A while ago I hooked a CAN logger to a friends CRZ, and reverse-engineered the CAN bus on both the vehicle CAN (accessible via the diagnosis port) and the secondary IMA CAN bus (requires hooking up to the cables directly).
I did some test drives and based on the vehicle behavior reverse-engineered what the CAN bits stand for. I hope it helps for your projects!
Vehicle CAN
The vehicle CAN bus contains all the “major” information in the vehicle, e.g. wheel speed encoders, engine RPM, switch states, headlight status, etc.
| Message ID | Position (bit) | Length (bit) | Description |
| 0x13F | 8 | 16 | ThrottlePosition raw |
| 0x13F | 40 | 32 | ThrottlePosition counter |
| 0x164 | 0 | 8 | Headlight switch |
| 0x164 | 48 | 16 | Vehicle speed |
| 0x17C | 24 | 16 | Engine RPM |
| 0x191 | 1 | 1 | Transmission reverse SW |
| 0x191 | 2 | 1 | Transmission neutral SW |
| 0x374 | 32 | 8 | Trunk open |
| 0x136 | 8 | 8 | VTEC SW |
| 0x136 | 0 | 8 | fuel cutoff |
IMA CAN
The IMA (Integrated Motor Assist) CAN bus contains information specific to the hybrid system.
| Message ID | Position (bit) | Length (bits) | Description |
| 0x111 | 8 | 16 | IMA Motor RPM |
| 0x169 | 8 | 16 | IMA motor current (mA) |
| 0x231 | 24 | 16 | IMA SOC (State Of Charge) |
