{"id":5112,"date":"2019-09-20T08:00:42","date_gmt":"2019-09-20T07:00:42","guid":{"rendered":"https:\/\/www.purplemeanie.co.uk\/?p=5112"},"modified":"2026-05-28T11:49:56","modified_gmt":"2026-05-28T10:49:56","slug":"ecu-diagnostics-part-13-three-diagnostic-protocols-in-the-mbe-9a4-ecu","status":"publish","type":"post","link":"https:\/\/purplemeanie.co.uk\/index.php\/2019\/09\/20\/ecu-diagnostics-part-13-three-diagnostic-protocols-in-the-mbe-9a4-ecu\/","title":{"rendered":"ECU Diagnostics &#8211; part 13 : Three Diagnostic Protocols in the MBE 9A4 ECU"},"content":{"rendered":"\n<p>This one&#8217;s just a short post to introduce the next three posts. In our investigations of the MBE 9A4 ECU we&#8217;ve found three different diagnostics protocols supported on the OBD port.<\/p>\n\n\n\n<p>The following three posts will summarise what we&#8217;ve learnt about each protocol and will be updated with new information as it becomes available.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>13.1 MBE-Broadcast<\/li><li>13.2 OBD-II<\/li><li>13.3 MBE-ISOTP<\/li><\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Introduces the three diagnostic protocols found on the Caterham MBE 9A4 ECU: MBE-Broadcast, OBD-II, and the MBE ISO-TP protocol used by Easimap.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[51,20],"tags":[58,66,34,60,59],"class_list":["post-5112","post","type-post","status-publish","format-standard","hentry","category-caterham-blog","category-ecu-diagnostics","tag-can-bus","tag-caterham","tag-ecu-diagnostics","tag-mbe","tag-obd"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p8yl38-1ks","jetpack-related-posts":[{"id":4726,"url":"https:\/\/purplemeanie.co.uk\/index.php\/2019\/08\/31\/ecu-diagnostics-part-1-introduction\/","url_meta":{"origin":5112,"position":0},"title":"ECU Diagnostics &#8211; part 1 : Introduction","author":"John Martin","date":"August 31, 2019","format":false,"excerpt":"Introduction and index for the Caterham ECU diagnostics series, covering MBE ECU traffic, CAN bus, OBD-II, ISO-TP, test setup, protocol decoding, and supporting Python and Wireshark tooling.","rel":"","context":"In &quot;Caterham Blog&quot;","block_context":{"text":"Caterham Blog","link":"https:\/\/purplemeanie.co.uk\/index.php\/category\/caterham-blog\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":5192,"url":"https:\/\/purplemeanie.co.uk\/index.php\/2019\/09\/20\/ecu-diagnostics-part-14-software-framework-mbe-py\/","url_meta":{"origin":5112,"position":1},"title":"ECU Diagnostics &#8211; part 14 : Software Framework mbe.py","author":"John Martin","date":"September 20, 2019","format":false,"excerpt":"Introduces the Python mbe.py framework for sending requests to the Caterham MBE 9A4 ECU and formatting diagnostic responses into readable values.","rel":"","context":"In &quot;Caterham Blog&quot;","block_context":{"text":"Caterham Blog","link":"https:\/\/purplemeanie.co.uk\/index.php\/category\/caterham-blog\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":4765,"url":"https:\/\/purplemeanie.co.uk\/index.php\/2019\/08\/31\/ecu-diagnostics-part-2-ecu-obd-and-can\/","url_meta":{"origin":5112,"position":2},"title":"ECU Diagnostics \u2013 part 2 : ECU, OBD and CAN","author":"John Martin","date":"August 31, 2019","format":false,"excerpt":"Explains the Caterham MBE 9A4 ECU, how it exposes diagnostic data, and how OBD and CAN bus concepts fit into the ECU diagnostics project.","rel":"","context":"In &quot;Caterham Blog&quot;","block_context":{"text":"Caterham Blog","link":"https:\/\/purplemeanie.co.uk\/index.php\/category\/caterham-blog\/"},"img":{"alt_text":"MBE 9A4 ECU module label on a purple background.","src":"https:\/\/i0.wp.com\/purplemeanie.co.uk\/wp-content\/uploads\/2019\/08\/9A4.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":5134,"url":"https:\/\/purplemeanie.co.uk\/index.php\/2019\/09\/20\/ecu-diagnostics-part-13-2-obd-ii\/","url_meta":{"origin":5112,"position":3},"title":"ECU Diagnostics &#8211; part 13.2 : OBD-II","author":"John Martin","date":"September 20, 2019","format":false,"excerpt":"Summarises what standard OBD-II services and PID data the Caterham MBE 9A4 ECU supports and how that data appears on the CAN bus.","rel":"","context":"In &quot;Caterham Blog&quot;","block_context":{"text":"Caterham Blog","link":"https:\/\/purplemeanie.co.uk\/index.php\/category\/caterham-blog\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":4769,"url":"https:\/\/purplemeanie.co.uk\/index.php\/2019\/09\/01\/ecu-diagnostics-part-3-test-setup\/","url_meta":{"origin":5112,"position":4},"title":"ECU Diagnostics &#8211; part 3 : Test Setup","author":"John Martin","date":"September 1, 2019","format":false,"excerpt":"Sets up the Caterham ECU diagnostics test rig using the OBD port, Raspberry Pi, PiCAN interface, Easimap, and CAN bus capture hardware.","rel":"","context":"In &quot;Caterham Blog&quot;","block_context":{"text":"Caterham Blog","link":"https:\/\/purplemeanie.co.uk\/index.php\/category\/caterham-blog\/"},"img":{"alt_text":"Diagram linking Raspberry Pi, PiCAN, MBE 9A4 ECU, and a laptop running Easimap.","src":"https:\/\/i0.wp.com\/purplemeanie.co.uk\/wp-content\/uploads\/2019\/08\/Test-Setup-Diagram.png?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/purplemeanie.co.uk\/wp-content\/uploads\/2019\/08\/Test-Setup-Diagram.png?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/purplemeanie.co.uk\/wp-content\/uploads\/2019\/08\/Test-Setup-Diagram.png?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/purplemeanie.co.uk\/wp-content\/uploads\/2019\/08\/Test-Setup-Diagram.png?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/purplemeanie.co.uk\/wp-content\/uploads\/2019\/08\/Test-Setup-Diagram.png?resize=1050%2C600&ssl=1 3x"},"classes":[]},{"id":5086,"url":"https:\/\/purplemeanie.co.uk\/index.php\/2019\/09\/16\/ecu-diagnostics-part-12-osi-7-layers-for-caterham-diagnostics\/","url_meta":{"origin":5112,"position":5},"title":"ECU Diagnostics &#8211; part 12 : OSI 7 Layers for Caterham Diagnostics","author":"John Martin","date":"September 16, 2019","format":false,"excerpt":"Maps the Caterham diagnostics stack onto the OSI model, from CAN bus hardware through MBE ISO-TP layers up to Python tooling and applications.","rel":"","context":"In &quot;ECU Diagnostics&quot;","block_context":{"text":"ECU Diagnostics","link":"https:\/\/purplemeanie.co.uk\/index.php\/category\/caterham-blog\/ecu-diagnostics\/"},"img":{"alt_text":"Layered diagram mapping the MBE ECU protocol stack to OSI layers and CAN bus.","src":"https:\/\/i0.wp.com\/purplemeanie.co.uk\/wp-content\/uploads\/2019\/09\/ECU-OSI-Layers.png?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/purplemeanie.co.uk\/wp-content\/uploads\/2019\/09\/ECU-OSI-Layers.png?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/purplemeanie.co.uk\/wp-content\/uploads\/2019\/09\/ECU-OSI-Layers.png?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/purplemeanie.co.uk\/wp-content\/uploads\/2019\/09\/ECU-OSI-Layers.png?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/purplemeanie.co.uk\/wp-content\/uploads\/2019\/09\/ECU-OSI-Layers.png?resize=1050%2C600&ssl=1 3x"},"classes":[]}],"jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/purplemeanie.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/5112","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/purplemeanie.co.uk\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/purplemeanie.co.uk\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/purplemeanie.co.uk\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/purplemeanie.co.uk\/index.php\/wp-json\/wp\/v2\/comments?post=5112"}],"version-history":[{"count":2,"href":"https:\/\/purplemeanie.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/5112\/revisions"}],"predecessor-version":[{"id":11513,"href":"https:\/\/purplemeanie.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/5112\/revisions\/11513"}],"wp:attachment":[{"href":"https:\/\/purplemeanie.co.uk\/index.php\/wp-json\/wp\/v2\/media?parent=5112"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/purplemeanie.co.uk\/index.php\/wp-json\/wp\/v2\/categories?post=5112"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/purplemeanie.co.uk\/index.php\/wp-json\/wp\/v2\/tags?post=5112"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}