10/11/2025
🚗 Another tricky electrical fault fixed today at Apex Auto Tech! ⚡
This Hyundai came in with no engine communication, a dead rev counter, warning lights across the dash, and intermittent heavy steering.
After scanning the vehicle, we found multiple CAN network and engine speed signal faults stored in the steering and ABS systems. Communication with the ECU wasn’t possible – even with different diagnostic tools – although the engine would still run. We also noticed flickering headlights and a few other strange electrical behaviours.
📈 Using the oscilloscope, we could see the CAN signal at the ECU was badly distorted and appeared to be shorting between the two wires on that network. At this point it becomes a process of elimination – checking the network layout, then disconnecting modules one by one while crossing our fingers it’s not a wiring rub buried behind the dash (those ones aren’t fun to find!).
💥 The culprit? The rear reversing camera!
It was heavily corroded and shorting out the CAN network – which stopped the car communicating with the ECU and caused all the weird issues. Why Hyundai decided to put the camera on the same network as the engine ECU… we’ll leave that one to their engineers. 😅
Once disconnected, all the faults cleared, the dash lights went out, and the steering returned to normal.
✅ The car’s now running perfectly – just without a reversing camera, since a replacement is almost £600 and the customer was happy to keep the £600 instead!
We’ll include some oscilloscope captures below showing the CAN signal before and after the repair 👇
