28/05/2026
When is a faulty wire not a faulty wire……..
This Disco 5 came in initially for a engine management light but when dropped in we were asked of we could also investigate the SOS warning on the dash and the radio intermittently not emitting sound.
The EML was a straight forwards job. The SOS was logging faults with the internal microphone and call button both being shorted to ground. These items are both up near the interior light and are common failures when a windshield has leaked, but this wasn’t the case. Going off the fault descriptions the manual suggested it was a wiring fault. It would also cause the intermittent radio failure as when the SOS system is in operation the infotainment system is muted. And as the car thought it was nearly continuously in operation this confirmed the last customer concern.
All Components were checked as well as the wiring which were all fine. The last part of the system was the Telematics module (TCU) which is basically the car’s modem connecting it to the internet and other services. It has several functions but one is its ability to remotely start the car from the JLR app.
This being so it makes the module part of the cars immobiliser system. With us being SERMI approved we were able to program a new module and get the car back on the road.