{"id":80060,"date":"2023-01-23T23:32:39","date_gmt":"2023-01-24T07:32:39","guid":{"rendered":"https:\/\/blogv2prod.wpenginepowered.com\/blog\/?p=80060"},"modified":"2026-06-19T05:45:30","modified_gmt":"2026-06-19T12:45:30","slug":"p2120-code-throttle-position-sensor-switch-c-circuit-malfunction","status":"publish","type":"post","link":"https:\/\/www.carparts.com\/blog\/p2120-code-throttle-position-sensor-switch-c-circuit-malfunction\/","title":{"rendered":"P2120 Code: Throttle Position Sensor\/Switch C Circuit Malfunction"},"content":{"rendered":"<!DOCTYPE html PUBLIC \"-\/\/W3C\/\/DTD HTML 4.0 Transitional\/\/EN\" \"http:\/\/www.w3.org\/TR\/REC-html40\/loose.dtd\">\n<html><body><span class=\"span-reading-time rt-reading-time\" style=\"display: block;\"><span class=\"rt-label rt-prefix\">Reading Time: <\/span> <span class=\"rt-time\"> 2<\/span> <span class=\"rt-label rt-postfix\">minutes<\/span><\/span><style>.kadence-column80060_dd95ac-1f > .kt-inside-inner-col,.kadence-column80060_dd95ac-1f > .kt-inside-inner-col:before{border-top-left-radius:0px;border-top-right-radius:0px;border-bottom-right-radius:0px;border-bottom-left-radius:0px;}.kadence-column80060_dd95ac-1f > .kt-inside-inner-col{column-gap:var(--global-kb-gap-sm, 1rem);}.kadence-column80060_dd95ac-1f > .kt-inside-inner-col{flex-direction:column;}.kadence-column80060_dd95ac-1f > .kt-inside-inner-col > .aligncenter{width:100%;}.kadence-column80060_dd95ac-1f > .kt-inside-inner-col:before{opacity:0.3;}.kadence-column80060_dd95ac-1f{position:relative;}@media all and (max-width: 1024px){.kadence-column80060_dd95ac-1f > .kt-inside-inner-col{flex-direction:column;justify-content:center;}}@media all and (max-width: 767px){.kadence-column80060_dd95ac-1f > .kt-inside-inner-col{flex-direction:column;justify-content:center;}}<\/style>\n<div class=\"wp-block-kadence-column kadence-column80060_dd95ac-1f inner-column-1 qk-look-widget\"><div class=\"kt-inside-inner-col\">\n<div class=\"wp-block-ultimate-post-row ultp-block-e5a4f2  qk-main-wrap\"><div class=\"ultp-row-wrapper\"><div class=\"ultp-row-content\">\n<div class=\"wp-block-ultimate-post-column ultp-block-0161b4\"><div class=\"ultp-column-wrapper\"><style>.wp-block-kadence-advancedheading.kt-adv-heading80060_45f2c0-1f, .wp-block-kadence-advancedheading.kt-adv-heading80060_45f2c0-1f[data-kb-block=\"kb-adv-heading80060_45f2c0-1f\"]{text-align:center;font-size:20px;font-style:normal;}.wp-block-kadence-advancedheading.kt-adv-heading80060_45f2c0-1f mark.kt-highlight, .wp-block-kadence-advancedheading.kt-adv-heading80060_45f2c0-1f[data-kb-block=\"kb-adv-heading80060_45f2c0-1f\"] mark.kt-highlight{font-family:Inter;font-weight:500;font-style:normal;color:#f76a0c;-webkit-box-decoration-break:clone;box-decoration-break:clone;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;}.wp-block-kadence-advancedheading.kt-adv-heading80060_45f2c0-1f img.kb-inline-image, .wp-block-kadence-advancedheading.kt-adv-heading80060_45f2c0-1f[data-kb-block=\"kb-adv-heading80060_45f2c0-1f\"] img.kb-inline-image{width:150px;vertical-align:baseline;}<\/style>\n<div class=\"kt-adv-heading80060_45f2c0-1f summary-title wp-block-kadence-advancedheading\" data-kb-block=\"kb-adv-heading80060_45f2c0-1f\"><span>Summary<\/span><\/div>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The P2120 code stands for &ldquo;Throttle Position Sensor\/Switch C Circuit Malfunction.&rdquo; It&rsquo;s set by the PCM when it detects a voltage outside the normal operating range.<\/li>\n\n\n\n<li>Some of the common causes of the code include a sticking throttle return spring, MAP or TPS connector issues, and a misrouted harness.<\/li>\n\n\n\n<li>Symptoms to look out for are an illuminated check engine light, misfires, and idling.<\/li>\n<\/ul>\n<\/div><\/div>\n<\/div><\/div><\/div>\n<\/div><\/div>\n\n\n\n\n\n<h2 class=\"wp-block-heading\">What Does a P2120 Code Mean?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/www.carparts.com\/blog\/search-obd2-codes-list\/\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"Diagnostic trouble code\">Diagnostic trouble code<\/a> (DTC) P2120 stands for &ldquo;Throttle Position Sensor\/Switch C Circuit Malfunction.&rdquo; The TPS is a potentiometer located on the throttle body. It detects the angle of the throttle blade. The TPS sends a signal to the PCM (powertrain control module) as the throttle blade moves.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">P2120 is set when the PCM detects a voltage that is outside of its normal operating range. The letter &ldquo;D&rdquo; denotes a specific circuit, sensor, or area of a specific circuit.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">More on Throttle Position Sensors<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">A typical throttle position sensor usually has three wires. These include a 5-volt reference feed wire that sends a message from the computer, a signal return, and a voltage signal wire. As the throttle opens, the voltage sent to the PCM varies.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">If you&rsquo;re planning to diagnose or fix code P2120 yourself, you can read our advanced technical discussion about <a href=\"https:\/\/www.carparts.com\/blog\/p0122-code-throttle-position-sensor-switch-a-circuit-low-input\/#A_Closer_Look_at_Throttle_Position_Sensors\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"throttle position sensors\">throttle position sensors<\/a> for more useful information. A better understanding of the <a href=\"https:\/\/www.carparts.com\/blog\/p2135-code-throttle-pedal-position-sensor-switch-a-b-voltage-correlation\/#How_Code_P2135_is_Set\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"electronic throttle control (ETC) system\">electronic throttle control (ETC) system<\/a> can also help you find the best way to approach the issue.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><em><strong>Note:<\/strong> The definition of the P2120 code can be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.<\/em><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What Are the Common Causes of a P2120 Code?<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Sticking throttle return spring<\/li>\n\n\n\n<li>MAP or TPS connector issues<\/li>\n\n\n\n<li>Misrouted harness<\/li>\n\n\n\n<li>Malfunctioning TPS or <a href=\"https:\/\/www.carparts.com\/blog\/car-pcm-meaning-symptoms-of-failure-and-more\/\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"PCM\">PCM<\/a><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">What Are the Common Symptoms of the P2120 Code?<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.carparts.com\/blog\/check-engine-light-flashing\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"Illuminated check engine light\">Illuminated check engine light<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/www.carparts.com\/blog\/what-is-a-misfire-plus-common-obd-codes-linked-to-a-misfiring-engine\/\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"Engine misfires\">Engine misfires<\/a> when idle or at highway speed<\/li>\n\n\n\n<li>Issues with idling and <a href=\"https:\/\/www.carparts.com\/blog\/car-shuts-off-while-driving-causes-what-to-do\/\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"stalling\">stalling<\/a><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">How to Diagnose the P2120 Code<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Even though DTC P2120 is a generic trouble code, there isn&rsquo;t a universal fix for it. Depending on the make and model of the vehicle, several diagnostic procedures may be required.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"577\" src=\"https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2023\/01\/mechanic-encounters-the-p2120-code-1024x577.jpg\" alt=\"mechanic encounters the p2120 code\" class=\"wp-image-80276\" srcset=\"https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2023\/01\/mechanic-encounters-the-p2120-code-1024x577.jpg 1024w, https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2023\/01\/mechanic-encounters-the-p2120-code-300x169.jpg 300w, https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2023\/01\/mechanic-encounters-the-p2120-code-768x432.jpg 768w, https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2023\/01\/mechanic-encounters-the-p2120-code-1536x865.jpg 1536w, https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2023\/01\/mechanic-encounters-the-p2120-code-150x84.jpg 150w, https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2023\/01\/mechanic-encounters-the-p2120-code.jpg 2000w\" sizes=\"(max-width: 1024px) 100vw, 1024px\"><figcaption class=\"wp-element-caption\">You should leave vehicle repair and diagnosis to a reliable mechanic if you lack experience in these areas.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">In addition to a scan tool, you&rsquo;ll need particular tools and technical details about your throttle position sensor. You should leave vehicle repair and diagnosis to a reliable mechanic if you lack experience in these areas. Otherwise, you can go ahead and identify the problem&rsquo;s root cause on your own.<\/p>\n\n\n\n<div class=\"rsi-card\">\n  <div class=\"rsi-thumb\">\n    <img decoding=\"async\" src=\"https:\/\/cld.partsimg.com\/d_noimage.jpg\/b_white\/e_sharpen,e_auto_brightness,e_auto_contrast\/f_auto\/q_auto:eco,dpr_auto\/w_873,h_873,c_pad\/images\/prmaptps092_1\">\n  <\/div>\n  <div class=\"rsi-info\">\n    <span class=\"rsi-title\">Select the Right Throttle Position Sensor Before You Add It to Cart<\/span>\n    <span class=\"rsi-desc\">Learn how to match the right throttle position sensor, connector, and kit configuration to your vehicle before you add it to cart.<\/span>\n    <a href=\"https:\/\/www.carparts.com\/blog\/select-the-right-throttle-position-sensor-before-you-add-it-to-cart-quickref\/\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"Discover Your Options\">Discover Your Options<\/a>\n  <\/div>\n<\/div>\n\n\n<h2 class=\"wp-block-heading\">How to Fix the P2120 Code<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">It can be challenging to clear the P2120 error code, particularly if you don&rsquo;t have the required DIY and automotive expertise. If that&rsquo;s the case, it&rsquo;s better to bring your car to a shop for repairs so that an expert can handle the situation.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">If, however, you&rsquo;re certain that you can erase the error code by yourself, make sure you have the appropriate repair manual close at hand before beginning. Check out vehicle-specific guides from resources like Chilton or an ALLDATA subscription, if you haven&rsquo;t already.<\/p>\n<\/body><\/html>\n","protected":false},"excerpt":{"rendered":"<p><span class=\"span-reading-time rt-reading-time\" style=\"display: block;\"><span class=\"rt-label rt-prefix\">Reading Time: <\/span> <span class=\"rt-time\"> 2<\/span> <span class=\"rt-label rt-postfix\">minutes<\/span><\/span>What Does a P2120 Code Mean? Diagnostic trouble code (DTC) P2120 stands for &ldquo;Throttle Position Sensor\/Switch C Circuit Malfunction.&rdquo; The&#8230; <a href=\"https:\/\/www.carparts.com\/blog\/p2120-code-throttle-position-sensor-switch-c-circuit-malfunction\/\" rel=\"nofollow\">Read More<\/a><\/p>\n","protected":false},"author":1651,"featured_media":80277,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":true,"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[1314],"tags":[3172,1323,1615,1679],"ppma_author":[2607,2985],"class_list":["post-80060","post","type-post","status-publish","format-standard","has-post-thumbnail","category-obd-ii-trouble-codes","tag-accelerator-pedal","tag-engine-control-module-2","tag-throttle-body","tag-throttle-position-sensor","entry"],"acf":{"adrotate_specific_mobile_ad":"","adrotate_specific_desktop_ad":""},"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.9 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>P2120 Code: Throttle Position Sensor\/Switch C Circuit Malfunction - In The Garage with CarParts.com<\/title>\n<meta name=\"description\" content=\"Find out what a P2120 code stands for and what it could mean for your vehicle. Read on for more information.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.carparts.com\/blog\/p2120-code-throttle-position-sensor-switch-c-circuit-malfunction\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"P2120 Code: Throttle Position Sensor\/Switch C Circuit Malfunction - In The Garage with CarParts.com\" \/>\n<meta property=\"og:description\" content=\"Find out what a P2120 code stands for and what it could mean for your vehicle. Read on for more information.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.carparts.com\/blog\/p2120-code-throttle-position-sensor-switch-c-circuit-malfunction\/\" \/>\n<meta property=\"og:site_name\" content=\"In The Garage with CarParts.com\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/carpartscom\" \/>\n<meta property=\"article:author\" content=\"https:\/\/www.facebook.com\/carpartscom\" \/>\n<meta property=\"article:published_time\" content=\"2023-01-24T07:32:39+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2026-06-19T12:45:30+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2023\/01\/mechanic-troubleshooting-p2120-code-scaled.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"2048\" \/>\n\t<meta property=\"og:image:height\" content=\"1367\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"CarParts.com Research Team, Richard McCuistian, ASE Certified Master Automobile Technician\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@https:\/\/twitter.com\/CarPartscom\" \/>\n<meta name=\"twitter:site\" content=\"@carpartscom\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"CarParts.com Research Team\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"3 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/www.carparts.com\\\/blog\\\/p2120-code-throttle-position-sensor-switch-c-circuit-malfunction\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.carparts.com\\\/blog\\\/p2120-code-throttle-position-sensor-switch-c-circuit-malfunction\\\/\"},\"author\":[{\"@type\":\"Person\",\"$id\":\"1651\",\"name\":\"CarParts.com Research Team\",\"jobTitle\":\"Expert Automotive Writer\",\"description\":\"The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. 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