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IMPORTANT: enter the case-INsensitive alphabetic (no numbers) code AND WRITE SOME SHORT summary of changes (below) if you are saving changes. (not required for previewing changes). Wiki-spamming is not tolerated, will be removed, so it does NOT even show up in history. Spammers go away now. Visit Preferences to set your user name Summary of change: Subpage of MembersPage/BmwMFiftyTwo When installing ECU with Motronic88 connector to the BMW M52 harness, verify the following: '''ECU Unplugged''' * '''mot88/73''' is connected to main relay control pin (DVM connectivity test) * main '''relay resistance''' = ... Ohm (fill this in, should be between 75..150 Ohm) '''Ignition off:''' * main relay is NOT powered '''Ignition on:''' * DVM DC voltage mode (+12V as a base): ** '''main relay control pin''' (same as mot88/73 verified before) '''measures appr -12V''' (if DVM black is connected to +12V). * This mean that main relay is powered by the ECU (actually EC36/16 (p259/ch1) output, configured via MISC1 output function "always ON") ---- '''Main relay not switching ON when ECU powered, possible causes''' * '''main relay coil not getting +12V''' (can be '''rectified locally''') * or '''ECU does not pull down the mot88/73''' ** ('''most likely configuration, can be rectified locally''') ** or something else * '''Main relay contact problem (can be rectified locally)''' * Main '''relay faulty (can be rectified locally)''' ---- '''Check config''' Download [http://vems.hu/download/v3/Motronic88/M52/ .vemscfg] and compare. * capture a short vemslog, and publish on your MembersPage ---- '''Ignition ON:''' (test example) http://vems.hu/download/v3/Motronic88/M52/BMW_M52_testing/BMW_M52_harness_mainrelay_testing1_l.jpg * '''VT is CONNECTED''' * '''main relay is powered''' (0.08A) ** '''mot88/73''' is pulled to GND via (EC36/16 = p259/ch1) ** actually configured via MISC1 output function. ---- If '''ignition is OFF''' (ECU does not get +12V power via M52/49=EC36/25 supply), then * '''VT is disconnected''' * '''main relay is off''' (0.00A) ** even though ECU is plugged in and harness is powered ** so it's not just some wire inside the ECU, main relay control pin '''mot88/73''' is only pulled to GND when ECU is powered by ignition ON. http://vems.hu/download/v3/Motronic88/M52/BMW_M52_testing/BMW_M52_harness_mainrelay_testing0_m.jpg Optional: Add document to category: Wiki formatting: * is Bullet list ** Bullet list subentry ... '''Bold''', ---- is horizontal ruler, <code> preformatted text... </code> See wiki editing HELP for tables and other formatting tips and tricks.