The "ECU stop" single when using J1939 and EMS 2 on the Volvo 12 Litre range (and indeed on the other engines that use EMS 2) is an essential part of the safe setup for these models.

The engine, which most controllers people use (certainly the Deep Sea range used by Welland) start and stop the engine using the J1939 data link.

What happens if the link fails? This is the most important situation for "ECU STOP" signal, as it is the only way to stop the engine electronically.

On the 7, 9 and 16 litre models that use EMS 2, you can stop the engine by powering the ECU stop wire. (It is the green wire coming from the Volvo EMS 2 extension harness).

On 12 Litre Models you must remove the voltage on these lines, after having it initially powered up to start.

It is advised to check this as part of the test on the engine.