XC40 CEM pinout & canbus | SwedeSpeed

Hi Guys,

I am new to this forum and sorry if this question repeats, but I could not find the answer. OK let start from beginning. I have Volvo XC40 2021/2022 – CEM – 32268108 AB -> SPC 5748G (Power Arch) on my garage bench, but I believe this same CEM goes to XC60 and others. I am trying to connect to this CEM via CAN bus and play around just for my curiosity. Straight away I have faced the issue.

OK let explain, what I did and trying to do. I found on internet this electrical wiring manual MC-10236765-9999.pdf and figured out that I need use those pins to connect to power it the CEM:

Code:

12V possitive

--30--> Constant power from the battery

Power_supply_KL30A - PO1 -> SA1011C 2TBD 6.0 RD
Power_supply_KL30B - PO2 -> SA1012C 2TBD 6.0 RD/YE

--15--> Contact remains connected during start

IgnitionPowerRelayFB - EN9 -> SG1017B 2TBD 0.35 BU/GN

12V negative

El1_GND - FL64
EL2_GND - FL65

--CanBus-- 500kpbs

CANHS+ - FL20 -> CG1401AA 2TBD 0.35 VT/WH
CANHS- - FL19 -> CH1402AA 2TBD 0.35 VT/GN

Attaching screenshot of my findings (page 9, 10, 15 & 19) and EWD .pdf file attached below.

Once I power the CEM I see traffic on the CAN bus, but I can not get response back from a CEM, when I do send messages like:

Code:

7DF 023E800000000000 -> Tester present with functional id
7DF 0210820000000000 -> Extended session with functional id
726 0322F19000000000 -> Show VIN
726 0210020000000000 -> Start Session

What I see on Can Bus, like this going in the loop:

Code:

0E3   [8]  E0 00 00 00 00 00 00 00
5AC   [8]  0D 00 00 00 00 00 00 00
57F   [4]  10 09 C0 00
020   [8]  CF BC C9 C0 10 12 20 0F
032   [8]  00 00 00 00 00 00 1B 20
033   [8]  00 00 00 00 00 00 07 D0
035   [8]  00 00 00 00 00 00 10 00
038   [8]  00 00 00 00 00 00 05 00
03A   [8]  00 00 00 00 00 00 00 00
053   [8]  00 00 00 00 00 00 00 00
0B0   [8]  00 00 00 00 55 00 20 02
100   [8]  00 85 00 5B 69 00 0D 06
120   [8]  3C 00 00 00 00 00 1C 00
189   [8]  00 00 00 00 00 00 00 00
200   [8]  00 00 00 00 01 80 00 00
210   [8]  5A 03 32 00 00 00 00 00
215   [8]  00 00 00 00 00 00 00 01
220   [8]  00 00 00 00 00 00 00 00
340   [8]  39 00 00 00 00 00 00 00
360   [8]  02 56 31 4D 32 34 34 39
380   [8]  01 F4 01 2C A8 00 00 1C
040   [8]  00 00 20 40 40 15 60 00
05A   [8]  FF 05 00 00 80 00 09 04
020   [8]  CF 3C C9 C0 10 12 20 0E
032   [8]  00 00 00 00 00 00 1B 20
033   [8]  00 00 00 00 00 00 07 D0
035   [8]  00 00 00 00 00 00 10 00
038   [8]  00 00 00 00 00 00 05 00
03A   [8]  00 00 00 00 00 00 00 00
5AC   [8]  0C 00 00 00 00 00 00 00

and because I am not sure if on new CMA/SPA cars on CAN Bus system CEM still address called canIdTX – 72E, canIdRX – 726, that is why I did used all addresses from 0x70[0-7] to 0x7F[0-7] to test, but still with no luck get response.

I know that if you want go diagnostics on the XC40 you need press Start/Stop button for 5 sec.
Here it comes my question. When you press button for 5 sec is CEM goes to some kind diagnostic mode, like some pin gets additional 12V+ of power? Or might on CAN bus some module like VCM sends specific message like: (7DF 023E800000000000 -> Tester present etc?)? Or I might missing some additional power connection to CEM to get CEM work properly?

I understand I ask difficult questions, but I believe there are lot of clever people on this forum than me and they can direct me to correct way. Thank you in advance for any answer.

Regards,

binary miller

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