BMW 138102: Exhaust Flap Short to Ground
BMW code 138102 means the DME detected a short to ground on the electric exhaust flap actuator circuit. It is most commonly seen after an aftermarket cat back or axle back exhaust reuses the original valve controller, but a failed actuator or damaged wiring can cause it too, so a proper diagnostic read is needed to confirm which.
Quick facts
- System
- Exhaust / Muffler Flap Control
- Severity
- Low
- Can you still drive?
- Yes, safe to drive
- Applies to
- F and G series BMW with an electric exhaust flap actuator, DME reported. Confirmed on G20 330i (2021) and F87 M2 Competition (2021); the same actuator family is used across G20,...
Also shown by some scanners as: 0x21BC6, Exhaust flap activation short circuit to ground, 138104, 138A04
Symptoms
- Check engine light on with the exhaust flap fault stored, often while the flap still audibly opens and closes
- Exhaust note stuck loud or stuck quiet because the flap no longer changes position
- Rattle or drone from the rear silencer area
- Code returns immediately after being cleared
- Fault appears right after an aftermarket cat back or axle back exhaust was fitted reusing the original valve controller
Common causes, most likely first
- 1
Aftermarket or cat back exhaust installation disturbing or reusing the original valve controller and its wiring
Most common trigger reported alongside this code
- 2
Short to ground in the actuator wiring or connector, including a chafed loom near the muffler
- 3
Failed exhaust flap actuator or valve controller motor
- 4
Corroded or water damaged connector pins at the actuator
- 5
Heat damage to the harness running along the rear silencer
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Frequently asked questions
Can I still drive with code 138102?
Yes, it is safe to drive. A failed exhaust flap actuator only changes the exhaust sound and does not affect engine performance, safety or reliability, though the check engine light will stay on until it is fixed.
Does this always mean the actuator itself is faulty?
Not always. It is often triggered by an aftermarket exhaust reusing the original valve controller, or by a chafed wire or damaged connector rather than the actuator itself. A proper diagnostic read is needed to pin down the exact cause before assuming the part is bad.
How do I fix it, what does it need?
After confirming the cause with a diagnostic read, the fix path is usually a replacement exhaust flap or muffler flap actuator (valve controller), a repaired section of the rear harness with connector, or in some cases the rear silencer assembly if the flap is seized in the pipe. WhatsApp us the code and car model for stock and today's price.
Which BMW models does this code apply to?
This applies to F and G series BMW fitted with an electric exhaust flap actuator, DME reported. It has been confirmed on the G20 330i and F87 M2 Competition, and the same actuator family is used across G20, G22, G30, X3 and X4 from roughly 2016 onward.