My year 2000 pajero 3.2 Diesel (non-common rail) has the following issues:
1. Engine Control Relay: There is No Chech Engine Light, resulting in no start condition. ECU fails to ground the Engine Control Relay. Therefore, in order to start the car, direct ground is applied to the relay.
2. When it does start using the bypass method, it doesn't idle at 750 rpm. Instead, it idles at 1200 rpm or just above that in cold start condition. But as the engine warms up, it starts and idle at around 800 to 900 rpm. The lowest would be 750 rpm.
When it does idle normally, and when I press the accelerator pedal to try to rev up the engine, it revs up ok but on its way back down, it gets stuck at about 1200 rpm and only resets almost all the time upon engine restart.
3. Vaccume solenoids also don't seem to have ground supply, causing the butterfly to stay open even when warmed up or hot. Almost all four vaccume solenoids aren't functioning.
4. When driving around using the bypass method, after driving for 10 minutes or so, the engine revs up high on its own, almost like a runnaway diesel. Shuts down ok with key, but immediate starts result in the same high reving. But after resting for 15 to 20 minutes or so, it starts and idles ok again. This symptom repeats almost all the time.
5. Upon scanning with my Autel mk808k-bt, three MFI codes were detected. Codes 31, 52, and 51 are present.
I've done almost everything and still have not figured this out. Please help.
Hi Rexy.Rexy wrote: ↑Thu Mar 19, 2026 12:03 pm My year 2000 pajero 3.2 Diesel (non-common rail) has the following issues:
1. Engine Control Relay: There is No Chech Engine Light, resulting in no start condition. ECU fails to ground the Engine Control Relay. Therefore, in order to start the car, direct ground is applied to the relay.
2. When it does start using the bypass method, it doesn't idle at 750 rpm. Instead, it idles at 1200 rpm or just above that in cold start condition. But as the engine warms up, it starts and idle at around 800 to 900 rpm. The lowest would be 750 rpm.
When it does idle normally, and when I press the accelerator pedal to try to rev up the engine, it revs up ok but on its way back down, it gets stuck at about 1200 rpm and only resets almost all the time upon engine restart.
3. Vaccume solenoids also don't seem to have ground supply, causing the butterfly to stay open even when warmed up or hot. Almost all four vaccume solenoids aren't functioning.
4. When driving around using the bypass method, after driving for 10 minutes or so, the engine revs up high on its own, almost like a runnaway diesel. Shuts down ok with key, but immediate starts result in the same high reving. But after resting for 15 to 20 minutes or so, it starts and idles ok again. This symptom repeats almost all the time.
5. Upon scanning with my Autel mk808k-bt, three MFI codes were detected. Codes 31, 52, and 51 are present.
I've done almost everything and still have not figured this out. Please help.
This sounds like a very complex problem to resolve.
This site has a wealth of info on it, maybe if you have not done so, do a search?
What i can do in the meantime is copy this across to the WhatsApp group as well as the FB groups which are much more active, but doe not dig deep into this sort of problem. Lets see what happens?
Cheers
Code 31, is the canbus system, which is giving a ground fault, now since we have related issues with the selenoids and boost selenoid I would suggest he start by chasing wires for a faulty ground,
His next step would be to address some vacuum lines and chase wires for those grounds as well. Seeing as the engine idle is all over the place, this is related to the sensor at the throttle body giving bad signals, once again, a bad ground will give this issue.
His best option is to check the top engine harness and also the computer harness grounding wires.
He needs to sort the no start issue first, there is a 99% chance this fixes all related symptoms, the problem is how long diagnosing takes to do properly
His next step would be to address some vacuum lines and chase wires for those grounds as well. Seeing as the engine idle is all over the place, this is related to the sensor at the throttle body giving bad signals, once again, a bad ground will give this issue.
His best option is to check the top engine harness and also the computer harness grounding wires.
He needs to sort the no start issue first, there is a 99% chance this fixes all related symptoms, the problem is how long diagnosing takes to do properly
Thank you for your reply.
I've done a fair bit of wire tracing and testing but I still have not found anything wrong.
I've done voltage tests, Continuity tests, resistance testing etc, from the ECU connectors out to the engine harness, specifically the MFI relay, Vaccume solenoids and Injector pump wirings. I've also done the same towards the ignition barrel, Immo and antenna ring. Everything seems to be ok.
Have I not done everything? I'm just dumb founded.
Interestingly, I've managed to get two different ECU's all belonging to the Pajero 3.2 models but from different years.
My one is an MK369374. I first replaced it with the closest match, a year 2002 ECU I believe, with part number MK386856. This does start the car as well using the bypass method, however, this also does not seem trigger the Check Engine Light.
However, with the year 2005 model ECU (MK386857) I bought online from Mitsu Bitz, it does switch on the CEL, but will not start due to MFI code 54, Immo/key/ECU mismatch related.
I understand they run a different Immo system and chip ID. But any idea how I might be able to make this work?
I've done a fair bit of wire tracing and testing but I still have not found anything wrong.
I've done voltage tests, Continuity tests, resistance testing etc, from the ECU connectors out to the engine harness, specifically the MFI relay, Vaccume solenoids and Injector pump wirings. I've also done the same towards the ignition barrel, Immo and antenna ring. Everything seems to be ok.
Have I not done everything? I'm just dumb founded.
Interestingly, I've managed to get two different ECU's all belonging to the Pajero 3.2 models but from different years.
My one is an MK369374. I first replaced it with the closest match, a year 2002 ECU I believe, with part number MK386856. This does start the car as well using the bypass method, however, this also does not seem trigger the Check Engine Light.
However, with the year 2005 model ECU (MK386857) I bought online from Mitsu Bitz, it does switch on the CEL, but will not start due to MFI code 54, Immo/key/ECU mismatch related.
I understand they run a different Immo system and chip ID. But any idea how I might be able to make this work?