Maverick Immobilizer Fault

An immobilizer fault on a Maverick, eh? Sounds frustrating. The symptoms you're describing definitely point to a potential key/immobilizer problem. You mention a possible key programming issue; have you tried using a spare key, if you have one? Does the security light on the dash behave normally (illuminating briefly then going out) or does it flash continuously, even when the key is in the ignition?

I did try the spare key, and it's doing the exact same thing. As for the security light, it stays on solid when I put the key in, it does not flash, what does that indicate?

Ah, a solid security light, that further confirms our suspicions about the immobilizer being the culprit. It appears the key is not being correctly recognized by the system. While there are some 'immobilizer bypass' methods floating around online, I cannot, in good conscience, recommend them, as they often compromise the vehicle's security. Given that both keys are exhibiting the same issue, and the light stays solid, it is most likely a key programming fault and my recommendation would be to have a workshop check the remote start or ignition control.

Took it to the shop, and you were spot on. Turns out the key needed to be reprogrammed. Cost me 45€, but at least it's running again. Thanks again for your help!