Ford Ranger Pricing and Specs

With any luck, this will be a simple case of a failed micro-switch in the door jamb. If the switch fails, the car thinks the door is open and, therefore, triggers the warning light as well as switching on the interior light, which is normal when the door is open.

You need to start by seeing if you can isolate which of the four door switches is playing up, and go from there. Replacement is simple and shouldn’t cost much.

If you’re unlucky, though, this sort of behaviour can be caused by a failed (or failing) body computer which controls all these functions and many more on a modern car. An auto electrician should be able to diagnose this pretty quickly.

This make and model has not been without its transmission problems, ranging from minor to major failures at relatively low mileages. The D solenoid is one of the units that effects the gearshifts in this transmission, and it can throw a fault code for a variety of reasons. Those start with a dirty filter in the transmission, a failed pump, failed valve body, a problem with the solenoid itself or its wiring or even a dud computer that controls the transmission.

A transmission specialist will be familiar with this transmission and the common causes of its throwing a D-solenoid fault code. With that knowledge, a correct diagnosis will be much easier and quicker.

Since you’ve replaced the turbocharger and the boost controller, we can rule those out. But could the problem be something much simpler?

It’s possible that the plastic trunking that takes the compressed air from the turbocharger to the engine’s intake has split. When that happens, boost pressure is lost, the boost sensor detects the low boost and winds up the turbocharger to compensate and you have an on-paper overboost situation.

Then, once you’re beyond idle, the leak becomes even worse and the computer simply runs out of turbocharger capacity, at which point boost drops away. That’s preventing the engine revving properly and since there’s no sensor to tell the computer that the trunking is split and leaking, there might not be a fault code issued. Lots of black smoke from the exhaust is often (but not always) another clue that this is what’s happening.