Continuous AP VEH bus

[HamzaObaidat]

Can we use the car's bus for the Continuous AP feature?

I know it works in rear and front installations in Enhauto Commander.

I tried sniffing 0x399, but the signals haven't changed at all

[hypery11]

The reason sniffing 0x399 on the Vehicle bus shows nothing is that 0x399 (DAS_status) isn't on the Vehicle bus — it's on the Party/Chassis bus. Continuous AP needs the DAS state (0x399 / 0x39B) plus the 0x3FD / 0x3EE AP-control frames, and those live together on the Party/Chassis bus — not the Vehicle bus, which carries body/switch traffic (windows, mirrors, 0x3C2, etc.).

The enhauto Commander can do continuous AP because it's multi-CAN and taps the bus that has the DAS frames. So to try it: put the device on the bus where 0x399 / 0x3FD actually appear — run a Listen-Only capture on each of your taps and look for 0x3FD; that's your AP bus — or use a dual-CAN board so one channel is on it.

[HamzaObaidat]

I don't think Continuous AP reads DAS state at all — that's why it works on the rear install with no CAN2.

It's open-loop: replay the drive stalk. Pre-Highland that's 0x229 GearLever = Full Down, pulsed twice for Autosteer (car in double-press mode). Trigger = sustained turn signal (0x249) turning off, speed-gated (0x257). All on the Veh bus. Only catch is continuing the live 0x229 counter + valid CRC instead of a stale replay.

enhauto's own docs back this up: rear/console install has no CAN2, Continuous AP still works there, and the CAN2-dependent stuff (Blind Spot, ISA mute) is front-only. So it can't be reading 0x399.

Is that how the Commander does it on rear — just 0x229 injection, no state read?

[fboulegue]

@HamzaObaidat well from what I saw it require Vehicle for the Double Click on Wheel & Chassis CAN for the AP State and Abort reason etc (no Party)

[HamzaObaidat]

I used to think that, but then I saw it works with rear installations too, which are just for VEH can

[hypery11]

That matches — thanks @fboulegue. So on your harness the scroll-wheel double-click AP engage (0x3C2) is on Vehicle, and the DAS AP-state / abort reason (0x399 / 0x39B) is on Chassis — not Party.

@HamzaObaidat — that's the key to your result: you were sniffing 0x399 on the Vehicle bus, but the DAS state lives on the Chassis bus, so of course nothing changed. For Continuous AP you need the bus carrying 0x399 / 0x3FD (Chassis on this harness) — capture Listen-Only on each tap and follow where 0x3FD shows up; that's your AP bus.