Maxus T90 EV (MT90)

Vehicle type code: MT90

The Maxus T90 EV module provides basic battery, temperature and lock/odometer integration using the vehicle OBD-II port and a single CAN bus at 500 kbps.

The implementation is still under active development; this page reflects the current feature set in the initial version of the module.

Hardware & Installation

Item

Notes

OVMS hardware

OVMS v3 module (or later)

Vehicle connection

OBD-II port using the standard OVMS OBD-II to DB9 data cable

CAN bus

CAN1 at 500 kbps, active mode

GPS / GSM antennas

Standard OVMS antennas (or compatible) as per OVMS documentation

Feature Coverage

Function

Status

Notes

SOC display

Yes

From OBD-II PID 0xE002 → ms_v_bat_soc

SOH display

Yes

From OBD-II PID 0xE003 → ms_v_bat_soh (with filtering)

Battery capacity

Yes

Custom metric xmt.b.capacity (fixed 88.5 kWh)

Odometer

Yes

From CAN ID 0x540 → ms_v_pos_odometer (0.1 km resolution)

Vehicle READY / ignition state

Yes

From OBD-II PID 0xE004 → ms_v_env_on and poll state control

Lock status

Yes

From CAN ID 0x281 → ms_v_env_locked (locked/unlocked)

Charge plug / pilot present

Yes

From OBD-II PID 0xE009 → ms_v_charge_pilot

Cabin / coolant temperature

Yes

From OBD-II PID 0xE010 → custom metric xmt.v.hvac.temp

Ambient temperature

Yes

From OBD-II PID 0xE025 → ms_v_env_temp

GPS location

Yes

Provided by the OVMS modem GPS (not vehicle-specific)

Speed display

No (vehicle-specific)

Only GPS-based speed available via OVMS core

Charge state / power / energy

No

Not yet implemented for this vehicle

Charge control (start/stop, limits)

No

Not yet implemented

Charging interruption alerts

No

Not yet implemented

Trip counters / consumption

No

Not yet implemented for MT90

TPMS

No

No TPMS integration yet

Door/window state

No

Only global lock/unlock is currently decoded

Remote lock/unlock control

No

Read-only lock status only

Pre-heat / HVAC remote control

No

Not yet implemented

Valet mode

No

Not implemented for this vehicle

AC / DC charge mode detection

No

Not yet implemented

Implementation Notes

  • The module derives from OvmsVehicleOBDII and registers CAN1 at 500 kbps in active mode.

  • Polling is done on ECU 0x7E3 / 0x7EB using extended OBD-II PIDs.

  • The poller currently defines three poll states:

    • State 0: vehicle off

    • State 1: vehicle on / driving

    • State 2: charging (reserved for future use)

  • In the initial implementation only the READY flag (PID 0xE004) is polled in state 0 to avoid keeping ECUs awake while parked; other PIDs are only polled when the vehicle is on.

  • The READY bitfield is used to drive ms_v_env_on and to switch poll states between 0 (off) and 1 (on).

  • Odometer is taken from CAN ID 0x540 using bytes [4..6] as a 24-bit little-endian value with 0.1 km resolution.

  • Lock status is decoded from CAN ID 0x281 (body control module) using byte 1 values:

    • 0xA9 → locked

    • 0xA8 → unlocked

    and mapped to the standard metric ms_v_env_locked.

  • Multiple sanity filters are applied to SOH and temperature PIDs to discard default/bogus values that occur when the vehicle is off or the ECU returns fallback frames.

Planned / Potential Extensions

The following features are candidates for future updates once the relevant PIDs and CAN messages have been fully reverse engineered:

  • Charge state / mode / power and energy counters.

  • Distinguishing AC vs. DC charging.

  • More detailed BMS data (cell voltages, min/max temperatures, etc.).

  • Additional body / door / window state.

  • Remote climate control and other remote vehicle actions, if feasible.