Mercedes-Benz B154E13: Antenna Module Open Circuit, Key Not Detected
B154E13 means the Keyless Go antenna module circuit is showing open, so the car cannot see the key. It is usually the antenna module itself or a broken wire or connector feeding it, though a weak fob battery or low car battery can mimic the same symptom.
Quick facts
- System
- Keyless Go / Antenna Module
- Severity
- Moderate
- Can you still drive?
- Short drives only, diagnose soon
- Applies to
- Keyless Go and Keyless Start equipped cars. Reported on CLA 250, Sprinter (2020) and C-Class C200, and the same B154E antenna module family is discussed on GLE 350 and CLS. No published source gives a full chassis list, so treat it as any modern Mercedes with Keyless Go rather than a fixed model set.
Also shown by some scanners as: B154E, B154E-13, B154E1
Symptoms
- Key not detected message on the dash
- Keyless entry not working, touching the door handle does nothing
- Have to press the fob buttons to unlock instead of just touching the handle
- Engine will not start on the button until the key is held at the designated console spot
- Fault comes and goes, working some days and not others
Common causes, most likely first
- 1
Failed Keyless Go antenna module or antenna control module
Most common finding once the antenna module circuit is confirmed open
- 2
Open circuit in the wiring or connector between the control unit and the antenna module, often at a door hinge loom
Common on cars with flexing door looms over years of use
- 3
Corroded or loose pin at the module connector
Common on cars that have had water ingress in the door or boot
- 4
Weak key fob battery or a fob that has lost sync
Cheap first check that can mimic key not detected before any module is condemned
- 5
Low vehicle battery voltage causing intermittent Keyless Go dropouts
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Frequently asked questions
Can I still drive with B154E13 showing?
Yes, the car still drives. The real risk is being locked out or unable to start away from home, since the convenience keyless path has failed. Use the emergency key blade and the console start position as a backup, and get the antenna module circuit checked before a long trip.
Does this always mean the antenna module needs replacing?
Not always. The antenna module is the most common finding, but wiring breaks, corroded connectors, a weak fob battery, or even low car battery voltage can all trigger the same open circuit reading. A proper diagnostic read is needed to confirm which one before any part is replaced.
What does fixing B154E13 involve?
Depending on what the workshop's diagnostic read finds, the fix usually centres on the Keyless Go antenna module or antenna control module, or a wiring and connector repair between the control unit and the antenna. Sometimes it turns out to be as simple as the fob battery. This is workshop diagnostic and repair work, not a DIY job. WhatsApp us the code and car model for stock and today's price.
Which Mercedes models does B154E13 apply to?
This applies to any Mercedes fitted with Keyless Go and Keyless Start. Sightings include CLA 250, Sprinter 2020, C-Class C200, and the same antenna module fault family discussed on GLE 350 and CLS. There is no fixed chassis list, so treat it as a possibility on any modern Keyless Go equipped Mercedes.