K-Line

K-Line on SIMK43 runs at 10400 baud and uses the KWP2000 protocol for diagnostic communication.

Connection points

ECU

If you have 1.6 or 2.0 without immobilizer installed:

Good news! Your K-Line pins (OBD2/MCC) are connected directly to the K-line pin on the ECU (2.0 - 77)

If you have 1.6 or 2.0 with immobilizer installed:

Your K-Line pins (OBD2/MCC) are connected to BCM's "Diagnosis" pin (BCM-IM, pin 19). THERE IS NOTHING CONNECTED TO K-LINE PIN AT THE ECU!! (2.0 77). Instead, all K-line stuff is connected to the ECU's W-Line (2.0 - 47)

If you have 2.7 with or without immobilizer installed:

Your K-Line pins (OBD2/MCC) are connected to BCM's "Diagnosis" pin (BCM-IM, pin 19). Your K/Immo-Line pin at the ECU (C133-1, pin 3) is connected to BCM's "Immo W-line" (BCM-IM, pin 20). 2.7 ECUs don't have a separate K and W line - it's all integrated in one pin, you don't have nothing to worry about.

KWP2000

To start communication, you need to use Fast Init - so bring the K-line down for exactly 25ms, then up for 25ms followed by StartCommunication request. Python example of that using a FTDI cable can be found in GKBus code.

ID of the ECU is 0x11, and as a diagnostic device you should be using ID 0xF1. So an example command and response would look like this:

Diagnostic device: 82 11 F1 27 01 AC (security access request)

ECU response: 83 F1 11 67 02 34 22

Baudrate

By default, SIMK43 uses 10400 baud. On some ECUs (so far testing revealed that <2005 ECUs might not support that), baudrate can be manipulated by additional undocumented parameter of the StartDiagnosticSession service:

0x01: 10400

0x02: 20000

0x03: 40000

0x04: 60000

0x05: 120000

Challenge-response calculation

SIMK43/41 uses a 2 byte seed and 2 byte key for security access. Until a write-up about the algorithm is prepared, you can take a look at it's Python implementation in GKFlasher: https://github.com/Dante383/GKFlasher/blob/15a715b18f2119d697a5ceed00f6383f690c4a23/ecu.py#L42

Input-Output local identifiers

Identifier (hex)	Description	Notes
0x10	check engine light
0x11	EVAP canister close valve (on)
0x12	fuel pump relay
0x14	fuel pump control
0x16	"Canister Close Valve-Clocked" (whatever that means)
0x1A	cooling fan relay high
0x1B	cooling fan relay low
0x1C	main relay
0x20	canister purge valve
0x23	idle speed actuator
0x24	cvvt valve
0x31	ignition coil #1, 4
0x32	ignition coil #2, 5	Coil #5 v6 only
0x33	ignition coil #3, 6	Coil #6 v6 only
0x39	injector cylinder 1	i4 only
0x3A	injector cylinder 2	i4 only
0x3B	injector cylinder 3	i4 only
0x3C	injector cylinder 4	i4 only
0x300701	injector cylinder 1	v6 only
0x300702	injector cylinder 2	v6 only
0x300704	injector cylinder 3	v6 only
0x300708	injector cylinder 4	v6 only
0x300710	injector cylinder 5	v6 only
0x300720	injector cylinder 6	v6 only
0x41	Version Configuration	Automatic Transaxle (0x08) - This is the ECU reset function to install M/T or Non-TCS system.
0x42	Version Configuration	Traction Control System (0x08) - This is the ECU reset function to install M/T or Non-TCS system.
0x50	adaptive values	0x04 - clear function

Routines by local identifier

0x00 - erase program section

0x01 - erase calibration section

0x02 - verify and mark blocks as ready to execute. Needs to be called after flashing

0x03 - unknown. requires security access, returned 0x33 0xE0 on a bench ecu

0x04 - unknown, returns 0x22 - Conditions Not Correct Or Request Sequence Error

0x05 - unknown, returns 0x22 - Conditions Not Correct Or Request Sequence Error

0x12 - query immobilizer info: 2 bytes number of keys learnt, 2 bytes immo status (01 = learnt), 2 bytes key status (00 - not learnt), 2 bytes smartra status if applicable

0x13 - needs to be called before immobilizer password teaching/changing

0x14 - needs to be called before immobilizer teaching.

0x15 - needs to be called before ECU immobilizer reset

0x16 - needs to be called before putting immobilizer in limp home mode

0x17 - input new limp home password

0x18 - activate limp home mode. takes user-provided (default: 2345) password as parameters

0x19 - confirm limp home password change. takes 0x01 as a parameter

0x1A - input 6 digit immobilizer password. Needs to be called before teaching, resetting or other actions modifying the immo system. Takes password and 6x 0xFF as parameters

0x1B, 0x1C, 0x1D, 0x1E - teach keys 1,2,3,4. Takes 0x01 as a parameter

0x20 - reset ECU immo. Takes 0x01 as a parameter

0x25 - needs to be called before neutralizing smartra

0x26 - confirm neutralizing smartra. takes 0x01 as a parameter