U0240: Lost Communication With Entrapment Control Module B
What to do
The car drives normally. Powered closures will lose their unattended operation and move only while a switch is held.
On a vehicle with powered sliding doors or a powered tailgate, take this seriously rather than treating it as a lost convenience. This module supervises the protection that stops a heavy powered door closing on somebody — and unlike a window, those close on an opening people walk through. If children use those doors, supervise them until it is fixed.
If this followed a battery change or a flat battery, the closures may just need re-initialising — see U0239, it is free and often the whole fix.
Otherwise the wiring is the usual suspect, and on a sliding door especially: its loom travels the whole length of the door's track every time it opens, which is much harder on wiring than any hinged door.
What this code means
The second entrapment control module has stopped being heard from. The function and the protective-restriction reasoning are at U0239.
A second entrapment module means the vehicle has enough powered closures to need the supervision split, which in practice means a large vehicle: powered sliding doors, a powered tailgate, multiple roof panels, or rear closures on a van or people carrier.
That population changes the risk rather than the diagnosis, and it is the reason this page exists separately. A window closing on a finger is painful. A powered sliding door has the mass and the leverage to do considerably more harm, and it closes on an opening that people walk through rather than reach into — which is precisely why these vehicles carry more entrapment supervision, not less.
So the advice to treat the lost protection seriously is stronger here. Where the affected closure is a sliding door or a tailgate, and it can still be operated at all, it should be treated as an unsupervised mechanism until it is fixed — worth knowing on a family vehicle where children use those doors.
Diagnostically, the pattern check from U0202 applies: one entrapment module silent while the other reports normally localises the fault to that module's own branch, while both going quiet together points at a shared supply or the gateway.
The sliding-door harness caution from U0203 applies to anything this module supervises on such a door — the loom travels the full length of a track and is the harshest wiring environment in the block.
Likely causes
Start here
- Broken wire in the door harness boot · moderate
- Battery disconnected or module reprogrammed · easy
- Damaged wiring harness · moderate
- Corroded or loose connector · easy
Less common
- Failed power or earth supply to the module · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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