Tracking down the fault
Another unlucky Mitsubishi Dingo, 4G15 GDI engine, model year 2001. “No power, won’t pull,” said the owner. This particular car had made the mistake of throwing trouble codes — and if the owner had known what “code peddlers” do for a living, he would never have let it happen. The codes themselves are clear enough: P0190 and P1200.
If the car starts and runs, which one do you go after first? The complaint only shows up while driving. So why dive straight into the injector driver module (the DTC P1200 territory)?
Granted — there can be nuances, and the fault could in principle live in the driver module. If a capacitor has come loose, for instance, and a connection makes and breaks while the car is moving, that’s plausible. But if the injector driver were truly dead, the engine simply wouldn’t start at all — and you need that baseline understanding before you start unsoldering things. In this case, however, the driver module had clearly been worked over hard: things had been desoldered, “checked”, soldered back — and very obviously with a 70-watt iron from the hardware store down the road.
Let’s look at fuel pressure instead.
The engine is running at idle. The scan tool is displaying engine speed, ignition advance and fuel pressure, with min/max values logged. Nobody is touching anything, the engine isn’t being provoked — RPM is essentially steady. And even in this perfectly undisturbed state, two things stand out: fuel pressure is low, and — more importantly — it’s not stable. It’s jumping around.
Here’s what the picture looks like when you give it a gentle press of the throttle, in neutral, no load:
And now we lean on the pedal a bit harder and take RPM up to 3,500. This is what the scanner shows:
And there it is. The rest is just the easy bit — replacing the worn-out part of the fuel delivery system that can no longer hold pressure under load. What the previous “technicians” were trying to find inside the injector driver, on the other hand, will have to remain a mystery.
How MotorData Auto-Electrics would have helped
Start with DTC P0190
The software doesn’t just point at the lazy answer — “swap the fuel rail pressure sensor and see what happens.” It also tells you to verify the fuel supply line up to the high-pressure pump. Which, in this Dingo, turned out to be exactly where the problem lived.
Now the second code — P1200
For P1200, the same logic applies — instead of pulling the injector driver apart, you check the “injector circuit open” feedback signal, which is the return signal coming back from the driver module itself.
To chase a fault like this one all the way down, the technician needs a working knowledge of how the GDI fuel delivery system is built and how its control strategy operates.
Alexander V. Markin © Legion-Autodata (forum handle on Legion-Autodata: A_V_M) Belgorod, Tavrovo mcr. 2, Parkovy ln., 29-b Union of Automotive Diagnosticians
