Maf sensor testing pdf

I think i will not play anymore with testing and cleaning. Pdf mass air flow and temperature sensors testing by scan. Mass air flow maf sensors the mass air flow sensors converts the amount of air drawn into the engine into a voltage signal. Dtc p0102 mass air flow maf sensor circuit low frequency circuit description the mass air flow maf sensor measures the amount of air which passes through the sensor into the engine during a given time. The symptoms of a bad mass air flow sensor include low engine power, poor fuel economy, an engine that wont start, a check engine light on the dash and a gas smell from the exhaust fumes. Assuming this test is done at or near sealevel, the peak output of the sensor in. Pdf in this paper an experimental setup was designed and realized in laboratory to test and measure the engine mass air flow sensor used in. The job of the mass air flow sensor is to keep track of the. The sensor connects to the intake manifold with a rubber hose, depending on your particular application. Cam sensor ckp crank sensor cmp air flow sensors ammmaf engine coolant sensor ect throttle position switch tps heated oxygen sensors hego accelerator position app map sensor map knock sensor ks. How to troubleshoot a mass airflow sensor axleaddict.

Maf sensor while doing a full throttle run in 2nd gear, as shown in figure b. The data from the maf sensor is simply a voltage between 0v and 5. Testing of the ho2s this way assures that the catalytic converter will remain efficient. Take your vehicle to a professional auto electrical shop for further testing. How to test a mass air flow maf sensor without a wiring diagram. Sometimes, a maf sensor s hot wire breaks or gets damaged.

Connect a scan tool to see the maf sensor parameter identification data pid information. Attach the voltmeter or tachometer negative probe to the ground black wire and the positive probe to the signal wire. In this paper an experimental setup was designed and realized in laboratory to test and measure the engine mass air flow sensor used in engine applications. The electronic circuit component measures this change in temperature and converts it to a voltage or frequency signal. Automotive sensor testing diagnostic strategies of modern automotive systems book 1 kindle edition by concepcion, mandy. Chapter 7 potentiometerposition sensor tests tps, evp, app, vaf etc chapter 8 pressure sensor testing, map, baro, dpfe, fuel tank and rail pressure sensors chapters 9, 10 and 11 the 5v reference and signal circuit quick tests chapter 12 mass airflow sensor testing chapters 14, 15,16 fuel delivery and fuel pressure testing chapters. Pdf experimental stand to evaluate engine mass air flow. Cam sensor ckp crank sensor cmp air flow sensors amm maf engine coolant sensor ect throttle position switch tps heated oxygen sensors hego accelerator position app map sensor map knock sensor ks exhaust gas temperature fuel temperature sensor egr position sensor inputs ignition coils idle speed control valve iscv. A mass airflow maf sensor in a modern ford vehicle is located inside the air intake duct. This test will help you check the condition of this wire. Inputs sensors the egr temperature sensor is located in the egr passage and measures the temperature of the exhaust gases.

A hands on presentation of how to test and measure maf sensor readings. A maf sensor that behaves like this will require replacement. Maf sensors fitting and diagnosis issues professional. To find out if this tutorial applies to you specific vehicle, take a. Nov 09, 2017 according to this, the maf sensor signal wire is the one labelled as number 3. This measurement allows the ecu to perform adjustments which ensure that the engine is performing to an optimum level. What type of voltage signal is produced by a vaf and what would you expect to. The hot wire component of the maf cools when air mass flows past. There are few types of air flow sensors, however, modern cars use a hotwire type. Basically, the maf sensor measures the amount of air flowing into the engine through the air cleaner assembly, which contains the air filter and connects to the throttle body. According to this, the maf sensor signal wire is the one labelled as number 3. The main function of the mass air flow maf sensor is to measure the volume of air passing through it, and therefore into the combustion chamber of the engine. How to test a ford mass air flow sensor it still runs.

A maf sensor that continuously overreports or underreports airflow into the engine will cause an engine to run rich or lean. In reality, egr flow is nothing more than a vacuum leak downstream from the maf sensor. Page 45 mass air flow maf sensor test procedure testing is done onvehicle. It uses a hot wire element to measure the amount of air entering the engine.

If you have a voltage type, you will use a voltmeter. Automotive sensor testing diagnostic strategies of modern. Additionally, since maf sensors are somewhat pricey, many technicians are afraid to condemn them, fearing either the customers or the boss wrath if their diagnosis is not borne out. In modern cars, an intake air temperature or iat sensor is built in the mass air flow sensor. Chapter 12 mass airflow sensor testing scannerdanner. Obdii is a system that was mandated by the federal epa and was developed by the society of automotive engineers sae. Mechanics measure the amount of air flow mass air flow sensor readings. The photos below compare the stock afm installed on an e30 m3 on the left with the maf 4. I also show you how you can figure out the wires without a. How to test a maf or map sensor with a multimeter plus.

Much more common, however, are failure modes in which the maf sensor has become unreliable, underreporting or overreporting the true airflow into the engine. And when you needed a bosch, you could only get a pierburg for a fair price. Autozone carries hundreds of thousands of parts and accessories. Chapters 4 and 5 fuel trim and oxygen sensor testing chapter 6 temperature sensor, thermistor circuit tests chapter 7 potentiometerposition sensor tests tps, evp, app, vaf etc chapter 8 pressure sensor testing, map, baro, dpfe, fuel tank and rail pressure sensors. In this tutorial, im gonna show you how to do it with just a multimeter and in stepbystep manner. If you have a mass airflow sensor with pulse output, connect the emulator to start the engine and. Computers and sensorsoperation,diagnosis,and service 593 figure 253 many electronic components are used to construct a typical vehicle computer. Under these conditions the signal frequency must be between 1. Obdii stands for on board diagnostics second generation superseding that of obd1.

This type of maf sensor also has an intake air temperature iat sensor as part of the housing assembly. Although im not going to be going into details about each of the. If the maf is not reading correctly the lh module would adapt and correct the mixture based on o2 sensor reading. This should be the chassis ground for your mass air flow meter, if you have power and ground here, you can move onto the next section of our how to test a mustang maf guide. A completely failed maf sensor will not send any airflow information to the pcm. From the increase in temperature, the ecm knows the egr valve is open and that exhaust gases are flowing. If you need information regarding your vehicle, consult the repair manual for your particular make and model.

This will be easy to spot because the return voltage will be less than 5v or better be. Determine what type of map sensor is installed in your vehiclevoltage or frequency type. Check the vacuum hose attached to the sensor and make sure it is in good condition and free of obstructions. Part 1 vw mass air flow maf sensor test 5 wire type. A bad mass air flow sensor is often the likely culprit if your car isnt running as it should.

Chec the output of the maf sensor while doing a full throttle run in 2nd gear, as shown in figure b. Once in a while we may encounter a total failure of a maf sensor, one that is, perhaps, short circuited or internally open. In modern cars, the only way to test the mass air flow sensor is with a scan tool. Select your year, make, model and engine to find those that fit your vehicle. The air flow sensor maf is located in the intake air stream and measures the mass of air entering the engine. We carry great brands like acdelco, bosch, duralast, hitachi, and more. Bosch hfm6 digital air flow meters can be reliably tested with still air conditions, ignition on, engine off and exhaust extraction systems removed. Cam sensor ckp crank sensor cmp air flow sensors ammmaf engine coolant sensor ect throttle position switch tps heated oxygen sensors hego accelerator position app map sensor map knock sensor ks exhaust gas temperature fuel temperature sensor egr position sensor inputs ignition coils idle speed control valve iscv. Trouble codes p0171 system too lean bank 1 and p0174 system too lean bank 2 are also often caused by a bad or contaminated mass air flow sensor. How to test a mass air flow maf sensor without a wiring.

A mass air flow maf sensor responds to the amount of air flowing through a chamber containing the sensor. Jan 17, 2019 some vehicles come equipped with both a map and maf sensor, usually forced induction systems like turbocharged and supercharged models. If the specified value is obtained but dtc memory has a dtc concerning mass air flow maf sensor, check the voltage supply of. Download it once and read it on your kindle device, pc, phones or tablets. Here is a fast and accurate way to track a mafs performance and output to the pcm. Symptoms of a bad or failing mass airflow sensor common signs of problems with a mass airflow sensor include running rich at idle or lean under load, decrease in fuel efficiency, and rough idles. Now that you have a broad knowledge of how an airflow meter works, you are ready to test the maf sensor. Jul 24, 2016 here is a video on how a mass air flow and a manifold absolute pressure sensor work and also how you can test them using a basic multimeter.

You can get another maf for a small amount of money, but the maf you need is a pierburg and the maf you can get is a bosch. I also show you how you can figure out the wires without a wiring diagram. Mar 22, 2010 the most common way to test the 5 wire vw mass air flow maf sensor is just to unplug it with the engine running. Use features like bookmarks, note taking and highlighting while reading automotive sensor testing diagnostic strategies of modern automotive systems book 1. Jul 25, 20 testing to see if the mass air flow maf sensor on your toyota 1.

If for example you have intake air leak the maf no longer measures all air getting into the engine and lh doesnt add fuel to make a correct mixture. On most current vwaudi engines, the actual maf value can be found in group 002, field 4 or group 003, field 2. Jul 20, 2009 a maf sensor can be tested without a scan tool. In addition, to measure inputs and outputs voltage according to the instructions from the above link some modifications of maf s connector are necessary, but i hate to do it. In addition to testing and calibration, another important factor for performance is the use of highquality rtd sensors. A hotwire mass air flow sensor has a small electrically heated wire hot wire. Emulator maf and oxygen sensor sk04a v5 user guide sdsauto. When testing a map sensor, first make a preliminary check. Without appropriate testing, its hard to distinguishjust by drivingamong certain ignition or knock sensor faults and maf sensor malfunctions. How to test a maf or map sensor with a multimeter plus an. The ecm needs to know intake air volume to calculate engine load. Some vehicles use a mass air flow sensor maf instead of a map sensor. Figure 254 typical ignition timing map developed from testing and used by the vehicle computer to provide the. First, open the hood of your vehicle and locate the maf sensor on the air cleaner assembly.

Under these conditions the signal frequency must be. Dtc p0102 mass air flow maf sensor circuit low frequency. This months column started on a simple assumptionthat egr flow could be easily calculated by opening the valve at a constant throttle opening using a bidirectional scanner command, vacuum pump, etc. Delphi has the high quality emissions, ignition and sensor parts to help you keep that pesky check engine light off and keep your customers happy.

The chassis wire is the next wire which is black wire with white stripe. Its always a good idea to test a mass airflow maf sensor before replacing it. Yes, a digital multimeter can be used in testing the mass air flow maf sensor. I actually do not know which pin on maf or on its connector is which, so i can not reliably measure voltage. The sensor for volume consumption of air is used in many systems for management of engines for measuring value of the transitory cost of air. Testing to see if the mass air flow maf sensor on your toyota 1. In this article i am going to briefly explain the three basic multimeter tests that are done to find out if its bad or not. So either the maf sensor on my truck may be faulty, or it is supposed to be tested in a different way. Remember you will be testing the harness side of the maf connector. In my case the third wire of the sensor gives a constant 12.

This is necessary to determine how much fuel to inject, when to ignite the cylinder, and when to shift the transmission. But the real key to testing with a multimeter is the signal return lead. When the oe fails, trust standard comprehensive maf sensor coverage premium quality. Is there anything else i can do to see if this really is the problem. Before replacing the sensor, however, the rest of the circuit should be checked for proper operation. Pdf the experiment work to know locations of mass air flow sensor maf and intake air temperatureiat sensors, and classify its types. Part 1 the basics of testing a mass air flow maf sensor. Mass air flow converters on a rainy monday, when youre late for work, suddenly your tdi looses power. Here is a video on how a mass air flow and a manifold absolute pressure sensor work and also how you can test them using a basic multimeter.

Sometimes, the map sensor is used to monitor egr operation, and doubles as a back up to the maf sensor. If you test the other leads associated with the maf and you see another 5v reference and a return voltage those will be for the intake air temp. Delphi af10043 mass air flow sensor shown delphi quality. If the maf is bad either because its not producing a signal or producing an erratic one, the cars idle will return to normal and the car will seem to run fine. Notice all of the chips,resistors,and capacitors that are used in this computer. When the catalytic converter is working properly the computer sees. Driveability corner egr system maf map motor magazine. It is intended to be insensitive to the density of the air. Before we jump into the diagnostic, lets take a look at how the maf sensor works so the procedure makes sense to you.

The egr temp sensor is connected to the thg terminal on the ecm. Computers and sensors operation,diagnosis, and service. Maf sensor testing the techassist team its always a good idea to test a mass airflow maf sensor before replacing it. Explain in detail the testing procedure of a maf sensor. Explain in detail the constructions and how a vaf vane air flow meter works. If the circuit has an issue, replacing the sensor will not solve your problem. Put a stop to engine hiccups and stabilize your engines airfuel mixture with a new mass air flow sensor maf from autozone. Make sure there are no loose wires and the sensors electrical connector is in good shape. The sensor element and air flow meter body form a calibrated unit and are not interchangeable. The element is cooled as air passes over it, and this information is converted into an electronic pulse to be relayed to the onboard computer. The most common way to test the 5 wire vw mass air flow maf sensor is just to unplug it with the engine running. Assuming this test is done at or near sealevel, the peak output of the sensor in gs should be roughly 80% of the rated horsepower of the engine.