{"id":22106,"date":"2024-09-18T08:40:45","date_gmt":"2024-09-18T08:40:45","guid":{"rendered":"https:\/\/www.obd2tool.com\/blog\/?p=22106"},"modified":"2024-09-21T08:45:32","modified_gmt":"2024-09-21T08:45:32","slug":"jcb-tier-4-engine-start-relay-high-voltage-and-current-above-normal","status":"publish","type":"post","link":"https:\/\/www.obd2tool.com\/blog\/jcb-tier-4-engine-start-relay-high-voltage-and-current-above-normal\/","title":{"rendered":"JCB Tier 4 Engine &#8211; Start Relay High Voltage and Current Above Normal"},"content":{"rendered":"<p>This guide provides steps to resolve high voltage and current issues related to the start relay on JCB Tier 4 engines, specifically for fault codes SPN 1321, FMI 3 and FMI 6 at start-up.<\/p>\n<h4>Related Contents:<\/h4>\n<ul>\n<li class=\"thumb\"><a href=\"https:\/\/www.obd2tool.com\/goods-4451-JCB-Electronic-Service-Tool-JCB-Diagnostic-Interface.html\"><img src=\"https:\/\/www.obd2tool.com\/images\/202409\/goods_img\/4451_G_1725357343332.jpg\" alt=\"JCB Heavy Duty Truck Diagnostic Tool JCB Electronic Service Tool with JCB ServiceMaster 4 V1.73.3 or V24.09\" \/><\/a><\/li>\n<li class=\"goodsName\">\n<div class=\"goods-name-text\"><a href=\"https:\/\/www.obd2tool.com\/goods-4451-JCB-Electronic-Service-Tool-JCB-Diagnostic-Interface.html\"> JCB Heavy Duty Truck Diagnostic Tool JCB Electronic Service Tool with JCB ServiceMaster 4 V1.73.3 or V24.09 <\/a><\/div>\n<\/li>\n<\/ul>\n<ul>\n<li class=\"thumb\"><a href=\"https:\/\/www.obd2tool.com\/goods-10573-JCB-Service-Master-4-Diagnostic-Software.html\"><img src=\"https:\/\/www.obd2tool.com\/images\/202409\/goods_img\/10573_G_1726213788280.jpg\" alt=\"JCB Service Master 4 V24.09 Diagnostic Software 2024.09\" \/><\/a><\/li>\n<li class=\"goodsName\">\n<div class=\"goods-name-text\"><a href=\"https:\/\/www.obd2tool.com\/goods-10573-JCB-Service-Master-4-Diagnostic-Software.html\"> JCB Service Master 4 V24.09 Diagnostic Software 2024.09 <\/a><\/div>\n<\/li>\n<\/ul>\n<h3>Start Relay High Voltage Above Normal<\/h3>\n<p><strong>Description:<\/strong><\/p>\n<p>The start relay voltage is detected above the normal operating range.<\/p>\n<p><strong>Possible Causes:<\/strong><\/p>\n<ul>\n<li>Faulty wiring of the start relay.<\/li>\n<li>Defective start relay.<\/li>\n<\/ul>\n<p><strong>Engine Control Module (ECM) Response:<\/strong><\/p>\n<ul>\n<li>The fault code (FC) is stored.<\/li>\n<li>The warning light is activated.<\/li>\n<li>The CAN bus sends a message indicating an active error.<\/li>\n<\/ul>\n<p><strong>Solution:<\/strong><\/p>\n<ol>\n<li>Save and clear the error log.<\/li>\n<li>Restart the ECU.<\/li>\n<li>If the fault reoccurs in the next drive cycle, follow these steps:\n<ul>\n<li>Inspect the wiring, connectors, and pin contacts for the start relay (look for oxidation or damage).<\/li>\n<li>Test with a known-good relay to verify if the original relay is faulty.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<h3>Start Relay High Side Current Above Normal<\/h3>\n<p><strong>Description:<\/strong><\/p>\n<p>The start relay&#8217;s current is detected above the normal operating range.<\/p>\n<p><strong>Possible Causes:<\/strong><\/p>\n<ul>\n<li>Defective wiring of the start relay.<\/li>\n<li>Faulty start relay.<\/li>\n<\/ul>\n<p><strong>ECM Response:<\/strong><\/p>\n<ul>\n<li>The fault code is saved.<\/li>\n<li>The warning light is illuminated.<\/li>\n<li>The CAN message indicates an active fault.<\/li>\n<\/ul>\n<p><strong>Solution:<\/strong><\/p>\n<ol>\n<li>Save and clear the error log.<\/li>\n<li>Restart the ECU.<\/li>\n<li>If the fault reappears during the next driving cycle:\n<ul>\n<li>Inspect the start relay wiring, plugs, and pin contact surfaces (oxidation could be an issue).<\/li>\n<li>Test the start relay by replacing it with a known-good relay.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<p>By following these steps, you can diagnose and resolve start relay voltage and current issues on JCB Tier 4 engines.<\/p>\n<!-- AddThis Advanced Settings generic via filter on the_content --><!-- AddThis Share Buttons generic via filter on the_content -->","protected":false},"excerpt":{"rendered":"<p>This guide provides steps to resolve high voltage and current issues related to the start relay on JCB Tier 4<!-- AddThis Advanced Settings generic via filter on get_the_excerpt --><!-- AddThis Share Buttons generic via filter on get_the_excerpt --><\/p>\n","protected":false},"author":1,"featured_media":22107,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[65,2959],"tags":[3686,2651,2652,3687],"views":1322,"_links":{"self":[{"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/posts\/22106"}],"collection":[{"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/comments?post=22106"}],"version-history":[{"count":1,"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/posts\/22106\/revisions"}],"predecessor-version":[{"id":22108,"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/posts\/22106\/revisions\/22108"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/media\/22107"}],"wp:attachment":[{"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/media?parent=22106"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/categories?post=22106"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.obd2tool.com\/blog\/wp-json\/wp\/v2\/tags?post=22106"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}