M400 ECU broken?

[Mauritz Lindqvist]

Hi all, a first time poster in this forum from Sweden here.

I have diagnosed a suspect broken M400 and are looking for some advice, before we send it away for repairs.

Yesterday I helped a friend with his Opel Astra Kitcar, that stopped during a winter rally two weeks ago. The engine died while he waited for the marshals registering his time at the end of a stage. The engine did restart a few times so they could move the car, but it did not run well.

Now the engine won't start at all. Sometimes when turning on the ignition, the cooling fan starts and I will not stop until you turn off the ignition. Sometimes the fuel pump runs for a few seconds, but delayed 5-10 seconds after ignintion on. No sensor data from engine is updated on the dash.

The car is equipped with a M400 engine ECU and an ADL Dash, connected by a short CAN-cable with one-100R terminating resistor in the midle.

Using an UTC USB to CAN adapter, we can´t connect to the M400 ECU. Connecting to the ADL Dash works fine and there are no problems to get configuration, logs, etc from it.

We had a spare set of AMP Superseal Connectors availiable for the M400, so we connected the engine ECU with only + 12V, earth and the four cables required for CAN and diagnostic socket. But still no luck to communicate with the M400.

We borrowed another M400 and plugged it to the Opel Astra, and it connects fine to the PC so we can look at the data in the borrowed ECU.

We have also,
* Measured the + 5V and + 8V power outputs, and they are good.
* Measured the CAN-bus lines with an oscilloscope. Lots of messages with the ADL + M400, no messages with only the M400 connected. But the voltage levels rises to 3.5V (as it should when there is no messages) on both CAN HIGH and CAN LOW with only the M400.

Any thoughts of what might happen with the M400? I thinks the delayed fuel pump start might be a qlue.

We are going to send the M400 to an engine tuner who knows Motec ECU's well later this week, so he can take a look at it.

Kind regards,
Mauritz Lindqvist
Sweden