Problems with connecting ECU on my 2004 MGTF 135, LHD. Communication failure.

Coming home after a trip of 3000 km from Norway to UK and back, I ordered and changed the spark plugs, air filter and coils as well as the car-battery. All well for a short (50 kms) testride. Next day the engine didn't fire at all. The fob worked well and opened the centrallocking and cut off the alarm. I tried to read Faultcodes with my Biltema ECU-reader, but it didn't get in touch with the ECU. In my knowledge, the engine need both petrol and spark to fire. As it didn't smell petrol in the garage when turning the engine over much longer than normal, my thought was the fuel pump. I made a by-pass over the power side of the fuel pump relay, and heard the the feul pump started. From the electrisc diagram, I noticed the control current side of the relay is in contact with the ECU one or other way. So I bought a new Pscan and got it two days ago. Installed the SW on my PC (not without some troubles with the Windows defender...), and connected it to the car. It communicated with the SCU, but again no communication with the ECU. It failed communication trying to connect both fast and slow init. I thought it might be my installation of the SW, so I connected the pscan  to my other TF (also a 2004, but 160). It communicated well with the SCU and also with the ECU reading faultcocodes etc. So the pscan worked, but could not get in contact with and communicate with the ECU on my other TF 135. Have anybody out there experienced similar? Could it possible be the ECU unit itself failing, or the wiring from the OBD2-contact to the ECU? Is it a straight forward job to swithch the ECU? Sorry for my bad English writing, as Norwegian is my mother-language.

G'day and welcome to The-T-Bar you question is probably better asked in the section dedicated to Pscan questions I'll move it for you.
In the mean time may I suggest you have a look at our checklist for new members and owners:  https://www.the-t-bar.com/forum/54-how-tos/99326-a-check-list-for-new-owners  
It wont answer you current question, but will give you some useful pointers.

Thanks for answering!. I have followed tge T-Bar Forum for some years (have had TF since 2011). I have read many topics about the Pscan, and finally bought one. As for myself, I have two TF's: Both 2004 80th Anniversary - one Goodwood Green 135 hp and the other Starlight Silver 160hp (currently not registered, awating some minor repairs). Hpefully someone have an answer for me, as there is not so much knowledge on TF's here in Norway as in UK!

There is no straight answer in such situations.  I would elimimate wiring from OBD port to ECU by measuring continuity. If I am not mistken you already have electric diagram so will know which pin on OBD and ECU side needs to be measured. 

Also look at the connectors on ECU and on wiring side for the engine ECU to see that all pins are correct and straight and not bent or similar.

Also check wires at boot hinge, since earthing point of engine ECU is there, so you might have earthing problem affecting engine ECU.

check that there is power and earth to the engine ECU.  Maybe the fuse has blown?

Lack of power to the ECU could be the reason why the engine died as well as the reason why it won't communicate with pscan

also, as you have two cars both with MEMS3 you can try swapping the ECUs

The engine won't start, but you can see if the diagnostic protocol starts to work

Hi and thanks for your answer, Roverlike.
I have downloaded the Electrical Circuit Diagram (59 pages, unfortunately only RHD), but where do I find which pin on OBD and ECU side that matches and shall be measured for continuity? The diagnostic socket (OBD) shown on page 12 and page 22 shows pink cabling between them - C0040-7 on socket via a common connection point SJ38 to C0159-58 on the ECU (ECU=ECM?), but not indicating which pins that is connected (if I understand the diagrams correct) on each side. Could you please explain for me where I can find that?

Thanks for answer from Pscan.
Can I switch the ECU between the cars without making something go wrong? The cars are both 2004 80th Anniversary, but with some different equipment; The 135 with AC and ABS (imported from Germany (VIN 631872) and the 160 without AC (VIN628049) (sold new in Norway as 1 of 8  80th Ann sold in 2004), but with ABS. Both have Pektron and MEMS3. I'll first chech the earthing and that the ECU have power. The 135 is so called a Mk2 and the 160 is a Mk1.

Askerper wrote:

Hi and thanks for your answer, Roverlike.
I have downloaded the Electrical Circuit Diagram (59 pages, unfortunately only RHD), but where do I find which pin on OBD and ECU side that matches and shall be measured for continuity? The diagnostic socket (OBD) shown on page 12 and page 22 shows pink cabling between them - C0040-7 on socket via a common connection point SJ38 to C0159-58 on the ECU (ECU=ECM?), but not indicating which pins that is connected (if I understand the diagrams correct) on each side. Could you please explain for me where I can find that?

OBD connector is C0040 and pin on that connector is number 7. That is what C0040-7 menas.
Same thing for the ecu side. ECU connector is C0159 andmpin is number 58.

 

 

Askerper wrote:

Thanks for answer from Pscan.
Can I switch the ECU between the cars without making something go wrong? The cars are both 2004 80th Anniversary, but with some different equipment; The 135 with AC and ABS (imported from Germany (VIN 631872) and the 160 without AC (VIN628049) (sold new in Norway as 1 of 8  80th Ann sold in 2004), but with ABS. Both have Pektron and MEMS3. I'll first chech the earthing and that the ECU have power. The 135 is so called a Mk2 and the 160 is a Mk1.

In my opinion it won't do any harm, but I can't be liable if I'm wrong. You need to do your own due diligence by inspection of wiring diagrams etc to see if the differences are significant.

I fitted a Rover 75 ECU in a Freelander 1 and nothing bad happened.

If it was me, I would just swap them and try the diagnostics. As I said, the engine won't start with a swapped ECU, but the diagnostic protocol should work.