Overview — central-lock plus retractable power-step
Heavy-truck cabs and large coach / MPV platforms sit on tall chassis — the climb-in gap from ground to door-sill can be 700-900 mm, which is a non-trivial step for the driver every time they get in or out. The standard solution is a retractable side-step (power-step) motor on each side of the cab that extends automatically when the door unlocks and retracts automatically when the cab locks, removing the gap on entry / exit but staying tucked away during driving for ground clearance and aerodynamics.
The EBX-2207 is the dedicated controller for this function combo. One ECU owns both the central-lock motor drive (lock / unlock / anti-theft horn) and the paired power-step motor drive (extend / retract), with the two function blocks tied together so the step automatically tracks the lock state. The 4-switch matrix (indoor extend, indoor retract, outdoor extend, outdoor retract) gives the operator manual override — useful when loading the cab while the door is open but the lock is not in the unlock state, or when wanting to retract the step before parking next to a kerb.
The single 20-pin AMP connector face keeps the harness simple, the PA66-GF15 housing handles the long-vibration heavy-truck profile, and the ≤ 1.5 mA quiescent current is low enough that the controller can stay armed for the multi-day parked periods that happen between long-haul shifts without draining the battery. An optional 6-button PKE keyfob pairs with the controller for the standard lock / unlock / boot / panic-horn function set typical of a modern fleet keyless-entry programme; the LIN reserve line on pin 20 lets a future revision tie into the host vehicle's LIN bus for step / lock state telemetry.
Function blocks walk-through
1. Central-locking (lock + unlock + anti-theft horn)
The central-lock sub-system uses pins 2 (central-lock close drive) and 3 (central-lock open drive) on the connector face to drive the central-lock motor pair through external relays, with the central-lock switch inputs on pins 11 / 12 capturing the operator's lock / unlock request from the door-card switch or the PKE keyfob. Pin 1 carries the horn output for the anti-theft horn-chirp confirmation on lock / unlock. The lock-state machine ties directly into the power-step state machine — on unlock the controller starts the step-extend sequence; on lock the controller starts the step-retract sequence.
2. Retractable power-step (extend + retract + 4-switch override)
The power-step sub-system uses pins 10 (extend drive) and 14 (retract drive) on the connector face to drive the power-step motor pair through external relays. The 4-switch override matrix splits the manual control between the indoor switches (operator already in the cab, wants to retract or re-extend the step manually) and the outdoor switches (operator at the side of the cab, wants to extend the step to climb in or retract before walking away):
- Pin 8 — indoor extend switch: driver-side cab switch, extends the step when pressed
- Pin 19 — indoor retract switch: driver-side cab switch, retracts the step when pressed
- Pin 13 — outdoor extend switch: kick-sensor or door-frame switch, extends the step when pressed by the operator outside the cab
- Pin 17 — outdoor retract switch: kick-sensor or door-frame switch, retracts the step when pressed by the operator outside the cab
The state machine prioritises a manual override over the automatic lock-tied behaviour for a short configurable timeout window, then returns to automatic behaviour on the next lock / unlock event.
3. Optional PKE keyfob
The optional 6-button PKE keyfob is paired with the controller at provisioning. The standard six-button layout: lock, unlock, boot / trunk-release, panic-horn (long-press), plus two programme-defined keys for custom function (typical use: cab-light-on / cab-light-off, or step-extend / step-retract direct). The controller stores the keyfob ID in non-volatile memory and supports re-learn / clear-all sequences for fleet redeployment.
4. LIN reserve line
Pin 20 carries a LIN bus reserve line. The current firmware does not require the LIN line to be active; the line is reserved for a future revision that ties into the host vehicle's LIN bus, letting an upstream BCM / cluster subscribe to the step / lock state telemetry for in-cab display.
Engineering details
- Central-lock + power-step on one ECU — replaces a typical two-box arrangement (central-lock controller + separate power-step driver) with one ECU and one 20-pin harness
- 4-switch manual override matrix — indoor / outdoor + extend / retract gives the operator independent manual control while keeping the automatic lock-tied default behaviour
- ≤ 1.5 mA quiescent current — ultra-low standby draw lets the controller stay armed across multi-day parked periods between shifts without measurable battery drain
- PKE keyfob ready — optional 6-button keyfob with the standard lock / unlock / boot / panic + two custom keys; controller learns and stores the keyfob ID in non-volatile memory
- LIN reserve line on pin 20 for future BCM / cluster telemetry integration
- 20-pin AMP sealed connector — AMP 368511-1 / 175785-1 industry-standard automotive connector with wide global availability for the matching wire-side housing, terminals and seals
- PA66-GF15 housing — 15 %-glass-filled polyamide for stiffness and thermal stability under the typical under-cab placement profile of the heavy-truck application
- Compact 95 × 92 × 24.5 mm body — takes a small footprint on the cab-floor / kick-panel bracket close to the power-step motor and the door-frame central-lock branch
Mechanical layout and connector pin-out
Companion remote and housing stack-up
Comparison with the related Youlai cabin / body controllers
| Model | Central-lock? | Power-step drive? | One-button-start? | Connector |
|---|---|---|---|---|
| EBX-2207 | Yes | Yes (extend + retract + 4-switch override) | — | 20-pin AMP |
| EBX-2405 | Yes | — | Yes (one-button-start sequencer) | 26-pin TE |
| EBX-2315 | Yes | — | — | Single housing |
The EBX-2207 is the right choice when a programme wants both central-locking and retractable power-step on a single 20-pin ECU, with the lock state automatically driving the step extend / retract behaviour. For an entry-trim programme that wants central-locking with one-button-start and turn-signal / DRL instead of power-step, look at EBX-2405; for a programme that wants central-lock combined with electric-window and mirror-adjust, look at EBX-2315.
Manufacturing & testing
Built under IATF 16949 with APQP project planning and a PPAP package available for OEM programmes. Every unit is end-of-line functional-tested before packaging — the central-lock close / open drive outputs, the power-step extend / retract drive outputs, the 4-switch override matrix (indoor / outdoor × extend / retract), the IGN input, the lock-state → step-state tied behaviour (automatic step extend on unlock; automatic step retract on lock), the ≤ 1.5 mA quiescent current with the controller in armed sleep, the PKE keyfob pairing sequence and the LIN reserve-line continuity are all checked.
How to ask
The EBX-2207 belongs to the Smart Control Modules family. To request the harness drawing, the power-step motor compatibility list, the PKE keyfob SKU, the LIN-bus firmware variant or a PPAP package, please use the contact page with your target vehicle programme, expected annual volume and key technical requirements (central-lock motor model, power-step motor model + extension travel + drive current, switch ergonomics for the 4-switch override matrix, IP rating). Drawings welcome.
