Fault in the valve control loop
Published: 5 October 2024 · Status: Resolved in firmware 2.0.1 · Last reviewed: 2026-08-07
Affected
Devices running firmware older than 2.0.1 that drive transmission valves directly — that is, the standalone transmission controller running any of the direct-control drivers. A gateway installation, where the factory transmission control unit drives the valves, is not affected.
What happens
The valve control loop is what holds a solenoid at the current the strategy asked for. A fault in that loop shows up as pressures that do not match what was commanded, which reaches the driver as shift quality that is wrong in ways the configuration does not explain.
I did not publish the specific failure mode at the time, and I am not going to reconstruct it now from memory — the original notice recorded that a fault had been found and that a fix was in progress, and nothing more. If you are on affected firmware and chasing unexplained shift behaviour, treat the version as the more likely explanation than your calibration.
Why
A defect in the firmware's valve control loop. Not a configuration error, and not something a parameter change compensates for.
What to do
Update to firmware 2.0.1 or later.
After updating, re-run the adaptations. Corrections learned while the control loop was misbehaving were learned against wrong behaviour, and they stay learned until they are reset — see Troubleshooting.
Status
Resolved in firmware 2.0.1, which lists "Improved reliability of valve control" under Transmission support in its release notes.