"Key in car" warning during braking

Tags: #connector

Total battery drain traced to Gateway/PKE corrosion. A more severe variant of Gateway-module trouble: complete overnight battery drain despite normal use, with dashboard warnings "System not passed check", "Brake system failure", and "EPB system failure" appearing together. Root cause: oxidized/corroded contacts in both the PKE module and the Gateway module — located on the right side of the cabin under the passenger leg area (near the passenger footwell pillar), with the Gateway box mounted above the PKE module. Because these two modules communicate with essentially all vehicle systems, a contact failure in either cascades into multiple, seemingly-unrelated error codes at once. Fix: disassemble both modules, clean oxidized contacts, resolder where needed. Also check fuse-panel voltage with the ignition off as part of the diagnosis. Alternative causes to rule out first: a genuinely dead battery, a non-charging alternator, or loose battery terminal connections ^{12345678 9101112}.

Symptom: a "key in car" warning icon flashes on the dash during braking ¹³. Some owners consider intermittent flashing "normal enough" that they've grown used to it, especially when the key is left in a jacket pocket rather than a trouser pocket, and it happens even with a fresh key-fob battery ¹⁴¹⁵¹⁶.

Possible causes, from most to least commonly cited. (1) Dead or weak key fob battery — the first thing to check/replace ¹⁷. (2) Oxidized or damaged key contacts — test with a second key fob to isolate whether the problem is the key or the car ¹⁸¹⁹. (3) The Gateway module — a small black box mounted above the PKE control block on the passenger side — has a loose connector ²⁰²¹. One owner's root cause: he had physically forgotten to reconnect this Gateway module connector after reassembling the PKE system during other work — power to that block was simply not connected ²²²³. (4) General PKE control-module failure.

Diagnostic steps. Test a second key fob first, since key-side issues (oxidized contacts, dead battery) are the simplest and most common cause ¹⁸¹⁹. If the issue persists across keys, check that the Gateway module's connector (located above the PKE block, passenger side) is properly seated ²⁰²². Disconnecting the car battery for about 10 minutes to reset the system helped resolve the issue for at least one owner, independent of the connector check ²⁴.

Media

PKE and Gateway module location in the vehicle, passenger footwell area

Electrical schematic showing PKE/Gateway module communication architecture

Fuse panel with voltage test points referenced during this diagnosis

Additional photo of the PKE/Gateway module area

Photo showing the PKE control block and the Gateway module's position in the dashboard, passenger side

Related pages

• Airbag warning light stuck on — battery reset
• Headlight adjustment and common faults
• EPB (electronic parking brake) issues
• Immobilizer module — location and water damage
• Rear backup camera failure diagnosis

Sources

This page is compiled from 24 community messages. Every fact carries a numbered reference to its original author and message.

Last updated: 2026-07-25