Hi everyone, hoping someone here has dealt with this before on an AK550.
My Kymco AK550 has been intermittently throwing a P0121 code.
Diagnostic says:
Throttle/Pedal Position Sensor “A” Circuit Range/Performance
And in the Kymco service manual it specifically mentions:
“abnormal adapted value”
What’s strange is the behavior:
* the engine light appears mostly on cold starts or after the bike has been sitting for a few hours
* after the 5th start in a row the warning disappears by itself
* bike generally rides normally
* charging voltage and resting battery voltage are both good
* but during cranking voltage sometimes drops to around 9.9–10.5V
I already checked live TPS data and:
* TPS value at idle is stable around 18%
* values move smoothly with throttle input
* no obvious jumping or flickering
I also recently installed a new battery about 3 months ago (advertised 340 CCA), but my tester estimates around 270 CCA now.
I’m trying to understand whether this is more likely:
* TPS sensor itself failing
* throttle body issue
* adaptation/relearn issue
* voltage sensitivity during startup
* connector/wiring issue
* something common on AK550s
Has anyone here had:
* P0121
* “abnormal adapted value”
* cold-start engine light
* intermittent TPS errors
…and actually solved it?
If yes:
* what was the final fix?
* TPS replacement?
* throttle body clean/relearn?
* battery/ground issue?
* connector corrosion?
* dealer ECU reset?
Any info would really help before I start replacing expensive parts blindly 😅
