Gearbox ECU Override Unit

Judging by the search terms leading to the blog, as well as the popularity of the post Diagnosing the Transmission Anomaly, many of you are interested in our experiences trouble-shooting the problems we had with the transmission before leaving for Tunisia.

This weekend, we had a chance to take the Scania (EM-1) out for a drive, and we filmed a short sequence demonstrating the switches we installed on the gearbox monitoring unit that enable us to manually force a gear change if the ECU fails to send a command to the gearbox. The switches are mounted in parallel to the ECU, so that we can engage a gear if the ECU fails to do so. However, if the ECU has engaged the gear, then the switch will have no effect.

Since we first encountered the transmission problems only a few weeks before our departure to Tunisia, we did not have time to find a more comprehensive solution before the trip. This unit was designed to be an emergency override to make sure that we would not remain stuck in the desert in case of an ECU failure. Driving for an extended period of time while manually changing gears using the switches would not be easy, but in an emergency, it would be feasible.

We are still working on a more permanent solution and are investigating both repairing the ECU and designing a new micro-controller to replace it.  We’ll post an update once we’ve made more progress.