark (ignition) timing.

• The TPS is located on the throttle body. Honda has an adaptable TPS sensor and if the initial if your RPM is high and cannot exist controlled through the IACV, and so the voltage readings of the TPS should exist checked. The normal reading for a Honda is close to 0.6V at idle.

I retrieve playing with the TPS in my friend's auto and adjusting his TPS to about 2.5 volts at idle. The issue: The became a gas guzzler, consuming near thirty litres of petrol (about seven gallons) in 30 km (about 18 miles). I guess we learned the difficult way.

A newer system for the throttle control came in 2003-2005 and newer models of vehicles, in which a throttle cable is no longer used. A sensor has been placed in the accelerator pedal and the TPS sensor has been replaced with a throttle position motor.

• This sensor never requires cleaning. If you do desire to clean something on it and so just make clean the connector points with electric contact cleaner and a toothbrush. That goes for all the sensors.

Camshaft position sensor.

CMP

Camshaft Position Sensor

The camshaft position sensor (CMP) is electro-magnetic and produces a voltage when a metallic object moves past. This sensor is responsible for telling the ECM the current position of the camshaft. With this information the ECM can summate which valve is open and throw fuel through the injector into that cylinder.

• This sensor is found on ane end of the camshaft, usually on the correct side in a front cycle drive car. It's normally non very difficult to access.
• Cleaning can be done with a simple dry cloth, simply if the oil has been used for likewise long, a golden-brownish stain is left on metal portion of the sensor. In some cases it even comes out blackness and gooey, which is basically old engine oil turned into sludge. if it's stained then you tin can use a wire-brush or very fine sandpaper to remove the stain. Brand certain no metal bits remain on the sensor. If you need some liquid type material to become some stains off, attempt WD-40.

Crankshaft position sensor.

CKP

Comparison of CMP and CKP sensors.

CMP & CKP sensors

Crankshaft Sensor (CKP)

This sensor is very like to the cam position sensor in functionality. Information technology is responsible for telling the ECM the exact location of the crankshaft as well as the RPM (rotations per infinitesimal) of the engine. With this data the ECM knows the position of each piston in each cylinder. Using the cam sensor readings, as well as the creepo sensor readings, the ECM knows exactly which injector needs to exist activated. The synchronization of the cam and crank shafts in an engine is the central to engine operation. This synchronization is as well referred to every bit the engine timing. With the correct timing you will get the fuel and spark delivered at the correct time.

• It is located at the bottom of the engine somewhere shut to the crankshaft.
• Cleaning technique for this sensor is exactly the aforementioned as the cam sensor. Cleaning once a year is proficient enough for this sensor.
• Annotation: If your car does not start, a possible reason could be a faulty crank sensor or a broken wire in the crank sensor circuit.

Oxygen sensor.

O2

Oxygen Sensor (O2)

The oxygen sensor (O_ii) is responsible for "smelling" the exhaust fumes and detecting the oxygen content in society to make sure the engine is consuming the right corporeality of fuel. The ratio maintained past the ECM is 14.7 parts air to 1 function fuel. This is known as the air/fuel ratio.

There are 2 types of oxygen sensor: zirconia or titania. These are materials which tin find oxygen and produce a voltage. The voltage range falls betwixt 0.1V to 0.9V.

I normally use a vehicle scanner to check the maximum and minimum readings of the oxygen sensor. If I run into both peaks, and then I know the sensor is working fine. If the voltage max is 0.8 then I open up the sensor for cleaning. Sometimes the sensor produces a constant voltage but does not fluctuate. This generally means the sensor needs to exist replaced.

Knock sensor.

Knock

Knock Sensor

The knock sensor contains a piezoelectric crystal. This crystal is able to discover mechanical stress and produces a voltage when the car knocks or pings. Under heavy acceleration, information technology sends signals to the ECM and the ECM retards the ignition timing to recoup for the knocking, which in effect protects the pistons and rings from damage.

Knocking likewise occurs when using low-grade fuel and having the knock sensor allows y'all to use different grade fuels without causing engine harm.

• This sensor is unremarkably bolted onto the main-body of the engine in the most difficult and awkward positions. Lucky this sensor never requires cleaning.

What Happens If Ane of These Sensors Fail?

If a sensor fails and gives aberrant readings, for instance a coolant temperature sensor giving a constant reading of -40^o, then the ECM goes into fail-condom way. This ways it basically ignores the values of the sensor at mistake and tries to either calculate the value of the failed sensor or assumes a constant reading and then the vehicle can go along running. Some faliures like a crank sensor or a MAF sensor will result in the vehicle not starting at all.

This commodity is accurate and true to the best of the author'due south noesis. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

Questions & Answers

Question: Subsequently cleaning my 1999 Honda Accordance iv cylinder 2.three l VTEC all the carbon out of the intake system. My car starts to run, then stalls out and will not start back upwardly. What's the problem and what should I check?

Answer: Cheque MAF / MAP sensor electrical grip (whichever your car has) and expect for air leaks.

Question: What allows for an engine to be diagnosed?

Respond: Whatever malfunction in the sensors or mechanical issues.

Question: I am in the UK and have a Seat Leon with 1.4tsi 150bhp. If I drive off in the morning, the engine warning light comes on after about 5 mins. The code reader shows fault code PO11F re ECT sensor. Can this be erased & non come back until next 24-hour interval? The car otherwise runs fine. If I start and so end before driving off in the morning, the alert light does not come on at all. I'm wondering if the fault could be related to an ECU remap I did. Firm that did the remap is adamant that the mistake isn't related. Is that true?

Answer: PO11F In most cases seems to bespeak toward emissions rather than the ECT. Even though the vehicle shows and ECT mistake there is an underlying problem which will not fix the problem even if you change sensors. I would say get-go, check the fuel pump force per unit area when yous turn they key in the ON position (priming; without starting the engine). Second; check if your Catalytic converter is choked (if you have problems with fuel consumption). In another source, the code given is associated with overheating and a blown caput gasket or fifty-fifty a pocket-size timing belt issue. It could be one of these but cannot be confirmed equally I'm not entirely sure what the remap includes. Try to eliminate the easier ones to see if it works. If the easy ones don't do it then expect until the light stays on longer and comes on more oftentimes to check the rest.

Question: Is the controller for the heater on an O2 sensor in the ECM?

Answer: Heater location is inside the O2 sensor. Heater is controlled by the ECM and then there would be a scrap on the ECM lath that would control the O2.

Question: My 2010 Ford Mustang 4.0 is hiccuping, jerking, and it feels like it's hesitating to advance. When I'm making a complete terminate the car volition shut itself off. Why is this the instance?

Answer: Look for air leaks in the intake area.

Question: My Nissan sunny 2004 model cranks but does non pick upward and the injectors do not spray fuel. What can I practise?

Reply: Modify CAM sensor and endeavour.

Question: Can my 2000 Toyota car without a camshaft sensor make itself eat fuel? Tin I clean the frazzle sensor to make information technology work again?

Answer: If the exhaust sensor is dead it volition non work again. If the readings are not in the correct range then cleaning can meliorate information technology. Excessive fuel consumption is only if the MAP sensor has stopped working. You will encounter blackness smoke come out of the frazzle if that is the instance. If that is not happening and so your fuel filter could be choked and needs replacing or valve clearances need to exist checked specially on the exhaust side.

Question: My auto is mark 2 ii.0cc .2002 model. When I kickoff it, I notice a odour of fuel and the fuel consumption is a little high. What can I do?

Respond: Check for leaks in fuel rails

Question: Tin can y'all tell me where the ECM is on a 1984 Pontiac 6000?

Respond: Not exactly sure. Some sources say in the air filter box in the engine bay and others say in the dashboard. Y'all could follow the sensor wiring loom to get to the PCM.

Question: how tin I tell if the knock sensor is faulty?

Answer: You lot will get a bank check engine low-cal which will indicate it is faulty. If in that location is no indication then it is fine and the problem is somewhere else. If still in dubiousness then supervene upon it.

Question: My Cadillac cts 05 has a code reading u0100 and check engine light and will not become over 2rpm would like to know what'south wrong?

Answer: A bit of a serious issue with either the wiring or the command module. The ECM cannot pick upward signals from either the engine or the transmission modules.

A rat could have eaten upwardly the wires or the connections may be loose. You volition have to trip the rug and follow the wiring to brand sure information technology'southward all good. If all good then try changing the controller units. Continuity test between the cables to detect faulty cables. The problem lies in the main network of cabling; not the sensors. Information technology will continue to stay in limp manner (2mph) until the upshot is fixed.

Question: Is a sensor & module for the transmission considered the same part?

Answer: No. A module is a separate ECU that controls the transmission. Sensors give the module information. Have a expect at the manual command module article I have written to become more than info on the types of sensors used with the transmission control module.

Question: We had some problem codes leading us to set up our TPS and IACV simply nosotros even so have black smoke and high idling and occasionally stalls. No trouble codes now, any idea which direction to take?

Answer: Confirm the TPS is installed properly. Sometimes it does not rotate if in the wrong position. With the ignition on press, the accelerator pedal and either utilise a multimeter on the sensor wires or using a scanner make certain the voltage is approx 0.6v with nothing pressed then press the accelerator pedal to "wide open up throttle" position. At wide open up throttle, it should be approximately 4.5volts. If these are correct then Make sure IACV is set up to the heart point of the 2 screws making sure at that place are no air leaks in the throttle area. You lot can employ some silicone to ensure that.

Some vehicles (like Chevrolet) require a throttle reset through a scanner. It volition never run properly until y'all reset using the scanner. Taking the battery terminals doesn't work either.

If everything is good and still have black smoke and so effort replacing MAP/MAF sensor. that should comprehend it. If problems persist and then send me an electronic mail with a snapshot of diagnostic voltages at idle (running engine) and another snapshot later on quick heavy revs... it gives the max and minimum of each sensor which is what I would like to await at.

Question: My Toyota Camry's (2004) temp guess always go halfway and never go college fifty-fifty my Cooling fan failed. Then I test my coolant sensor by an Ohm meter and the sensor last Voltage past Voltmeter and the reading is ok. Is in that location a possibility that the ECM reading is commencement and demand to be calibrated?

Reply: If the reading is ok then keep using it. The Camry has a large radiator which allows for natural cooling; this is why the fan doesn't always go on.

If your water levels are stable in the cooling system and then I would propose leaving it as it is.

Question: If my temperature estimate is not working at all does this hateful all the sensors have problems?

Reply: If the temperature gauge or any sensor fails you will get a cheque engine light. When this happens the car uses default values set past the manufacturer.

Question: 1999 Vauxhall Corsa 1.two 16v not revving past 3000 rpm, Sounds like it's revving of the limiter, simply simply at 3000rpms, what could crusade this?

Respond: Sounds similar the ECU is keeping the motorcar in limp (safety) mode. You lot need to check with a scanner to see what could exist causing information technology. Sometimes it's the oxygen sensor, other times it could be the injectors.

Question: What would keep the cheque engine from coming on in a 97 Dodge v.nine?

Reply: It could be annihilation; you will demand to go it scanned to become the code.

Question: Other than engine sensor signals, name three other inputs signals an engine control module might receive?

Reply: Turbo, Evaporative emissions control, vtec solenoid, oil control valve.

Question: My country cruiser shows a code 1421 with autel (master cylinder scan, cylinder pressure sensor). Where is the location of this sensor?

Answer: On the brake master cylinder. Look for grips near the brake fluid reservoir. It could be a broken wire, or the grip may not be on properly. If everything seems ok and then try replacing the sensor.

Question: My Toyota Auris Rx 1.8 2009 model cooling fan or thermal switch does non run whenever my engine is on and even when I drive only my temperature never overheated why is this?

Answer: The cooling fan works with the thermal switch. The thermal switch will take a sure indicate (I.eastward.93 degrees Celsius) at which it volition enable the current to the cooling fan. Your vehicle also has a thermostat valve which allows for the rotation of coolant within the engine. This valve also has a set temperature at which it volition open to allow the cold coolant to enter the engine.

Now if you have a thermal switch which is set to run when the coolant reaches 93 degrees and also take a thermostat valve that allows for the rotation of coolant at approximately 87 degrees and so the vehicle does not demand the fan. It will only engage in very hot weather where the radiator cannot cool the contents (coolant) quick plenty.

Question: How should I troubleshoot a changing sound from the mainfold and a bad sound on the superlative?

Answer: Check for air leaks.

© 2012 Irfan

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Audi A8 D2 Engine Control Unit Ecu

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