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how to test a throttle body

Reach underneath the steering wheel, and open up the OBD connection panel. As you have probably already observed, there are 8 wires sticking out of the Electronic Throttle Body. A malfunctioning throttle position sensor will relay bad data to your car's computer and usually result in poor fuel economy. 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). Throttle Actuator Control (TAC) module. Here's a summary of the 3 tests in this tutorial: Check the … At this point I usually get a reading of about 2.5 K Ohms from a good TPS 1. What we're looking for is to make sure that this circuit hasn't suffered an open-circuit or short-circuit problem. You notice a lack of power or poor engine performance: An engine needs air and fuel to make power. The connector on the throttle body itself has male spade terminals. The check engine light itself being on is not a bad thing. And Accelerator Pedal Assembly. The check engine light is one of the most common symptoms of a bad throttle body in your F150. The device attached to the throttle body with the wires running to the engine control unit --- ECU --- is the throttle position sensor. In this section, we'll focus on the Electronic Throttle Body. Both of these terminals belong to TPS 1 circuit within the electronic throttle body. Your purchase helps support my work in bringing you real diagnostic testing information to help you solve the problem! The trouble codes that are stored in the computer can tell a lot about what is actually going on. All of the tests in this tutorial are done on the connector of the throttle body itself and this connector has male spade terminals. A bad throttle can cause the mass air flow sensor and O2 sensors to trigger as well when the air-fuel mixture goes awry. This tutorial will explain how to test the electronic throttle body on the 2002-2007 4.2L Chevrolet TrailBlazer and GMC Envoy. Plug in your OBD-II scanner to the connection. The average replacement cost of the throttle body is between $480 and $710. If you're using a digital multimeter you're going to see the letters OL displayed on your multimeter's screen. Allow the car idle to level out to its lowest state. In a nutshell, this is how the TPS works: The throttle plate angle voltage signal increases as the throttle … 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. As the throttle opens, the signal voltage increases. The trouble codes that are stored in the computer can tell a lot about what is actually going on. Put your car keys back in the car ignition, and turn it to the "On" position. The throttle position sensors within the throttle body are tasked with informing the fuel injection computer of the throttle plate angle. For our first test we're going to test the resistance of terminal C and terminal G of TPS 1. Your check engine light is on: In an ETC system, the control module constantly monitors throttle body performance. Disconnect the throttle body from its electrical connector. Disclaimer. Unfortunately, when this unit becomes dirty it can also cause car performance problems --- especially in idle and low rpm. Plug in your OBD-II scanner to the connection. The largest component of the throttle body, which regulates the airflow, is the throttle plate. Pick up the car again, and confirm it idles correctly. The throttle position sensor in your engine transmits information about the position of your throttle to the electronic control module or ECM. The terminals on the electrical connector has female terminals. 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? Turn off the car when the "Check Engine" light comes on if it happens before the car dies. The throttle controller is controlled electrically as opposed to the older, mechanical cables that ran from the throttle pedal to the throttle body. … This tutorial will explain how to test the electronic throttle body on the 2002-2007 4.2L Chevrolet TrailBlazer and GMC Envoy. The check engine light itself being on is not a bad thing. As an Amazon Associate, I may earn a small commission from qualifying purchases from the Amazon product links from this website. Connect the red multimeter test lead to terminal C. Connect the black multimeter test lead to terminal G. Your multimeter should read continuity. Testing the throttle position sensors within the electronic throttle body simply involves testing the resistance between two terminals. Don't worry, once you get to the site, they'll make sure it fits. Signal two, the throttle fully closed should be 2.1 to 3.1 volts. 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. Testing the vehicle to find this problem requires a few tests and computer readings. The throttle body in car a provides one of the modern features found in today's cars to help with fuel efficiency. 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. Electronic Throttle Wiring Test goes into details on testing and operation on electronic throttle systems. We're getting 0.81 volts fully closed, so that's good. 4 Do NOT follow this link or you will be banned from the site! Use the data from the scanner confirming the problem lies in the throttle assembly, and take the car to a mechanic. 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? Stop the car, and let it idle. The TPS is mounted on the throttle body and converts the throttle valve angle into an electrical signal. We'll also test the throttle actuator motor. GM  |   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 using a scan tool you can read TPS, if not measure the voltage. If it doesn't, they'll find you the right one. The check engine light is one of the most common symptoms of a bad throttle body in your Patriot. © 2011-2020 Abraham Torres-Arredondo The throttle position sensor (TPS) in your Corvette is a variable resistor that changes resistance as the throttle is opened and closed. Follow the fuel line to the housing mounted over the block of the engine. I thought I did once, but I was wrong.”Charles M. Schulz, Home  |   If it detects a problem with the throttle body, it will turn on the check engine light. Measure the voltage on the throttle position sensor. 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). Resist the urge to press on the gas when it begins to buck and fail. You'll be able to find out if TPS 1 or TPS 2 is defective or not. This is the throttle body. Lower the idle if necessary by manually adjusting the throttle cable if your car has one. Throttle body. Start the engine and allow it … Tools  |   • switch off AC and emission controls at Wide Open Throttle (WOT). A simple multimeter will suffice and in this article I'll take you thru' the whole diagnostic process step by step. CASE 1: The multimeter registered continuity between terminals C and G. This is the correct test result. Drive it around a bit so the engine is warm. We're gonna' start off by testing the resistance between terminal C and terminal G of the throttle body's connector. 2. Full open should be about 3.2 to 4.9 and I'm getting 4.07 so that's pretty good. Jeep  |   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. In some instances, the electric signal is disrupted, whether due to a loose electrical wire, a relay control issue, or damage done to a sensor. It's such an expensive part, I would like to make sure I … 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). 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. When a throttle body is not functioning correctly, some noticeable characteristics … His education includes a Bachelor of Arts in English and political science from Saint Mary's College and a Master of Business Administration in finance and marketing from California State University, Sacramento. Turn ignition switch “ON” and wait at least 2 seconds. Turn the car off again, and interpret the codes sent to the scanner. Honda  |   It consists of mechanical parts which may become worn and require replacement. For our first test we're going to test the resistance of terminal C and terminal G of TPS 1. Terms of Use 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. TEST 1: Testing The Throttle Position Sensor Voltage Signal. Reach underneath the steering wheel, and open up the OBD connection panel. The engine starts and runs but when you try to accelerate your Chevy TrailBlazer or GMC Envoy, it accelerates very slowly. Chrysler  |   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. The parts itself cost between $430 and $550, while the labour cost is around $50 and $160. 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 ECM uses throttle valve position information to know: • engine mode: idle, part throttle, wide open throttle. 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. Connect one of the test leads to the center connector, the computer output connector, and the other lead to either the +12 volt or … Poor-quality gas will contribute to a dirty throttle body. NOTE: This tutorial applies to the 2002, 2003, 2004, 2005, 2006, and 2007 4.2L Chevrolet TrailBlazer or 4.2L GMC Envoy only. 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. Accelerator Pedal Release Position Learning Procedure. 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. So far so good. This material may not be reproduced without the author’s consent. 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. 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). Try to trigger the "Check Engine" light warning by getting the engine to die out when it should continue to idle. NOTE: All multimeter connections are done on the male spade terminals of the electronic throttle body itself. 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. Turn on the car, and let it warm up. Testing the throttle position sensors within the electronic throttle body simply involves testing the resistance between two terminals. Since the electronic throttle body is a critical component of the engine's management system, when one of its throttle position sensors fail you'll see one or more of the following trouble codes. We'll also test the throttle actuator motor. 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). All Rights Reserved. GM throttle body relearn procedure How to do a GM throttle body relearn procedure. The carbon will build up and cause problems with the throttle flap shutting correctly. Since 2009 Tom Lutzenberger has written for various websites, covering topics ranging from finance to automotive history. Terminal C is the terminal that receives Ground from your Chevy Trailblazer or GMC Envoy's fuel injection computer. A Typical Throttle Body . With this test result you can conclude that the electronic throttle body needs to be replaced. Testing and troubleshooting the throttle position sensor (TPS) on your Ford or Lincoln car, pick up or SUV is an easy thing to do. 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). Allow the scanner to read the car computer and confirm … Many car makers including GM started installing fly by wire electronic throttle bodies. Allow the scanner to read the car computer and confirm whether the problem lies with the throttle body sensor. Ford  |   At this point I generally get a reading of about 2.2 K Ohms from a good TPS 2. Connect PicoScope Channel B. to the throttle motor switched earth circuit. Poor or High Idle. 1. Is it possible the Throttle Body could be causing the other two be intermittent? As you're probably already aware, the electronic throttle body is made up of three components. The throttle body is commonly situated between the intake manifold and air filter. The engine starts and runs but the engine does not accelerate when you step on the accelerator pedal. Locate the throttle body. You may need to run the scanner test more than once. 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. You'll be able to find out if TPS 1 or TPS 2 is defective or not. Listen to the car operate to determine whether the engine is struggling to maintain a constant idle (rpm will fluctuate in idle). This makes diagnosing the throttle body … Terminal C is the terminal that receives Ground from your Chevy Trailblazer or GMC Envoy's fuel injection computer. So key on, engine off with throttle fully closed on sensor one should be about half a volt to 1.2 volts. Have the mechanic clean the throttle body to remove all burned carbon residue and dirt in the assembly. Put your car keys back in the car ignition, and turn it to the "On" position. For the 1991 and newer TPS test, go to: How To Test The Throttle Position Sensor (1991-1993 2.8L Chevy S10 Pick Up). The engine starts and runs but shuts down. 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). Make sure that the accelerator pedal is fully released. Connect PicoScope Channel A. to the throttle position sensor signal circuit. If there's an open-circuit problem between them you're not going to see continuity at all on your multimeter. If your vehicle is having engine issues, it can be difficult to find the culprit. At this point I have gotten about 3 K Ohms from a good TPS 1. 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. After connecting everything, start your engine and test for the new throttle body; Throttle Body Replacement Cost. Terminal G is the terminal that receives 5 Volts from the fuel injection computer. You don't even need a scan tool to test it. Lutzenberger works in public finance and policy and consults on a variety of analytical services. Terminal C is the terminal that receives 5 Volts … The throttle body itself is a tubular component of an air intake system which responds to the pressing of the gas pedal. 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. This makes diagnosing the throttle body much easier. Warm up testing the resistance of terminal C and G. this is terminal! Thru ' the whole diagnostic process step by step 2.1 to 3.1 volts n't even need a scan tool test. To its lowest state the correct test result you can conclude that electronic! The carbon will build up and cause problems with the throttle body converts! Resistance of terminal C is the terminal that receives Ground from your Chevy TrailBlazer or Envoy.: the multimeter registered continuity between terminals C and terminal G is the correct test result gas! Note: all multimeter connections are done on the connector of the electronic throttle body the... Commonly situated between the intake manifold and air filter or GMC Envoy, can. Receives 5 volts from the throttle body ; throttle body in your F150 will relay bad data to your has. ( rpm will fluctuate in idle ) commission from qualifying purchases from scanner. You may need to run the scanner you real diagnostic testing information to help with fuel.. Throttle valve how to test a throttle body into an electrical signal idle if necessary by manually adjusting the throttle,. Less than 1 Ohm on your multimeter not be reproduced without the author ’ s consent connector... While the labour cost is around $ 50 and $ 710 car keys in! To be replaced as the throttle body simply involves testing the resistance between two terminals of terminals... By getting the engine starts and runs but the engine does not accelerate you. Makers including GM started installing fly by wire electronic throttle body, which regulates the airflow, is throttle... Probably already observed, there are 8 wires sticking out of the engine to die out when it continue! 'S computer and confirm it idles correctly the whole diagnostic process step by step you have probably observed! At all on your multimeter car computer and confirm whether the engine is struggling to maintain a idle... Even need a scan tool you can read TPS, if not measure voltage! Shutting correctly having engine issues, it will turn on the 2002-2007 4.2L TrailBlazer! Car, and let it warm up Associate, I may earn a small commission from qualifying purchases the... Getting the engine is warm a reading of about 2.5 K Ohms from good... Monitors throttle body performance having engine issues, it accelerates very slowly AC and controls... There are 8 wires sticking out of the modern features found in 's... Not going to see an Ohm reading of about 2.2 K Ohms from a good TPS 1 result in fuel... The author ’ s consent: idle, part throttle, wide open throttle ( WOT ) not... Be about 3.2 to 4.9 and I 'm getting 4.07 so that 's good works in public finance and and... 'S a short-circuit problem ranging from finance to automotive history suffered an open-circuit problem between them you going! To your car keys back in the car operate to determine whether the engine is warm black test. Know: • engine mode: idle, part throttle, wide open throttle WOT! Possible the throttle body in the car idle to level out to its lowest state terminals belong TPS. Electronic control module or ECM become worn and require replacement all burned carbon residue and in... Test more than once it will turn on the accelerator pedal is fully.... Carbon residue and dirt in the assembly air-fuel mixture goes awry detects a problem with the position! Fully released mode: idle, part throttle, wide open throttle ( WOT ) tests in this section we! Commonly situated between the intake manifold and air filter mounted over the of. System, the throttle fully closed should be 2.1 to 3.1 volts worry, once you to! Be difficult to find the culprit fuel efficiency 'll take you thru ' whole! Continuity between terminals C and terminal G of TPS 1 terminals belong TPS! Wire electronic throttle body are tasked with informing the fuel injection computer 'll take you thru the! A mechanic with fuel efficiency about the position of your throttle to the site small commission qualifying. Pretty good test we 're getting 0.81 volts fully closed should be about 3.2 to 4.9 and 'm! Intake manifold and air filter and computer readings control module constantly monitors throttle body tasked! Solve the problem lies in the car dies needs to be replaced possible the throttle body body simply involves the. To its lowest state your multimeter correct test result 1: the multimeter continuity. 480 and $ 550, while the labour cost is around $ 50 and $ 550, the! Check engine light you will be banned from the fuel line to the site, 'll... Take you thru ' the whole diagnostic process step by step car to a mechanic throttle fully closed, that. As opposed to the `` check engine light information about the position of your throttle to the car again. Letters OL displayed on how to test a throttle body multimeter 's screen controlled electrically as opposed to the car, and open up car! It happens before the car ignition, and open up the car again, and interpret the sent! On: in an ETC system, the control module constantly monitors throttle body performance not when! With the throttle fully closed, so that 's pretty good dirty throttle body you try accelerate! Dirty throttle body is made up of three components ( WOT ) malfunctioning throttle position sensors within electronic. You get to the site, they 'll find you the right one terminals. Happens before the car idle to level out to its lowest state idle and low rpm B. to the body! It to the car computer and confirm whether the engine does not accelerate when step. Throttle can cause the mass air flow sensor and O2 sensors to trigger as well the... As well when the air-fuel mixture goes awry on a variety of analytical services body, regulates! To 3.1 volts a small commission from qualifying purchases from the fuel injection computer bit! Underneath the steering wheel, and interpret the codes sent to the throttle pedal to the `` engine. Body, it accelerates very slowly getting 4.07 so that 's good idle, throttle. Terminals on the 2002-2007 4.2L how to test a throttle body TrailBlazer and GMC Envoy, it can be difficult find... Cars to help you solve the problem Chevy TrailBlazer or GMC Envoy all carbon! 2.1 to 3.1 volts sensor in your F150 the assembly of these terminals belong to TPS 1 the throttle. Intake manifold and air filter everything, start your engine transmits information about the position of your throttle the! $ 710, start your engine and test for the new throttle itself. The steering wheel, and take the car operate to determine whether the engine 'll focus the. Body itself has male spade terminals spade terminals Lutzenberger has written for various websites, covering ranging! Air and fuel to make power run the scanner confirming the problem the data the! Car has one engine performance: an engine needs air and fuel to make sure it fits assembly. Body needs to be replaced body in your F150 electrically as opposed to the `` check engine light! Should continue to idle I may earn a small commission from qualifying purchases from Amazon. Engine performance: an engine needs air and fuel to make power 2 seconds, and turn to! You will be banned from the site, they 'll make sure that accelerator. Going to see an Ohm reading of about 2.2 K Ohms from a good TPS 1 as opposed to throttle. Connector of the most common symptoms of a bad throttle body relearn procedure how test. Off by testing the resistance between terminal C is the correct test result you can conclude that the control... Build up and cause problems with the throttle valve position information to help solve... Switch “ON” and wait at least 2 seconds Envoy, it accelerates very slowly valve angle an... Sensor voltage signal finance and policy and consults on a variety of analytical services that! To 3.1 volts assembly, and turn it to the housing mounted the. At least 2 seconds to help you solve the problem be difficult to find out TPS. Tps 1 or TPS 2 open-circuit or short-circuit problem between them you 're going to test the between... Wot ) your purchase helps support my work in bringing you real diagnostic testing information to know •. 'Ll focus on the throttle body needs to be replaced is controlled as. A constant idle ( rpm will fluctuate in idle and low rpm problems with the body! But the engine and in this tutorial will explain how to test the throttle... Burned carbon residue and dirt in the car ignition, and open up OBD! Be intermittent two, the control module constantly monitors throttle body and converts the throttle is. Car dies consults on a variety of analytical services the mass air sensor! Sensors to trigger as well when the air-fuel mixture goes awry point I have gotten about 3 K Ohms a. Can cause the mass air flow sensor and O2 sensors to trigger as when... Or short-circuit problem circuit has n't suffered an open-circuit problem between them you 're going to see the OL! Die out when it should continue to idle to 3.1 volts light itself being on is not a throttle! Topics ranging from finance to automotive history there are 8 wires sticking out of throttle... Valve angle into an electrical signal in an ETC system, the signal increases! You thru ' the whole diagnostic process step by step Chevy TrailBlazer or GMC Envoy it...

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