From 922eb66aa4f083f393cbb60e7f88674b379c7995 Mon Sep 17 00:00:00 2001 From: rusefillc <48498823+rusefillc@users.noreply.github.com> Date: Sat, 11 Mar 2023 23:47:46 -0500 Subject: [PATCH] Update E24-SEFMJ-white-civic-si.md --- .../E24-SEFMJ-white-civic-si.md | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/OEM-Docs/Honda/E24-SEFMJ-white-civic-si/E24-SEFMJ-white-civic-si.md b/OEM-Docs/Honda/E24-SEFMJ-white-civic-si/E24-SEFMJ-white-civic-si.md index 020a3a03..023c6450 100644 --- a/OEM-Docs/Honda/E24-SEFMJ-white-civic-si/E24-SEFMJ-white-civic-si.md +++ b/OEM-Docs/Honda/E24-SEFMJ-white-civic-si/E24-SEFMJ-white-civic-si.md @@ -1,9 +1,9 @@ # General Context -SEFMJ Honda protocol running 9600 K-line communication between 2004 Honda ECU and multiplex module within body control unit / cabin fuse box. +SEFMJ Honda protocol running 9600 K-line (effectively 12v serial port) communication between 2004 Honda ECU and multiplex module within body control unit (BCM) / cabin fuse box. -Some packets are sent my BCM some packets are sent by ECU. Assumption is that BCM is master thus first packet in the cycle is coming from BCM. +Some packets are sent my BCM, some packets are sent by ECU. Assumption is that BCM is master thus first packet in the cycle is coming from BCM. ![image](https://user-images.githubusercontent.com/48498823/224524802-0bbde452-66a4-43b7-95c5-b523dc23cb63.png) @@ -13,14 +13,25 @@ Byte packets are clearly CRC-terminated, for instance 0x140 is crc of 1,0,0 pack ![image](https://user-images.githubusercontent.com/48498823/224524734-9c9ed54d-0ecd-4aa1-a46e-3e1f9ce53acb.png) +# Available data + +Schematics: A bunch of 2003-acura-rsx PDF files at https://github.com/rusefi/rusefi_documentation/tree/master/OEM-Docs/Honda + +* Bench setup in NJ: just BCM sending out same five byte packet see https://rusefi.com/forum/viewtopic.php?p=47371#p47371 +* a bunch of logic analyzer recordings of real while honda civic, see below + # Problem statement -* ECU seem to be reporting CLT temperature to BDM and eventually for dash board / instrument cluster +* ECU seem to be reporting CLT temperature to BDM and eventually for dash board / instrument cluster. -* BDM seem to be reporting state of A/C request button to ECU +* BCM seem to be reporting state of A/C request button to ECU. +Open question: which packets are sent by which of the two devices? +Open question: how is A/C request encoded? Partial answer: looks like third byte 0x80 see https://github.com/rusefi/hellen125honda-issues/issues/26#issuecomment-1464826791 + +Open question: how is CLT encided in what packets? # What we have