What does it mean?
B1459 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Telematics Mirror Control Circuit Low .
Symptoms
- Buttons in the rear-view mirror, such as the assistance or emergency call keys, do not respond
- Indicator LEDs in the mirror stay dark or flash abnormally
- Hands-free microphone in the mirror is dead or very quiet on outgoing calls
- Telematics services report themselves as unavailable on the display
- The mirror's other functions may still work, which makes the fault look like a service subscription problem
- Code stays stored and returns after each ignition cycle
Likely causes
- Short to ground in the wiring between the telematics module and the mirror head
- Water leaking down from the windscreen or roof console into the mirror connector
- Harness pinched in the headliner or A-pillar after windscreen, headliner or camera bracket work
- Aftermarket dash camera or accessory spliced into the mirror feed and loading the circuit
- Corroded or spread terminals in the mirror connector, dropping the line voltage
- Internal fault in the mirror assembly pulling its control line low
- Failed output driver in the telematics or communication module
How to fix it
- Read the body and telematics codes and note whether the fault is current or historic
- Look for aftermarket wiring at the mirror base first, since taps for cameras and detectors are a common cause
- Lower the mirror trim cover, unplug the connector and inspect it for water tracks, corrosion, green pins and pushed-out terminals
- With the mirror unplugged, measure the resistance from the control line to ground; a low reading proves a harness short
- With the mirror connected, back-probe the control line and compare the voltage against specification while operating the mirror functions
- Check the ground for the mirror circuit and measure its voltage drop
- Follow the loom along the headliner and A-pillar for a pinch point, then repair and re-route it away from trim fasteners
- Replace the mirror assembly only after the wiring is proven good, and treat the telematics module as the last step