Every mechanic has a car that gets under their skin, the one that seems to fight back at every turn no matter how methodical you are. For Jooshy, host of Jooshy’s Workshop, that car is an early-generation Porsche Cayenne V8 with 141,740 miles on the clock and nearly every warning light on the dashboard lit at once.

The Cayenne rolled in sounding like it was running on four cylinders instead of eight, with the ABS, traction control, airbag, engine management, brake proportioning, and TPMS lights all fighting for attention on the same dash. Jooshy went in hoping for one clean explanation, a single fault taking every system down with it. What he actually found was a car that had already been fought over by someone else, and lost.

By the end, that hope had curdled into something closer to exhaustion. Hours of tracing wires, chasing dead ends, and circling back to conclusions he’d already ruled out left him with a car still sitting dead in the shop and no answer to show for it.

Someone had already been here, and it showed

The first walk-around told its own story, and not a reassuring one. Non-factory electrical tape sat in the fuse box next to a mystery wire feeding a relay with no obvious purpose. An aftermarket push-button starter had been jammed in near the steering column, replacing the factory key ignition outright. Heat-shrink solder splices ran through the main harness, the kind of repair Jooshy said flatly he never trusts to actually carry current the way it’s supposed to.

An OBD scan reached exactly two modules, the engine and transmission, and went silent on everything else. Add in the mold and the smell under the carpets, “stinks like a pond” in his own words, on a platform known for sunroof-drain water ingress, and the diagnosis was already turning into an archaeology project: water damage patched over by someone who clearly did not understand what they were touching.

Chasing power, hitting walls, chasing it again

Jooshy tried to stay disciplined about it, working power first and communication second, the way any good diagnosis should go. Pulling both front seats and the carpet exposed the transmission control and transfer case modules underneath, along with more mold and, for good measure, a pound fifty in loose change. Every fuse he tested on both sides of the car came back powered correctly, which should have been progress. Instead it just meant the easy explanation was gone.

That pushed him into the CAN network, and this is where the video starts to feel less like a repair and more like a fight. At the airbag module, power and ground both checked out fine. But the CAN bus wiring itself returned resistance in the mega-ohm range, absurdly far outside anything workable, while the same test at the OBD port gave him nothing at all. Not a bad reading. Nothing.

One splice explained itself. The other one buried him

Behind the dash, Jooshy did find something concrete: a scotch-lock splice bridging the ignition switch straight to the starter relay socket, completely deleting the factory relay. That explained the fuse that kept blowing, at least. One small win.

The CAN fault was not so generous. Digging through a bundle of old repairs, he found separate CAN circuits spliced together into a shared cluster, then kept finding more, each one crossed with another, effectively stacking multiple independent networks on top of each other and scrambling every resistance reading he’d taken. By his own account he spent real time here going in circles, convinced it was the wiring, then convinced it was power, then back to the wiring again, before finally separating the pairs and getting a sane reading back.

From there he found a workaround, bridging the drive CAN network to the diagnostic CAN network at the instrument cluster, since early Cayennes route the gateway module through the cluster itself. It worked. ABS and airbag communication came back for the first time in the whole video, and for a moment it looked like the nightmare was over.

The fix that should have worked, and didn’t

Riding that momentum, Jooshy installed a secondhand replacement cluster, sourced for £120 by the car’s owner, and swapped the aftermarket start button back out for a proper factory relay. Every diagnostic thread pointed to this being the moment the car came back to life.

It wasn’t. The dash lit up, the car chimed at him, and the engine still refused to crank. No amount of testing changed that. Every wire break had been repaired. Every CAN segment sat at a clean 60 ohms. Every power and ground checked out exactly where it should. And the car sat there anyway, just as dead as when the seats first came out.

When there’s nothing left to test

That’s the note the video ends on, and Jooshy doesn’t dress it up. He’s out of ideas, out of tests, out of the kind of diagnostic tools that would let him go further without factory Porsche software. He says as much on camera, plainly admitting defeat after doing everything he knows how to do. The Cayenne goes back to its owner exactly as broken as it arrived, and the comment section becomes the last diagnostic tool left on the table.

There’s a particular kind of frustration in a repair video that doesn’t end in triumph, the sense of a mechanic who did everything right on paper and still lost to a car that simply wouldn’t cooperate. A Cayenne rewired and patched by someone with less skill than the person now trying to undo it left Jooshy chasing a fault that, for now, refuses to explain itself.