The idea
A modified car sets codes more often than a standard one, and usually when the scan tool is at home. The ECU knows exactly which code is stored. The dash has a lamp, a tachometer needle and a small screen. All that was missing was software connecting them.
How the driver uses it
- Read: with the engine off, hold CANCEL on the cruise stalk for three seconds. The check-engine lamp blinks out the stored codes.
- Scroll: the codes also appear on the i-MID screen, where SET and RES step through them.
- Clear: press MAIN three times. The tachometer needle makes a single sweep to confirm the codes are cleared.
An earlier version spelled the code digits out on the tachometer needle. It worked, and it was on the car from 12 November 2026, but the screen turned out to be the better display, so the needle now only confirms a clear.
Why it is harder than it sounds
None of this exists in the factory software. The instrument cluster and the i-MID are separate computers that listen to messages from the ECU. To put a code on the screen we had to work out which messages those units accept and what they draw in response, then write code inside the ECU that composes those messages only when the engine is stopped and the driver has asked.
The stalk buttons already had jobs. Every gesture had to be one that does not occur in normal driving, and the display only runs with the engine stopped.
Our own hardware reports through it too
The wastegate controller we built reports its faults to the ECU, which stores them as standard trouble codes. They appear in this display, and on any ordinary scan tool, alongside Honda's own.
Status
The lamp and tachometer version went on the car on 12 November 2026. The i-MID version followed on 13 November. One of the new wastegate codes currently sets a second factory code with it; the correction is built and waiting for the next flash.
Have a car the usual tools cannot touch?
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