coding plug faulty on instrument cluster

[mystic_525_tds]

my car is a 525tds 1993 and i had eratic guage behaviou so recently i replaced the capacitors on my cluster and it did not work so i bought a 520i cluster for £25 from a breakers.

the rev counter had a different range due to mine being a tds so i swapped the rev counter and the 'diesel' fuel gauge over, fitted the cluster and hey presto it was working and then i realised i had not changed the coding plug as the mileage was at 222k and mine is 156k.

i changed the coding plug to my original one and then the rev counter and temp guage were reading way too high, i then put my 520i coding plug in and the guages were fine again.

so it seems its the coding plug that is actually faulty, i was not aware that this could cause cluster problems, now the coding plug i have has 222k on it also the rev counter reads about 600 higheras at tickover its 1500 rpm so my rev counter is still not right but everything else seems fine.

can anyone advise on this and do i need to buy a new coding plug or can i recode or flash the 520i coding plug to hold the info on my car ie mielage and car details, i read somewhere this will fix the problem with the rev counter reading a bit high.

could the coding plug be flash using carsoft or bmw scanner ?

[NielsGalan]

I had a similar problem after I bought my car. RPM gauge and econometer only worked on and off, mostly off. After a lot of trial and error (LONG story) I found out that is was the coding plug that had a lot of bad solderings.

Inside the coding plug (mine at least) there is a chip attached to a print plate. Several of the solderings between the two were cold, causing the connection to be bad. I had all the legs from the chip re-soldered, and it has been fine since. My car is older and has a different engine, but possibly you have the excact same problem.

Good luck.
Niels

[mystic_525_tds]

I had a similar problem after I bought my car. RPM gauge and econometer only worked on and off, mostly off. After a lot of trial and error (LONG story) I found out that is was the coding plug that had a lot of bad solderings.

Inside the coding plug (mine at least) there is a chip attached to a print plate. Several of the solderings between the two were cold, causing the connection to be bad. I had all the legs from the chip re-soldered, and it has been fine since. My car is older and has a different engine, but possibly you have the excact same problem.

Good luck.
Niels

thanks for the info niels, i will have a look at the coding plug and check the solder.