What Do You Do With the Sensor Hookups After Cold Air Intake Install 1997 Audi A4 1.8t

Dan Ferrell writes nigh do-it-yourself car maintenance and repair. He has certifications in automation and control applied science.

Yous might exist thinking of installing a new mass airflow (MAF) sensor to see if it'll fix your engine driveability problems. But it'south not a good diagnostic approach to merely supersede the sensor without investigating. You can spend $100 or more on a quality airflow sensor and all the same solve nothing. But you lot can learn how to troubleshoot a MAF sensor in a few steps following this simple guide.

Hither, yous'll encounter:

• the most mutual problem affecting MAF sensors (and what to practice about information technology),
• how to notice out whether you are dealing with a bad sensor,
• and what you need to pay attention to during your troubleshooting process.

Topics in This Article

1. Symptoms of a Bad MAF Sensor

2. How the MAF Operates

3. Troubleshooting a Mass Airflow Sensor

• A) How to Test the MAF Circuit for Power and Basis Signals
• B) How to Test the MAF Sensing Element for Continuity
• C) How to Examination MAF Sensor Voltage Signals

four. MAF Sensor Examination Results

5. How to Install a New MAF Sensor

i. Symptoms of a Bad MAF Sensor

You may have a bad MAF sensor if you observe one or more than of the post-obit symptoms:

• A decrease in engine power
• The engine vibrates (poor idling)
• The engine hesitates or stalls at dispatch
• More frequent stops at the gas station
• The engine surges at idling
• Other driveability bug
• You get diagnostic problem codes pointing to the MAF sensor

On some vehicle models, the MAF sensor also informs the estimator about air intake temperature and engine load (to control some automated transmission functions). So a bad MAF sensor on these cars can crusade an fifty-fifty wider range of symptoms.

You tin can hardly diagnose a MAF sensor on symptoms lonely. Other faulty components, like the fuel pump, fuel pressure regulator, and vacuum system, tin can create similar symptoms. That's why you need to troubleshoot the MAF sensor (and related circuits as needed) before replacing components.

2. How the MAF Works

Before we jump into the diagnostic, allow's accept a expect at how the MAF sensor works and then the process makes sense to you.

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 torso.

Depending on the brand and model, your car uses either a hot-wire airflow meter (the near common) or a hot-film type. Different pattern, same function: it tells the computer how much air is flowing into the engine. The computer uses this data, along with input from other sensors, to provide the correct amount of fuel to the engine at any given time.

The hot-wire type sensor maintains a wire (located in the middle of the airstream) at a college temperature than the air flowing in. To maintain this predetermined temperature, electric current to the wire increases as airflow increases.

In general, the hot-pic type sensor works the aforementioned way except it uses a film instead of a wire to send the signal to the computer.

Information technology is this extra amount of current the sensor is using that tells the computer how much air is flowing in. In other words, the faster you lot drive, the college the cooling outcome on the hot wire or movie, and and then the more current flowing to the sensing element.

So y'all can utilize the sensor operating logic to bear your tests.

Here, nosotros'll go over the steps you demand to troubleshoot a hot-wire type MAF sensor using a digital multimeter (DMM) to read the voltage signals. Testing a motion-picture show-blazon sensor is no different, except that you cheque for frequency signals instead of voltage. For this, you lot'll need a digital multimeter (DMM) or an oscilloscope that can read frequencies. Other than that, the next steps apply.

Read More than from AxleAddict

Use a DMM with at to the lowest degree ten Megaohm of impedance.

Photo courtesy of Alper Çuğun on Flickr.

3. Troubleshooting a Mass Airflow Sensor

Now that you accept a wide cognition of how an airflow meter works, you are ready to test the MAF sensor. Let'due south get set up.

1. First, open the hood of your vehicle and locate the MAF sensor on the air cleaner assembly. Usually, you'll find it betwixt the air filter housing and throttle body. This could be a small block or a cylindrical section mounted as part of the air duct. On some models, you'll find it within the filter housing.
2. Wait for an electrical connector on the air duct right subsequently the air filter housing. If yous have difficulty locating the sensor, wait it upward in the vehicle repair transmission for your particular vehicle brand and model.
3. To test the MAF sensor, you'll need to have the electric connector plugged in to the sensor. So check if you tin can backprobe the wires. If not, yous'll demand to pierce the wires using a pivot when conducting your tests. If you lot use the later method, wrap the pierced wires with electrical tape when you're done with the tests, to prevent rust from creeping into the wires.
4. Place the power, basis(s), and indicate wires on the electric connector. Bank check your repair transmission, ask at your local motorcar parts store, or search online for this information. Sometimes, you can identify these wires by testing them as described later. And so even if yous don't accept this information at hand, get alee with the tests anyway.

Now, nosotros'll look at the steps to test a hot-wire type MAF sensor using a digital multimeter by reading its voltage signals. Remember that testing a hot-film blazon sensor is basically the same except you are reading frequency (Hz) signals rather than voltage. If you don't know what blazon of sensor you have on your vehicle, consult your vehicle repair transmission, ask at your local motorcar parts store, or search online for the MAF sensor for your detail vehicle make and model and read through the clarification.

Circumspection - Can You Cause Electrical Damage With Your DMM?

Yep, you can. When troubleshooting electronic car components with a digital multimeter, e'er employ one with at to the lowest degree 10 Megaohm impedance protection. This prevents the meter from drawing too much current and destroying sensitive electronic devices.

A) How to Test the MAF Circuit for Power and Footing Signals

Hither, you bank check that your machine reckoner is actually sending power to the airflow meter and grounding the circuit.

1. Unplug the MAF electrical connector. Visually inspect the electrical connector and terminal for dirt or damage. Gently pull on the wires to bank check for tightness. A dirty, burnt, contaminated, or loose wire will interfere with the sensor signals.
2. Set your digital meter at or close to 20 Volts DC (direct current).
3. Connect your meter's red probe to the connector power terminal (on the side going to the calculator) and the meter's black probe to ground (this could be on the engine block, an unpainted bracket or the negative (black) terminal on your car battery).
4. Turn the ignition key to the ON position, but don't outset the engine.
5. Your meter should read between 10 and thirteen volts, close to battery voltage. If not, you may take a fault in that part of the circuit betwixt the electrical connector and the machine computer.
6. Now, connect your meter's blackness probe to the ground on the connector terminal (on the side going to the computer) and the meter'south reddish probe to the battery'south positive (+) last.
7. Your meter should read betwixt ten and 13 volts, close to battery voltage. If not, you may have a error in that part of the circuit between the electrical connector and the automobile estimator.
8. Turn off the ignition cardinal.

B) How to Test the MAF Sensing Element for Continuity

1. Now, identify the terminals on the MAF sensor itself that stand for to the point wire and basis.
2. Set your meter to "continuity" or the lowest setting on the Ohms calibration.
3. Connect one meter probe to signal and the other probe to ground on the MAF electrical connector; polarity doesn't matter here.
4. Y'all should read 0 (or close to 0) Ohms of resistance. If your meter reads space resistance, probably the MAF sensing chemical element is burnt or broken. Visually inspect the sensor.

C) How to Examination the MAF Sensor Voltage Signals

1. Plug the MAF electrical connector back in.
2. Fix your meter at or close to 10 V DC.
3. Start the engine and let information technology idle.
4. Backprobe the signal and footing wires (red probe to signal and black probe to ground).
5. Depending on your MAF sensor, your voltage reading should be between 0.60 to 0.eighty volts at idle. If your reading indicates 12 volts or pretty close to it, you are probing the ability wire, not the betoken wire).
6. Increment engine speed between ii,500 and iii,500 RPMs by manually opening the throttle plate, or ask an assistant to depress the accelerator pedal. Your voltage should increment to about i.v to 3.0 volts. Recollect that increasing the engine speed increases airflow.
7. On a slice of paper, jot down your voltage readings. Also, notation whether the signal jumped, skipped, responded slowly to increased engine speed, or responded apace and smoothly. Head over to the Results sections below.

A bad MAF sensor may crusade the engine to stall.

Photo courtesy of Konz Ortiz Luis on Flickr.

iv. Interpreting the Results of Your MAF Sensor Test

Now, compare the results of your voltage (or frequency) readings to the specifications in your vehicle repair manual.

If the MAF Sensor Responds Slowly or Not at All

Usually, a slow response, or no response, from the MAF sensor ways one of three things:

• The MAF sensor has failed.
• The hot wire or film chemical element is muddied or damaged so that it is unable to 'feel' air flow.
• The sensor self-cleaning electrical circuit (on hot-wire types) has failed.

The most mutual cause of MAF sensor failure is a dirty sensing element.

Depending on your specific results, you may want to check the sensor itself:

1. Disconnect the MAF sensor from the air cleaner assembly and visually inspect the sensing element.
2. If the sensing element is dirty, the sensor might actually exist working merely contamination is preventing it from doing its task.

Hot-wire blazon sensors have a self-cleaning electric circuit that heats the sensing chemical element up to 1000 C degrees (1832 F) when you shut off the engine. If that part of the circuit fails (not uncommon), the sensor volition end up covered in dirt and eventually fail to read incoming air. A quick check is to take a await at the excursion fuse and and so examination the relay that controls the self-cleaning circuit. Apply this guide How to Test a Fuel Pump Relay and Other Automotive Relays to check the relay in the circuit. If necessary, consult your vehicle repair manual to locate the relay.

Too, you may desire to try cleaning the sensing element with MAF sensor cleaning spray. Avoid touching the sensing element, and never make clean a sensing element with a rag or cleaners not intended for a MAF sensor or electrical contacts. Follow the product manufacturer instructions, and retest the MAF sensor following the previous steps.

If Cleaning the MAF Sensor Solves the Problem

If cleaning the MAF sensor with the cleaning solution solves the problem, and then:

• Yous may have a problem with the self-cleaning circuit
• An air leak around the cleaning assembly is bypassing the air filter.
• A low-quality filter is shedding fabric and sticking to the sensing element.
• An air leak around the air filter housing (a crack on the filter housing or improperly installed filter cover or loose clamps) is introducing unfiltered air and contaminating the sensing element.

If Your Tests Don't Find Annihilation Incorrect With the MAF Sensor

If your tests didn't reveal something wrong with the sensor or the circuit, but your computer says at that place's something wrong with it, check the office of the air cleaner assembly between the sensor and the throttle body. Air leaks volition pull a fast one on the reckoner into thinking the sensor has failed.

If Your Results Seem Inconclusive

If you don't know how to interpret your results, cheque with your dealer, or on online machine forums defended to your vehicle make and model for a possible technical service bulletin (TSB) related to your problem. Technical problems with the pattern or materials used in the MAF sensor or circuit tin show up after miles of driving.

5. How to Install a New MAF Sensor

If your tests indicate a bad MAF sensor, you lot can supervene upon information technology yourself in a few minutes. In nearly vehicle models, all you take to practice is:

• Disconnect the function of the air intake duct that connects to the MAF sensor.
• Carefully unplug the sensor electric connector.
• Unscrew ii or more sensor mounting bolts.
• Remove the old sensor.
• Install the new one.

Further Investigation

Most of the time, your test results will lead you to the crusade of the problem in a few minutes. For example, if a sensor fails to reply to an incoming signal, you know that the problem lies with the sensor itself.

Other times, the results may not accept you too far, especially if yous don't have much feel in car repair. When this happens, you can visit 1 or more forums dedicated to your specific vehicle make where you lot tin communicate with other drivers that might've faced this same type of problem.

If your tests prove that your MAF sensor works as expected, perhaps you're dealing with a fuel, ignition, or vacuum-related problem.

Well-nigh of the time, though, you'll be able to detect the cause of the problem, brand the repair, and get your car back on the road sooner than yous thought possible.

This article is authentic and true to the all-time of the writer's cognition. 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: Information technology is true that if yous unplug the MAF sensor and the engine is notwithstanding running and then the sensor is bad?

Answer: Removing the sensor helps to diagnose a bad sensor in some cases. For example, unplugging a bad IAC that is causing a surge in some models, it can change the idle, so you know the solenoid is causing trouble. And some do the same if they are having issues with the MAF. The computer uses a default setting if it doesn't receive the betoken. Merely information technology's better to troubleshoot the sensor, you may have a bad connector or wire, earlier replacing it.

Question: If I forgot to disconnect the battery and I plugged the MAF, how I tin can remove the notification of the check engine?

Answer: Brand sure the sensor is properly connected. Sometimes the light volition reset itself. An auto parts store tin can cheque the code(s) and reset the light for you.

Question: when I connect my connector, the car shuts off. When I unplug it, information technology stays on only won't drive that fast. What's the problem, the connector or sensor?

Answer: Most likely, the MAF sensor is bad.

Question: I have a 2012 Chevy Malibu. Information technology will not beginning. I disconnected the mass air period sensor, now information technology acts like it wants to outset. Could the mass airflow sensor exist the problem?

Reply: It's possible. Download trouble codes and see if you go any. Faulty camshaft and crankshaft sensor produce the same symptom.

Question: What does information technology mean when the MAF sensor on my 1996 Chevy Tahoe has i.23 ohms of resistance?

Reply: Reading some resistance on the signal path in the sensor means there'due south some "interference" against the current. This may indicate a damaged or partially burned element.

Question: Can I reuse bolts to mass air flow sensor when replacing it with a new one?

Answer: Yes you can, if they're practiced.

Question: On 2009 Mazda CX-7 if MAF sensor has been replaced twice with OEM part and it fails the next forenoon. What should I wait for?

Answer: Troubleshoot the sensor and see if the sensor itself is failing. There could exist a trouble in the circuit, bad connector or loose wire. Besides, check for a possible vacuum leak, specially betwixt the sensor and throttle torso.

Question: My check engine low-cal is on. I cleaned the MAF sensor and reset past unplugging the battery simply it came on once again. The car is running normally. It continues to run even when I unplug the connection to MAF sensor. What could exist wrong?

Answer: Endeavor erasing the trouble code with a scanner tool. If the MAF sensor or its excursion is faulty, unplugging the sensor will cause the reckoner to run with pre-programmed parameter (approximate) until you fix or replace the sensor with a proficient unit.

Question: I just put a new sensor on my Lexus 2001 es300, and when I drive my motorcar around the corner, it still dies out. What could it be?

Answer: It's hard to tell. If it but happens when turning around a corner, look for a loose wire (possibly an ignition system wire - nether the dash?), or a fuel pump issue. Check for problem codes and see if you discover annihilation.

Question: Volition my automobile run if the mass airflow sensor is disconnected?

Answer: Information technology may run. If disconnecting the MAF sensor makes a possible engine problem go away, cheque the cam and cranks sensors and fuel pressure.

Question: I have replaced my MAF sensor three times. Last 1 is an AC Delco unit of measurement. Bold that the MAF sensor is working correctly and sending information to the ECM, could the ECM be malfunctioning and causing the signal information to get distorted or misread? What else could cause outside ambient temps to be off?

Answer: There's a possibility that the ECM be malfunctioning, only is not that common. If you changed the MAF because a DTC, check the input and output voltages (incoming and outgoing) from the sensor. The trouble could be in the circuit itself, the connector or a wire.

Question: I installed a new MAF sensor, but the motorcar won't even idle. What is the crusade?

Reply: If the auto was idling with the onetime MAF sensor, disconnect the new sensor and check if the engine idles. If it does, either the new 1 is faulty or possibly there'due south something wrong with the circuit.

Question: Do I accept to disconnect the battery before the MAF sensor is replaced?

Answer: No. But make sure not to leave air leaks when putting back the air cleaner assembly or you'll create a fault and crusade bad engine performance.

Question: Isn't a mass airflow sensor supposed to have a certain resistance between the indicate and the ground on the sensor itself? I go about viii.8k ohm on mine. What could cause that much resistance?

Reply: It depends on your awarding--meet your vehicle repair manual. On some models, swinging the sensor'south plate period should produce a smooth increase in resistance.

Question: I'm non getting enough voltage getting to MAF sensor. Whatever ideas?

Respond: If you are getting some voltage, in that location could be a bad connector or loose wire. Bank check the terminals for a loose wire or bad connectedness.

Question: My mass air flow sensor on an 88 Camaro 2.8 reads 5-volt reference between signal and ground while running and unplugged, on the ECM side, at idle. Shouldn't the mass air menses sensor dictate the voltage going out to the ECM? While plugged in, in that location is erratic non-detectable voltage, on/off, on/off. My ground tests practiced, and I have fantabulous battery voltage on ECM side of the harness. I get the same effect with two mass air menstruum sensors.

Answer: Cheque the connectors and wires for loose or damage issues.

Question: When I unplug my MAF sensor, motorcar shakes for 1-2 seconds and and then starts normally. I try to drive it with the MAF sensor and unplugged it seems to operate similar normal. 2009 BMW 525I 3.0L. I have a trouble when it's cold. It has a rough starting simply after 2 minutes, when information technology gets warmer, it's good. What could be the trouble with my car'southward MAF sensor?

Answer: This could be from a faulty sensor, an engine coolant temperature sensor, for case. Download trouble codes from the reckoner memory, even if you don't meet the engine low-cal coming on. There could be a awaiting code. Besides, endeavour cleaning the MAF sensor. This is a common result. This post may assist:

https://axleaddict.com/auto-repair/How-to-Make clean-a-...

Question: What does it hateful if, when back probing to exam for voltage bespeak, the engine dies? At present, when turning the key to starting time, only power comes on and the starter does not creepo. Do you have whatever clues to where the starter relay is located on a 1991 Park Avenue?

Respond: Check the battery connections and make sure voltage is reaching the starter relay. Y'all may want to practice a voltage driblet on the starting system circuit. This other post may assist:

https://axleaddict.com/auto-repair/Automotive-Volt...

I believe in your model the starter relay is located towards the firewall. Look to the left of the steering cavalcade. You lot'll see the relay.

Question: I have an A4 Audi sedan 1.8. If I replace the airflow sensor with a new one, do I have to diagnose the car if I supplant the new 1 with the sometime one once more?

Answer: Y'all might desire to examination the old sensor and see if it actually failed. Sometimes a clogged air filter or air leak in the ductwork can make a adept MAF look bad. You lot can follow the procedure in the post or the 1 in your repair manual. It'due south not a difficult procedure.

Question: My Volvo V50 runs well but and so of a sudden will lose power. Sometimes it helps to milk shake the MAF connector but non always. Is it definitely a trouble with the contacts or it can be something else?

Answer: Check the sensor chemical element for contamination and then troubleshoot it. Take a adept look at the connectors and wires, possibly a loose wire that reconnects when you milk shake it.

Question: I accept Hyundai i20 diesel one.4 variant. Recently, the check engine light appeared in ODO meter. Then I checked it with the OBD2 tool. I got the error code P0103, which indicates MAF sensor circuit high input. What solution will piece of work?

Answer: Test the sensor itself, its voltage output and for a poor connection. These are the about common causes for this code.

Question: When I tested my MAF sensor with a DMM information technology read weird. The DC voltage was set on 20, which was closest to 10. Mine would go the MAF sensor and went up to 2.49 at idle very quickly. With the engine at 2500 to 3000 rpm, it was reading 2.45 and information technology got to that quickly. Does that mean it'south bad?

Answer: Not necessarily. Check your codes and run across if it indicates issues with the circuit. If your DMM has Hz frequency - usually you'll go near 30 Hz at idle and will increase as y'all open up the throttle.

Question: Exercise I have to reset my computer subsequently replacing the mass air menstruum sensor and throttle torso?

Answer: Not necessarily. You may desire to clear the codes, and there could be a reset/relearn procedure for the ECU. Consult your vehicle repair manual. If yous don't have i, your local library may have a copy.

Question: Does the ability wire to the MAF take to be the aforementioned gauge?

Answer: Yes, don't employ a smaller one.

Question: I am in Nigeria, and I need an AIRFLOW METER for a 1996 Nissan Maxima. Delight, how can I get a practiced new one from a reputable function dealer?

Answer: Y'all can contact your nearest Nissan dealer and order the part through the service department. That way you'll be sure you are installing an OEM part.

Question: I cleaned the MAF sensor with the cleaner. It ran a little better, but still crappily. Should I supervene upon my MAF sensor?

Answer: Double-check there are no air leaks between the MAF sensor and the throttle trunk. Air ducts should be properly connected and not damaged. An air or vacuum leak can confuse the computer virtually air book. If possible, test the sensor before replacing it. You want to make sure yous are dealing with a faulty sensor.

Question: The point from MAF is reading two.49-2.51v at idle and accelerating up to 2000-3000 rpm voltage, but non irresolute. Does this hateful the MAF has failed?

Answer: Clean the sensor with MAF sensor cleaner. It'southward possible the sensor is muddied and messing the scale.

Question: 1990 Mazda Miata has major take off bug. How do I go about testing the MAD on the car?

Respond: The best way is to follow the procedure in the repair manual for your detail model. You may be able to find a copy in your local car parts store or online.

Question: P0102 engine code, rough idle, rough acceleration. Replaced mass airflow and won't idle or run. What could be the problem?

Answer: The source for the code may point to different things like the MAF excursion or electrical connector or vacuum leaks. Unplug the MAF sensor and try starting the engine. If you notice something different, the problem may exist in the wiring. Check the circuit voltages using your repair manual. Too, check for a vacuum leak, including the hose between the MAF sensor and the throttle trunk. Hope this helps.

Question: How practise you read airflow meter wires?

Answer: Employ a digital multimeter and follow the instructions in the second section of this post.

Question: I got a 2006 Subaru Liberty that has no air sensor. How do I go past this?

Answer: If the sensor is missing, take it installed.

Question: How tin I fix the idle air control valve?

Answer: Usually you lot can remove the valve and clean any buildup out of the valve and throttle body. If the valve itself is bad, replace it.

Question: Recently tested my MAF sensor and every thing looks fine. The voltage increases as the RPM increment and decreases as the RPM decreases. But when knocking on the sensor, the motorcar struggles to idle normal or some times dies. What seems to be the trouble?

Answer: There could exist a broken wire in the sensor's circuitry. If lightly tapping the sensor changes the idle, the sensor is likely bad.

Question: What would cause MAF sensor output voltage go negative at times?

Answer: Sometimes this blazon of negative output comes from a faulty sensor; cheque for possible awaiting problem codes (no check engine light) that might confirm this.

Question: Will a bad mass airflow sensor crusade your battery to die?

Answer: No. A dead dead bombardment is normally acquired past a faulty battery, bad alternator or circuit or a parasitic draw. This other mail service may help:

https://axleaddict.com/auto-repair/motorcar-batterydrai...

Question: I have a '98 Nissan Maxima. I replaced the scroll, cam sensor, creepo sensors, fuel pump, MAF sensor. What's wrong?

Answer: Fifty-fifty if the check engine low-cal is not on, download DTCs for possible awaiting codes. If you know you are getting expert spark and proper fuel pressure, these other posts might help:

https://axleaddict.com/auto-repair/My-Engine-Crank...

https://axleaddict.com/auto-repair/bad_starter_sym...

https://axleaddict.com/auto-repair/My-Car-Wont-Tur...

https://axleaddict.com/auto-repair/How-to-Use-Volt...

Question: 2014 Ford F150 cranks but won't get-go; it seems like an intermittent problem. No codes are being given. The reckoner was replaced and it happened again. Information technology has been going on for the past calendar week. I'g being advised to supercede the MAF and Fuel Module Associates. I was told it is one or the other. Any thoughts?

Answer: This type of intermittent problem commonly points to electrical faults. A sensor might not be able to ship the correct signal when the fault is there. Check the circuit (wires, connector, harness) for those sensors the estimator depends on to manage fuel, and ignition timing. This could exist the camshaft and crankshaft position sensor:

https://axleaddict.com/auto-repair/How-to-Test-a-C...

throttle position sensor:

https://axleaddict.com/machine-repair/How-Practice-You lot-Know...

or ignition control module.

Bank check the MAF sensor and excursion, if necessary:

https://axleaddict.com/machine-repair/How-to-Test-a-M...

Question: I added a new MAF to my Nissan Titan 2004. Everything came out great. The only problem I accept now is that when I press the gas, the engine sounds like it is releasing air from the pinnacle. What could be the issue?

Respond: There could be a vacuum leak, just this would make the engine run rough. Make sure the air ducts are properly connected, there might be some air being sucked when the throttle opens -- sort of like a bypass.

Question: Does the Scion Xb 2008 2.four liter accept a Maf sensor fuse ?

Answer: Bank check under the power box lid or the fuse box inside the cabin. There should indicate the excursion fuses.

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What Do You Do With the Sensor Hookups After Cold Air Intake Install 1997 Audi A4 1.8t

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