23/11/2024
Had an interesting one the other week. A customer contacted me about their VW Amarok having intermittent issues with check engine lights and a trippy dash.
Given that it was the main car for the family (and maybe a little because I have a thing for Volkswagen's 🤭), I managed to find some time in my busy schedule to have a look.
The initial health report came back with multiple codes relating to the loss of communications between the various modules. Using the information from the fault codes, as well as the wiring schematic for the CAN circuits, I was able to work out that there had been a break somewhere in the circuit leading to the dash cluster. I just had to find it.
I logged the codes, cleared everything, and ran the health report again to get a base line to work from. With no codes logged, I went to start the vehicle, and as soon as I pushed the clutch in, everything went haywire. Clutch out, normal. Clutch in, problem.
So I poke my head under he dash, and straight away, I can see an issue. The main harness had come away from its retaining clips and was sitting on top of the clutch pedal bracket. As the clutch was pushed in, the pedal arm/spring (red arrow) would contact the harness. Not much, but enough that several years of changing gears wore through the outer fabric tape and through a wire for the CAN network (red circle)
With the clutch released, the damaged wires were able to touch just enough to allow signal to the dash and correct operation. With the clutch in, the pressure on the loom would push the 2 ends of the wires apart. When this occurred, the dash would illuminate all warning lights, and with the loss of signal, the gauges would drop to 0.
After gaining better access to the loom and damaged wire, I was able to confirm that it was the wire on the CAN low circuit that supplied the dash cluster. Thankfully, I was able to coerce enough free to allow a solid repair.
Fault codes were cleared, a health report ran, and we were good to go. I refurbished the loom with some OE spec fleece tape, and it looked good as new.
A quick drive and test of all functions, and it was happy days. 🤙
All in time for school pick up too.