Motronic MP3.1 diagnostics

[brian j 31]

Hi.

 

my 205 has MP3.1 fitted with the ecu from a zx 1.9 volcane and the loom from a 405 Sri.

in addition I have swapped the mixture pot for a lambda.

apart from needing mapped for my engine spec, it ran well before I sold the car, but now it has been recommissioned, I am getting an EML kit most of the time. While the eml is lit the car is hesitant on the throttle and idles lower, but drives tolerably and passed emissions cleanly. 
I have tried a couple of scan tools on the two pin interface with no luck.

My icarsoft scanner connects to the ECU but shows no faults stored. 

my Lexia refuses to see it is connected to an ecu:

 

has anyone successfully got fault codes out of an MP3.1 setup? If so, how please? 
I am assuming I have either got a flaky sensor or sensor wiring issue but I don’t want to have to fire the parts cannon at it to try and troubleshoot it. 

[DamirGTI 323]

If you do not have "K" light connected , need to make simple DIY diagnostic tool .

 

If it's connected to the cluster ie. the K light , proceed as you would for Motronic 1.3/4.1 ... earth one pin on the green connector and switch ignition ON , and count K light flashes .

 

How to make DIY diagnostic tool , and diagnostic procedure as follows :

All_XM_ECU_Error_Codes.pdf

[brian j 31]

Thanks so much. I will go and try that. 
 

I assume one pin is an earth to it won’t matter if I earth the wrong pin?

[brian j 31]

Worked out which pin was pin 2. 
interesting and unhelpful result though. 
start engine:

eml on

connect pin 2 to ground for 4 secs:

code 1 2 - great. Start code

ground it again for 4 secs

code 1 1 - end. 
no other codes shown. 
for now I have cleared it by grounding pin2 for 15 secs and the eml is now going off when the engine is started.

 

 

[DamirGTI 323]

... or you might've erased it while trying with other diagnostic tools .

 

Drive i for a while and see what happens ...

 

One thing which these old Bosch engine management's do not like is - wrong O2 sensor type !

Must be titania , not the more common zirconia O2 sensor .. as the ECU feeds voltage (5v) to the O2 sensor and looks for voltage drop via O2 sensor for mixture correction .

 

D

[brian j 31]

I drove it around and have codes back. 
 

5 5 and 2 1

 

2 1 makes sense. The throttle pot was a cheap, nasty POS when I bought it 8 years ago, but all I could get in a bind.  I have a new one ordered.

 

the lambda is the correct part (genuine Peugeot) albeit old now.  It may be faulty but it isn’t the wrong one because it hasn’t been changed and was fine for a long time after fitting. 
 

5 5 does not appear in the list of codes. It is definitely 5 5 and not 5 4 (phew).

 

any ideas what that could be?

 

 

 

[brian j 31]

1 minute ago, brian j said:

I drove it around and have codes back. 
 

5 5 and 2 1

 

2 1 makes sense. The throttle pot was a cheap, nasty POS when I bought it 8 years ago, but all I could get in a bind.  I have a new one ordered.

 

the lambda is the correct part (genuine Peugeot) albeit old now.  It may be faulty but it isn’t the wrong one because it hasn’t been changed and was fine for a long time after fitting. 
 

5 5 does not appear in the list of codes. It is definitely 5 5 and not 5 4 (phew).

 

any ideas what that could be?

 

 

 

Just found my own post from 2012. It had a 5 5 code back then which we decided was CO pot related (it is missing now the car has lambda, so makes sense)

amazing what you forget in 12 years. 

[brian j 31]

Looks like I am not going to be so lucky.  A new Delphi throttle POT has been fitted and it is still throwing an intermittent 21 code. 
looks like I have to delve into the wiring. I assume there is either a corroded section somewhere or maybe even some rodent damage from storage. Deep joy. 

[brian j 31]

One corroded connector replaced. All is well with the world. Yay!!! 
thx all for the help. 

[pug_ham 240 3 Cars]

33 minutes ago, brian j said:

One corroded connector replaced. All is well with the world. Yay!!! 

Which connector was corroded @brian j?

 

Just for if someone else has the same problem out of the few of us also running mp3.1?

 

g

[brian j 31]

11 hours ago, pug_ham said:

Which connector was corroded @brian j?

 

Just for if someone else has the same problem out of the few of us also running mp3.1?

 

g

Hi Graham, sorry I should have said, but I’m afraid it won’t be much of a help to others. 
when I first fitted MP3.1 back in 2012 my TPS didn’t work as expected. You helped me out with a wiring diagram and I needed to swap two pins in the TPS plug. I put an extra, reversible connector in the loom to allow me to swap and if ever needed swap back without having to de-pin the JPT connector. My additional connector corroded. 
Probably not of use to anyone else, but helpful to me because it was an easy find and fix.

Pls can I just give a shout out. There are a few on here who have been consistently helpful and knowledgeable for both durations of me owning and modding this car over a 15 year period. Not many places where that would happen!  Proper, proper thanks to you all.

[pug_ham 240 3 Cars]

Ahh, OK.

 

 

It's odd that the TPS on MP3.1 seems to have a different pin out to  other TPS's used on ecu's like the MM8P etc.

 

I had to do the same on my car when I first got it up & running but we swapped the pins around in the original plug.

 

g

 

[SRDT 146]

The XU10J2TE and XU10J4 also have two TPS pins to swap and they are both using MP3.2 with a similar TB design.