B0450 code meaning
Microphone Circuit
What B0450 means
The code B0450 is absent from the publicly accessible J2012 lists, and no carmaker publishes it, so it remains unverified. Its title covers the hands-free microphone line. The module puts a bias voltage on the signal wire and reads speech back on the same wire. On the 2011 Saab 9-5 and its 9-4X sibling the OnStar module logs B2455 once the signal wire has been broken, grounded or tied to supply, or the low-reference return has lost contact, for 10 s; the status LED turns red and the other party cannot hear the caller. Audio converters like TI's PCM6240-Q1 supply a 5–9 V bias and flag open or shorted inputs and shorts to ground, bias or battery. Calls and voice control still start, but the far end hears nothing. Pairing problems belong to B0440.
B0450 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of B0450
- Caller cannot hear the driver during hands-free calls
- Voice control does not react to spoken commands
- Emergency call or telematics status lamp shows a fault
Common causes of B0450
- Most likelyMicrophone in the headliner or mirror failed
- PossibleMicrophone wire pinched or broken in the headliner or A-pillar
- PossiblePlug at microphone or module loose or corroded
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
MicrophoneInfotainment moduleTelematics module
What each part of B0450 means
| B | Body system: airbags, seat belts, power seats, lights and climate control. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 50 | The exact fault in that area. |
What to do next
- Note B0450 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about B0450
What does B0450 mean?
B0450 means "Microphone Circuit". The code B0450 is absent from the publicly accessible J2012 lists, and no carmaker publishes it, so it remains unverified. It is a generic code, so it means the same on every make.
Is it safe to drive with B0450?
B0450 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will B0450 fail an emissions test?
B0450 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is B0450 to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will B0450 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.