{"id":46254,"date":"2021-12-02T01:12:49","date_gmt":"2021-12-02T09:12:49","guid":{"rendered":"https:\/\/blogv2prod.wpenginepowered.com\/blog\/?p=46254"},"modified":"2024-06-15T01:07:23","modified_gmt":"2024-06-15T08:07:23","slug":"p20ee-code-scr-nox-catalyst-efficiency-below-threshold-bank-1","status":"publish","type":"post","link":"https:\/\/www.carparts.com\/blog\/p20ee-code-scr-nox-catalyst-efficiency-below-threshold-bank-1\/","title":{"rendered":"P20EE Code: SCR NOx Catalyst Efficiency Below Threshold (Bank 1)"},"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\"> 4<\/span> <span class=\"rt-label rt-postfix\">minutes<\/span><\/span><style>.kadence-column_17bad5-30 > .kt-inside-inner-col{border-top-width:0px;border-right-width:0px;border-bottom-width:0px;border-left-width:0px;}.kadence-column_17bad5-30 > .kt-inside-inner-col,.kadence-column_17bad5-30 > .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-column_17bad5-30 > .kt-inside-inner-col{column-gap:var(--global-kb-gap-sm, 1rem);}.kadence-column_17bad5-30 > .kt-inside-inner-col{flex-direction:column;}.kadence-column_17bad5-30 > .kt-inside-inner-col > .aligncenter{width:100%;}.kadence-column_17bad5-30 > .kt-inside-inner-col:before{opacity:0.3;}.kadence-column_17bad5-30{position:relative;}@media all and (max-width: 1024px){.kadence-column_17bad5-30 > .kt-inside-inner-col{flex-direction:column;justify-content:center;}}@media all and (max-width: 767px){.kadence-column_17bad5-30 > .kt-inside-inner-col{flex-direction:column;justify-content:center;}}<\/style>\n<div class=\"wp-block-kadence-column inner-column-1 kadence-column_17bad5-30 qk-look-widget\"><div class=\"kt-inside-inner-col\">\n<div class=\"wp-block-ultimate-post-row ultp-block-e93147  qk-main-wrap\"><div class=\"ultp-row-wrapper\"><div class=\"ultp-row-content\">\n<div class=\"wp-block-ultimate-post-column ultp-block-9d5ee2\"><div class=\"ultp-column-wrapper\"><style>.wp-block-kadence-advancedheading.kt-adv-heading_a6e7e2-ca, .wp-block-kadence-advancedheading.kt-adv-heading_a6e7e2-ca[data-kb-block=\"kb-adv-heading_a6e7e2-ca\"]{text-align:center;font-size:20px;font-style:normal;}.wp-block-kadence-advancedheading.kt-adv-heading_a6e7e2-ca mark.kt-highlight, .wp-block-kadence-advancedheading.kt-adv-heading_a6e7e2-ca[data-kb-block=\"kb-adv-heading_a6e7e2-ca\"] 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-heading_a6e7e2-ca img.kb-inline-image, .wp-block-kadence-advancedheading.kt-adv-heading_a6e7e2-ca[data-kb-block=\"kb-adv-heading_a6e7e2-ca\"] img.kb-inline-image{width:150px;vertical-align:baseline;}<\/style>\n<div class=\"kt-adv-heading_a6e7e2-ca summary-title wp-block-kadence-advancedheading\" data-kb-block=\"kb-adv-heading_a6e7e2-ca\"><span>Summary<\/span><\/div>\n\n\n\n<ul class=\"wp-block-list\"><li>P20EE stands for &ldquo;SCR NOx Catalyst Efficiency Below Threshold.&rdquo; It usually shows up when the powertrain control module (PCM) detects that catalyst efficiency is below threshold on bank 1.<\/li><li>It&rsquo;s usually caused by a faulty 02, N0x, or exhaust gas temperature sensor, low or contaminated DEF fluid, DEF injector failure, SCR failure, exhaust leaks, circuit problems, or a control module requiring an update.<\/li><li>Some of the symptoms include an illuminated check engine light, exhaust system warning messages on the dash, and derated engine performance.<\/li><\/ul>\n<\/div><\/div>\n<\/div><\/div><\/div>\n<\/div><\/div>\n\n\n\n\n\n<p>On-board diagnostic (OBD) codes help mechanics and vehicle owners identify possible issues in a vehicle. But before you can troubleshoot and resolve these problems, it&rsquo;s important to know what these codes mean.<\/p>\n\n\n\n<p>Code P20EE is one of many trouble codes that may be logged and retrieved from the OBD system. Here is some basic information that may help you understand what getting this code may mean for your vehicle.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What Does the P20EE Code Mean?<\/h2>\n\n\n\n<p><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) P20EE stands for &ldquo;SCR NOx Catalyst Efficiency Below Threshold.&rdquo; This code is logged when the powertrain control module (PCM) detects that catalyst efficiency is below the threshold on bank 1. Code P20EE refers to the selective catalytic reduction catalyst (SCR) on a diesel engine.<\/p>\n\n\n\n<p>Diesel Exhaust Fluid (DEF) helps in converting harmful nitrogen oxides (NOx) into nitrogen (N2) carbon dioxide (CO2) and water. The DEF is injected into the SCR catalyst to perform the chemical reaction.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2021\/11\/Adblue-diesel-exhaust-fluid-DEF-and-diesel-fuel-tank-cap-1024x681.jpg\" alt=\"Adblue diesel exhaust fluid DEF and diesel fuel tank cap\" class=\"wp-image-46308\" width=\"1024\" height=\"681\" srcset=\"https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2021\/11\/Adblue-diesel-exhaust-fluid-DEF-and-diesel-fuel-tank-cap-1024x681.jpg 1024w, https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2021\/11\/Adblue-diesel-exhaust-fluid-DEF-and-diesel-fuel-tank-cap-300x200.jpg 300w, https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2021\/11\/Adblue-diesel-exhaust-fluid-DEF-and-diesel-fuel-tank-cap-768x511.jpg 768w, https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2021\/11\/Adblue-diesel-exhaust-fluid-DEF-and-diesel-fuel-tank-cap-1536x1022.jpg 1536w, https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2021\/11\/Adblue-diesel-exhaust-fluid-DEF-and-diesel-fuel-tank-cap-scaled.jpg 2048w, https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2021\/11\/Adblue-diesel-exhaust-fluid-DEF-and-diesel-fuel-tank-cap-600x400.jpg 600w, https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2021\/11\/Adblue-diesel-exhaust-fluid-DEF-and-diesel-fuel-tank-cap-150x100.jpg 150w\" sizes=\"(max-width: 1024px) 100vw, 1024px\"><figcaption> Diesel Exhaust Fluid (DEF) helps in converting harmful nitrogen oxides (NOx) into nitrogen (N2) carbon dioxide (CO2) and water. <\/figcaption><\/figure>\n\n\n\n<p>The powertrain control module (PCM) monitors the efficiency of the SCR catalyst using NOx sensors. If the SRC fails to efficiently perform its job, code P20EE will be logged.<\/p>\n\n\n\n<p>Depending on the severity of the problem, related error codes may also be stored with this DTC. Code P20EE is very similar to error codes P20EC, P20ED, and P20EF.<\/p>\n\n\n\n<p>Read our discussion about <a href=\"https:\/\/www.carparts.com\/blog\/what-causes-your-def-warning-light-to-switch-on\/#A_Closer_Look_at_DEF\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"DEF\">DEF<\/a> to get more information that can help you address P20EE. Likewise, you can find more useful information in our in-depth discussion about <a href=\"https:\/\/www.carparts.com\/blog\/p0401-code-exhaust-gas-recirculation-egr-flow-insufficient-detected\/#An_In-Depth_Look_at_the_EGR_System\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"EGR systems\">EGR systems<\/a>.<\/p>\n\n\n\n<p><em><strong>Note:<\/strong> The definition of code P20EE may 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 Possible Causes of the P20EE Code?<\/h2>\n\n\n\n<p>P20EE is a generic code, so it can have several triggers. Here are the most common:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Faulty <a href=\"https:\/\/www.carparts.com\/oxygen-sensor\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"O2\">O2<\/a>, <a href=\"https:\/\/www.carparts.com\/nitrogen-oxide-sensor\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"NOx\">NOx<\/a>, or <a href=\"https:\/\/www.carparts.com\/egt-sensor\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"exhaust gas temperature sensor\">exhaust gas temperature sensor<\/a><\/li><li>DEF contamination<\/li><li>DEF injector failure<\/li><li>Insufficient DEF fluid<\/li><li>SCR failure<\/li><li>Leaks in the <a href=\"https:\/\/www.carparts.com\/exhaust-system\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"exhaust system\">exhaust system<\/a><\/li><li>Circuit problems, such as damaged wires and poor connections<\/li><li>A <a href=\"https:\/\/www.carparts.com\/engine-control-module\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"control module\">control module<\/a> issue, such as software in need of an update<\/li><\/ul>\n\n\n\n<div class=\"cp-search\">\n<div align=\"center\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/cld.partsimg.com\/image\/upload\/w_auto,dpr_auto\/carparts\/logos\/badge_wordmark\/full_color\/CP_LOGO_COLOUR_RGB\" alt=\"CarParts.com\" width=\"300\" height=\"56\"><\/div>\n<form id=\"cpsearchform\" name=\"cpsearchform\" action=\"https:\/\/www.carparts.com\/search\" method=\"get\" target=\"_blank\" accept-charset=\"character_set\" aria-label=\"search CarParts.com\">\n\t<input type=\"text\" class=\"keyword\" name=\"q\" placeholder=\"Search for parts on CarParts.com\" value=\"\" aria-label=\"Search CarParts.com\">\n        <input type=\"submit\" class=\"btn-search\" value=\"Search\" aria-label=\"Search\">\n<\/form><\/div>\n\n\n\n<h2 class=\"wp-block-heading\">What are the Common Symptoms of the P20EE Code?<\/h2>\n\n\n\n<p>You may notice the following symptoms if you drive a vehicle that has set a P20EE trouble code:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/www.carparts.com\/blog\/check-engine-light-flashing\/\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"Active check engine light\">Active check engine light<\/a><\/li><li>Exhaust system warning messages on the dash<\/li><li>Derated engine performance<\/li><li>Poor fuel efficiency<\/li><li>DPF regeneration may not happen<\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">How to Diagnose the P20EE Code<\/h2>\n\n\n\n<p>Error code P20EE is a generic code that may be set in different makes and models. However, this does not mean that there is a one-size-fits-all approach to diagnosing its underlying cause. The steps for troubleshooting this code will vary depending on your specific vehicle.<\/p>\n\n\n\n<p>Check out the video below to get an idea of what the diagnostic process for this code might involve:<\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"P20EE Fault Code\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/3VCUtlX1ROE?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">How to Fix the P20EE Code<\/h2>\n\n\n\n<p>Although code P20EE shares similar triggers and symptoms with other engine codes, the appropriate diagnostic and repair procedure will depend on the specifications of your vehicle. If you&rsquo;re unfamiliar with auto repair, you should leave the job to a mechanic.<\/p>\n\n\n\n<p>If you&rsquo;re considering troubleshooting this code on your own, it&rsquo;s a good idea to refresh your automotive knowledge before attempting any fixes. Always consult the <a href=\"https:\/\/www.carparts.com\/blog\/why-you-should-always-consult-a-repair-manual\/\" target=\"_blank\" rel=\"noreferrer noopener\" aria-label=\"vehicle repair manual or an online repair database\">vehicle repair manual or an online repair database<\/a> to learn the appropriate diagnostic procedures for this code.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Where To Buy Parts for the P20EE Code<\/h2>\n\n\n\n<p>Given the many potential causes of the P20EE code, you might find you need a lot of different parts to get it fixed. Whether it&rsquo;s a faulty temperature sensor or damaged wires, you can find the items you need here at CarParts.com!<\/p>\n\n\n\n<p>Our website is easy to navigate and well-stocked with a wide selection of aftermarket brands. You won&rsquo;t have to look for too long before finding the parts that fit your budget and needs. Use our built-in vehicle selector to find the parts specially made for your vehicle, check out, and you&rsquo;ll be good to go!<\/p>\n\n\n\n<p>As a leading online retailer, we want you to feel secure buying online. That&rsquo;s why we offer returns within 60 days of purchase with a money-back guarantee if you aren&rsquo;t satisfied. Browse our catalog today and get the perfect parts to restore your vehicle.<\/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\"> 4<\/span> <span class=\"rt-label rt-postfix\">minutes<\/span><\/span>On-board diagnostic (OBD) codes help mechanics and vehicle owners identify possible issues in a vehicle. But before you can troubleshoot&#8230; <a href=\"https:\/\/www.carparts.com\/blog\/p20ee-code-scr-nox-catalyst-efficiency-below-threshold-bank-1\/\" rel=\"nofollow\">Read More<\/a><\/p>\n","protected":false},"author":4,"featured_media":46307,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_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":[3158,3157,1190],"ppma_author":[2607,2985],"class_list":{"0":"post-46254","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-obd-ii-trouble-codes","8":"tag-egt-sensor","9":"tag-nitrogen-oxide-sensor","10":"tag-oxygen-sensor-2","11":"entry"},"acf":{"adrotate_specific_mobile_ad":"","adrotate_specific_desktop_ad":""},"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.8 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>P20EE Code: SCR NOx Catalyst Efficiency Below Threshold (Bank 1) - In The Garage with CarParts.com<\/title>\n<meta name=\"description\" content=\"Find out what code P20EE means, its triggers, usual symptoms, and the common solutions you can try to resolve this trouble code.\" \/>\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\/p20ee-code-scr-nox-catalyst-efficiency-below-threshold-bank-1\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"P20EE Code: SCR NOx Catalyst Efficiency Below Threshold (Bank 1) - In The Garage with CarParts.com\" \/>\n<meta property=\"og:description\" content=\"Find out what code P20EE means, its triggers, usual symptoms, and the common solutions you can try to resolve this trouble code.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.carparts.com\/blog\/p20ee-code-scr-nox-catalyst-efficiency-below-threshold-bank-1\/\" \/>\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:published_time\" content=\"2021-12-02T09:12:49+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2024-06-15T08:07:23+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.carparts.com\/blog\/wp-content\/uploads\/2021\/11\/male-mechanic-does-a-quick-diagnostic-check-with-special-tools-in-hand.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"1700\" \/>\n\t<meta property=\"og:image:height\" content=\"1133\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@carpartscom\" \/>\n<meta name=\"twitter:site\" content=\"@carpartscom\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"4 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/www.carparts.com\\\/blog\\\/p20ee-code-scr-nox-catalyst-efficiency-below-threshold-bank-1\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.carparts.com\\\/blog\\\/p20ee-code-scr-nox-catalyst-efficiency-below-threshold-bank-1\\\/\"},\"author\":[{\"@type\":\"Person\",\"$id\":\"4\",\"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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Richard has worked for nearly 50 years in the automotive field as a professional technician, an instructor, a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others (published every year since May 2000). He has developed training courses and written or edited training material for companies in the U.S. Canada, and the Netherlands, and even Bulgaria. He maintained an \u201cask a mechanic\u201d website for 10 years answering questions emailed to him from all over the world.\r\n\r\nRichard has an instructional automotive YouTube channel \u201cMcCuistian\u201d with 13,500 subscribers and over 1,300 videos. Much of his professional work requires photography and videography in shop environments, but Richard also enjoys taking pictures of landscapes, skyscapes, old barns and houses, small towns. He has produced a coffee table book of digital watercolors called \u201cMemories of South Alabama\u201d created from his personal photos, along with a dozen Christian fiction short original novels and a collection of short stories, all available in Kindle or softcover format. 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He has won two International Automotive Media Awards for technical articles published in trade magazines.<\/p><\/li>\r\n<li><p>Has attended hundreds of hours of automotive training from OEMs including GM, Volkswagen, Mazda, Renault, Jeep, Chrysler, as well as additional training at events like KC Vision and MACS (Mobile Air Climate Systems Association).<\/p><\/li>\r\n<li><p>Taught college level auto mechanics for 19 years.<\/p><\/li>\r\n<li><p>Has written for automotive training companies (including course development work for training companies in Canada and the Netherlands) and has been hired to teach professional trade show technician courses at multiple training events in Texas and Alabama.<\/p><\/li>\r\n<li><p>While still teaching at the college level, Richard launched a new automotive program in Geneva, Alabama, setting up a dual enrollment department in a new building, organizing the shop and classroom, teaching morning classes to high school students for 2 years while still teaching at the college in the afternoon.<\/p><\/li>\r\n<li><p>Richard\u2019s college program at Lurleen B. 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