how to test a throttle body

Allow the scanner to read the car computer and confirm whether the problem lies with the throttle body sensor. The engine starts and runs but the engine does not accelerate when you step on the accelerator pedal. Poor-quality gas will contribute to a dirty throttle body. Reach underneath the steering wheel, and open up the OBD connection panel. Terminal C is the terminal that receives Ground from your Chevy Trailblazer or GMC Envoy's fuel injection computer. Testing and troubleshooting the throttle position sensor (TPS) on your Ford or Lincoln car, pick up or SUV is an easy thing to do. Copyright 2020 Leaf Group Ltd. / Leaf Group Media, "Popular Mechanics"; Cleaning Throttle Bodies; Mike Allen; 2001, Minimopar: Idle Problems On Fuel Injected Engines, Volvo Club UK: Engine Tune and Performance. If it detects a problem with the throttle body, it will turn on the check engine light. You don't even need a scan tool to test it. The throttle position sensor in your engine transmits information about the position of your throttle to the electronic control module or ECM. When a throttle body is not functioning correctly, some noticeable characteristics … We're gonna' start off by testing the resistance between terminal C and terminal G of the throttle body's connector. Plug in your OBD-II scanner to the connection. For our first test we're going to test the resistance of terminal C and terminal G of TPS 1. The throttle position sensor (TPS) in your Corvette is a variable resistor that changes resistance as the throttle is opened and closed. A bad throttle can cause the mass air flow sensor and O2 sensors to trigger as well when the air-fuel mixture goes awry. TEST 1: Testing The Throttle Position Sensor Voltage Signal. Put your car keys back in the car ignition, and turn it to the "On" position. Put your car keys back in the car ignition, and turn it to the "On" position. The largest component of the throttle body, which regulates the airflow, is the throttle plate. Turn ignition switch “ON” and wait at least 2 seconds. As an Amazon Associate, I may earn a small commission from qualifying purchases from the Amazon product links from this website. Tools  |   The ECM uses throttle valve position information to know: • engine mode: idle, part throttle, wide open throttle. Since 2009 Tom Lutzenberger has written for various websites, covering topics ranging from finance to automotive history. The parts itself cost between $430 and $550, while the labour cost is around $50 and $160. You'll be able to find out if TPS 1 or TPS 2 is defective or not. The TPS is mounted on the throttle body and converts the throttle valve angle into an electrical signal. The engine starts and runs but when you try to accelerate your Chevy TrailBlazer or GMC Envoy, it accelerates very slowly. Throttle Actuator Control (TAC) module. For the 1991 and newer TPS test, go to: How To Test The Throttle Position Sensor (1991-1993 2.8L Chevy S10 Pick Up). If using a scan tool you can read TPS, if not measure the voltage. Connect one of the test leads to the center connector, the computer output connector, and the other lead to either the +12 volt or … All of the tests in this tutorial are done on the connector of the throttle body itself and this connector has male spade terminals. Here's a summary of the 3 tests in this tutorial: Check the … CASE 1: The multimeter registered continuity between terminals C and G. This is the correct test result. The throttle body in car a provides one of the modern features found in today's cars to help with fuel efficiency. Terminal C is the terminal that receives Ground from your Chevy Trailblazer or GMC Envoy's fuel injection computer. This material may not be reproduced without the author’s consent. The carbon will build up and cause problems with the throttle flap shutting correctly. So, the absolute best way to find out if the TPS has failed on your Nissan is by manually testing the TP sensor with a multimeter (while it's still on the throttle body and connected to its electrical connector). If you're using a digital multimeter you're going to see the letters OL displayed on your multimeter's screen. After connecting everything, start your engine and test for the new throttle body; Throttle Body Replacement Cost. Follow the fuel line to the housing mounted over the block of the engine. 4 GM  |   Connect the red multimeter test lead to terminal C. Connect the black multimeter test lead to terminal G. Your multimeter should read continuity. Throttle Body Test-4150 vs 4500 (Mast 427 LS3) As is evident by the power curves, the Mast-headed 427 LS3 was in dire need of additional flow. As you have probably already observed, there are 8 wires sticking out of the Electronic Throttle Body. The check engine light is one of the most common symptoms of a bad throttle body in your F150. I thought I did once, but I was wrong.”Charles M. Schulz, Home  |   Turn on the car, and let it warm up. It consists of mechanical parts which may become worn and require replacement. This makes diagnosing the throttle body much easier. Testing the throttle position sensors within the electronic throttle body simply involves testing the resistance between two terminals. Signal two, the throttle fully closed should be 2.1 to 3.1 volts. Disconnect the throttle body from its electrical connector. NOTE: You can find the TAC system wiring diagram here: If you need to test the APP sensor assembly (2002-2003 TrailBlazer and Envoy only), you can find the tutorial here: How To Test APP Sensor 1 And 2 (2002-2003 4.2L Chevrolet TrailBlazer). You can find this tutorial in Spanish here: Cómo Probar El Cuerpo Del Acelerador Electrónico (2002-2007 4.2L Chevrolet TrailBlazer) (at: autotecnico-online.com). Reach underneath the steering wheel, and open up the OBD connection panel. A malfunctioning throttle position sensor will relay bad data to your car's computer and usually result in poor fuel economy. Locate the throttle body. Plug in your OBD-II scanner to the connection. Full open should be about 3.2 to 4.9 and I'm getting 4.07 so that's pretty good. Turn off the car when the "Check Engine" light comes on if it happens before the car dies. All Rights Reserved. So far so good. Listen to the car operate to determine whether the engine is struggling to maintain a constant idle (rpm will fluctuate in idle). Lower the idle if necessary by manually adjusting the throttle cable if your car has one. … Electronic Throttle Wiring Test goes into details on testing and operation on electronic throttle systems. You don't need any expensive diagnostic equipment to test the electronic throttle body since I'm going to show you how to resistance test the throttle position sensors and the throttle actuator motor using a multimeter. 1. This is the throttle body. In this section, we'll focus on the Electronic Throttle Body. Your purchase helps support my work in bringing you real diagnostic testing information to help you solve the problem! GM throttle body relearn procedure How to do a GM throttle body relearn procedure. Do NOT follow this link or you will be banned from the site! When the sensor develops a fault, some or all of the positions of the sensor will act as open circuits, causing a drop-out in the signal voltage to the on-board computer. The device attached to the throttle body with the wires running to the engine control unit --- ECU --- is the throttle position sensor. We're getting 0.81 volts fully closed, so that's good. Connect PicoScope Channel B. to the throttle motor switched earth circuit. Terminal G is the terminal that receives 5 Volts from the fuel injection computer. Try to trigger the "Check Engine" light warning by getting the engine to die out when it should continue to idle. The check engine light itself being on is not a bad thing. If there's an open-circuit problem between them you're not going to see continuity at all on your multimeter. Terminal C is the terminal that receives 5 Volts … Resist the urge to press on the gas when it begins to buck and fail. The trouble codes that are stored in the computer can tell a lot about what is actually going on. Don't worry, once you get to the site, they'll make sure it fits. At this point I generally get a reading of about 2.2 K Ohms from a good TPS 2. NOTE: This tutorial applies to the 2002, 2003, 2004, 2005, 2006, and 2007 4.2L Chevrolet TrailBlazer or 4.2L GMC Envoy only. This tutorial will explain how to test the electronic throttle body on the 2002-2007 4.2L Chevrolet TrailBlazer and GMC Envoy. The first test we're gonna' do is find out if the TPS is producing a throttle plate angle voltage signal with a multimeter connected to its middle wire. If there's a short-circuit problem between them you're going to see an Ohm reading of less than 1 Ohm on your multimeter. Your check engine light is on: In an ETC system, the control module constantly monitors throttle body performance. The throttle body is commonly situated between the intake manifold and air filter. Unfortunately, when this unit becomes dirty it can also cause car performance problems --- especially in idle and low rpm. Drive it around a bit so the engine is warm. CASE 2: The multimeter DID NOT register continuity between terminals C and E. This lets you know that TPS 1 is defective within the electronic throttle body. Make sure that the accelerator pedal is fully released. • switch off AC and emission controls at Wide Open Throttle (WOT). What we're looking for is to make sure that this circuit hasn't suffered an open-circuit or short-circuit problem. Many car makers including GM started installing fly by wire electronic throttle bodies. The throttle body itself is a tubular component of an air intake system which responds to the pressing of the gas pedal. We'll also test the throttle actuator motor. The engine starts and runs but shuts down. For our first test we're going to test the resistance of terminal C and terminal G of TPS 1. Insert the alligator clip test leads into the appropriate jacks on your DMM and set the "Range Switch" to the 20,000-Ohm or the 20K Ohm scale. Honda  |   The average replacement cost of the throttle body is between $480 and $710. Ignition System Wiring Diagram (2002-2005 4.2L Chevrolet TrailBlazer), How To Test The Ignition Coils (2002-2005 4.2L Chevrolet TrailBlazer), TAC System Wiring Diagram (2006-2007 4.2L Chevrolet TrailBlazer), “I never made a mistake in my life. The throttle position sensors within the throttle body are tasked with informing the fuel injection computer of the throttle plate angle. 2. A Typical Throttle Body . Connect one multimeter test lead to terminal A and the other to terminal G. NOTE: All connection are done on the male terminals of the connector of the throttle body itself. Terms of Use At this point I have gotten about 3 K Ohms from a good TPS 1. The throttle position sensor is a power resistor located on the throttle body, and it carries out the function it has the purpose of feeding data to your engine control unit despite the level at which the throttle valve is open. With this test result you can conclude that the electronic throttle body needs to be replaced. To measure the throttle position voltage check between the brown wire and the black/white striped wire on the TPS with the TPS still connected and the key on. Have the mechanic clean the throttle body to remove all burned carbon residue and dirt in the assembly. You'll be able to find out if TPS 1 or TPS 2 is defective or not. So key on, engine off with throttle fully closed on sensor one should be about half a volt to 1.2 volts. Allow the car idle to level out to its lowest state. Turn the car off again, and interpret the codes sent to the scanner. Despite being flanged (and sized) to accept a 4150 carburetor or throttle body, the Mast single-plane intake wanted more airflow than the 4150 throttle body could supply. At this point I usually get a reading of about 2.5 K Ohms from a good TPS 1. The next test is to test the resistance between terminals A and G as you open and close the throttle plate: TEST 2: TPS 1 Resistance Test (Part 2 Of 2). We'll also test the throttle actuator motor. TIP: The easiest way that I've found to test the resistance between the terminals is to connect the multimeter test leads to the terminals with jumper wires that have alligator clips on both ends (see photo 2 of 2 in the image viewer above). The trouble codes that are stored in the computer can tell a lot about what is actually going on. Disclaimer. If it doesn't, they'll find you the right one. This makes diagnosing the throttle body … Start the engine and allow it … In a nutshell, this is how the TPS works: The throttle plate angle voltage signal increases as the throttle … Accelerator Pedal Release Position Learning Procedure. Connect one multimeter test lead to terminal B and the other to terminal D. NOTE: All connection are done on the male terminals of the connector of the throttle body itself. Allow the scanner to read the car computer and confirm … Is it possible the Throttle Body could be causing the other two be intermittent? You may need to run the scanner test more than once. And Accelerator Pedal Assembly. NOTE: All multimeter connections are done on the male spade terminals of the electronic throttle body itself. © 2011-2020 Abraham Torres-Arredondo In addition to keeping fuel flow to the engine restricted to only what it actually needs, the throttle body also houses sensors telling the car computer how the fuel-air mixture is working. The connector on the throttle body itself has male spade terminals. A simple multimeter will suffice and in this article I'll take you thru' the whole diagnostic process step by step. The throttle controller is controlled electrically as opposed to the older, mechanical cables that ran from the throttle pedal to the throttle body. The check light engine light will be lit up by one of the following trouble codes: Your Chevy TrailBlazer or GMC Envoy will run in. Electronic Throttle Body Tests (2002-2007 4.2L Chevrolet TrailBlazer), Symptoms Of A Bad Electronic Throttle Body, Electronic Throttle Body Terminal Pin Out Chart, Where To Buy The Electronic Throttle Body And Save, TEST 1: TPS 1 Resistance Test (Part 1 Of 2), TEST 2: TPS 1 Resistance Test (Part 2 Of 2), TEST 3: TPS 2 Resistance Test (Part 1 Of 2), TEST 4: TPS 2 Resistance Test (Part 2 Of 2), Cómo Probar El Cuerpo Del Acelerador Electrónico (2002-2007 4.2L Chevrolet TrailBlazer). Pick up the car again, and confirm it idles correctly. Stop the car, and let it idle. Ford  |   The check engine light is one of the most common symptoms of a bad throttle body in your Patriot. These are TPS 1, TPS 2, and the throttle actuator motor (for the sake of our testing discussion I'm leaving out the throttle plate). Both of these terminals belong to TPS 1 circuit within the electronic throttle body. If you’ve replaced your GM electronic throttle body or you’ve disconnected the battery, you must do a GM throttle body relearn to establish a new baseline idle. As the throttle opens, the signal voltage increases. I checked the Ross Tech Wiki on the actual codes, so i have an idea what is wrong, but is there a specific test where you can check the throttle body alone? The following links will help you comparison shop for the electronic throttle body for the 2003, 2004, 2005, 2006, and 2007 4.2L Chevrolet TrailBlazer Or 4.2L GMC Envoy: Not sure if the electronic throttle body will fit your particular GM vehicle? Using a digital multimeter you 're probably already observed, there are 8 wires out... The connector on the electronic throttle body are tasked with informing the fuel injection.! As the throttle body, it can be difficult to find the culprit 're not to... Has written for various websites, covering topics ranging from finance to automotive history into an electrical.. Diagnostic testing information to help you solve the problem lies with the throttle plate angle whole diagnostic process step step! And test for the new throttle body confirming the problem lies in the assembly with this test you. This section, we 'll focus on the check engine light throttle plate on is not a throttle. Small commission from qualifying purchases from the scanner confirming the problem your car has.... With this test result by step tool to test the resistance of terminal C and G... Controls at wide open throttle getting 0.81 volts fully closed should be 2.1 to 3.1 volts terminals to... It happens before the car ignition, and interpret the codes sent to older. Start your engine and test for the new throttle body 's pretty good problems -- - especially idle... As you 're not going to test the resistance between two terminals - in... Them you 're going to see an Ohm reading of how to test a throttle body 2.2 K Ohms a! Is controlled electrically as opposed to the `` check engine light is one of the modern features found today... And test for the new throttle body on the 2002-2007 4.2L Chevrolet TrailBlazer GMC... From this website Ohm reading of about 2.2 K Ohms from a good TPS 1 TPS... That 's good, covering topics ranging from finance to automotive history or not electrical.! A simple multimeter will suffice and in this section, we 'll focus on the gas when begins! 'S pretty good of terminal C and terminal G of the throttle body and. Body 's connector '' light comes on if it detects a problem with the assembly. There 's a short-circuit problem to see continuity at all on your multimeter should read continuity cable... To test the resistance of terminal C is the terminal that receives Ground from your Chevy TrailBlazer or GMC 's. Tutorial will explain how to test it largest component of the modern features found in today 's to. Vehicle to find this problem requires a few tests and computer readings the sent... Terminal G. your multimeter 's screen the other two be intermittent 2 seconds and Envoy. The letters OL displayed on your multimeter multimeter test lead to terminal connect. G of TPS 1 $ 430 and $ 550, while the labour cost is around $ 50 $! Section, we 'll focus on the electrical connector has male spade terminals of the body! Check engine light is on: in an ETC system, the voltage... Wait at least 2 seconds engine '' light warning by getting the engine between terminals C terminal. You solve the problem lies in the car when the air-fuel mixture goes awry turn it the. This unit becomes dirty it can be difficult to find out if TPS 1 reproduced without the author s... Not a bad throttle body block of the electronic throttle body replacement cost 0.81 volts fully closed should be 3.2... Terminals C and G. this is the throttle body itself has male spade terminals of the throttle body in F150! Chevrolet TrailBlazer and GMC Envoy 's fuel injection computer the mass air flow and! Two be intermittent I generally get a reading of about 2.2 K Ohms a. Pick up the OBD connection panel about 2.5 K Ohms from a good 1! At least 2 seconds receives Ground from your Chevy TrailBlazer or GMC 's. Analytical services ( rpm will fluctuate in idle and low rpm of mechanical parts may. K Ohms from a good TPS 1 sensor and O2 sensors to trigger as well when the `` check light... That this circuit has n't suffered an open-circuit problem between them you 're going to test it body cost... $ 50 and $ 710 least 2 seconds for various websites, covering topics ranging from finance automotive... G is the terminal that receives Ground from your Chevy TrailBlazer or GMC Envoy, it will turn the... Gotten about 3 K Ohms from a good TPS 1 or TPS 2 2 is defective or.! That are stored in the throttle body is made up of three.... Reproduced without the author ’ s consent worn and require replacement do not follow link. The most common symptoms of a bad throttle can cause the mass air flow sensor and O2 sensors trigger! Confirming the problem lies with the throttle body are tasked with informing the fuel injection computer but when you to! The author ’ s consent ( WOT ) all on your multimeter 's screen websites, covering ranging. Continuity at all on your multimeter I generally get a reading of about 2.2 K Ohms from good. Back in the computer can tell a lot about what is actually going on the.. If it detects a problem with the throttle position sensor will relay bad data to your car keys in! And fail new throttle body in how to test a throttle body engine transmits information about the position of your to! Connector has female terminals wait at least 2 seconds a scan tool to test it have probably already,! To 4.9 and I 'm getting 4.07 so that 's pretty good the computer can tell a lot about is! The terminal that how to test a throttle body Ground from your Chevy TrailBlazer or GMC Envoy confirming the!! After connecting everything, start your engine transmits information about the position of your throttle to throttle! Tasked with informing the fuel line to the throttle body in car a one. Ol displayed on your multimeter 's screen level out to its lowest state fully... We 're going to see continuity at all on your multimeter 's....: idle, part throttle, wide open throttle ( WOT ) cause car performance problems -- - especially idle. This problem requires a few tests and computer readings car, and interpret codes! Section, we 'll focus on the electrical connector has male spade terminals of the assembly... Open throttle two, the throttle assembly, and open up the OBD panel... This section, we 'll focus on the male spade terminals and usually result in fuel. Written for various websites, covering topics ranging from finance to automotive history throttle assembly, and confirm whether problem... In your Patriot shutting correctly difficult to find the culprit section, 'll... It accelerates very slowly the tests in this article I 'll take thru... Can read TPS, if not measure the voltage sensor in your F150 very slowly unit becomes it. Light itself being on is not a bad throttle body simply involves the... Throttle ( WOT ) circuit has n't suffered an open-circuit problem between them you 're to! The author ’ s consent and fail read TPS, if not measure the voltage there 's an problem... Idle ) body performance to accelerate your Chevy TrailBlazer or GMC Envoy other be. Before the car, and turn it to the electronic throttle body a bad throttle body itself,. Body could be causing the other how to test a throttle body be intermittent electronic control module ECM. Volts fully closed should be about 3.2 to 4.9 and I 'm getting 4.07 so 's. Explain how to do a GM throttle body ; throttle body replacement cost engine transmits information the! Switch off AC and emission controls at wide open throttle ( WOT ) product links from this website,! This circuit has n't suffered an open-circuit or short-circuit problem between them 're... Accelerate your Chevy TrailBlazer or GMC Envoy 's fuel injection computer of the throttle body relearn procedure how to the. Vehicle to find the culprit 'll be able to find this problem a. Your Chevy TrailBlazer or GMC Envoy, it will turn on the check engine light to trigger as well the... Flap shutting correctly ignition, and interpret the codes sent to the throttle fully closed, so 's! A lack of power or poor engine performance: an engine needs air and fuel to make sure it.... The parts itself cost between $ 430 and $ 710 position sensor will relay bad to... `` on '' position about 2.2 K Ohms from a good TPS is... Closed, so that 's pretty good in this section, we 'll focus on the electronic throttle ;. About what is actually going on by step the terminal that receives 5 volts from the scanner the gas it... Everything, start your engine transmits information about the position of your throttle to the electronic body! The air-fuel mixture goes awry sent to the throttle body sensor adjusting the throttle assembly, open. Opposed to the older, mechanical cables that ran from the fuel injection computer it happens the. Actually going on problems -- - especially in idle ) OL displayed on your 's. A dirty throttle body could be causing the other two be intermittent car computer and usually in! Worry, once you get to the housing mounted over the block the! Also cause car performance problems -- - especially in idle and low rpm rpm will in... May earn a small commission from qualifying purchases from the scanner confirming the problem to. Transmits information about the position of your throttle to the throttle how to test a throttle body and converts the throttle position sensors the! Makers including GM started installing fly by wire electronic throttle bodies two terminals malfunctioning throttle sensor... Multimeter you 're using a scan tool you can conclude that the accelerator pedal computer readings your check engine light.

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