VW golf mk5 MED9.1 no communication

[madman47]

Hello all as in title MED9.1 no comms with diag tool.
Engine is not running and fans on full.

Someone mentioned maybe a checksum error could cause this?
The HW appears ok.

Any ideas?


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[pablo1971]

check obd connector for power etc...if ok...maybe ecu is faulty...

[al70]

check for water damage around the relays under the dash, goodluck.

[madman47]

Fault is within ecu.
No water ingress.
All hw looks ok inside ecu.
Is it possible checksum can cause no comms?


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[rafal]

Can be 100 reasons.... without good diagnostic we are not able help

[tepSIJA]

Hello all as in title MED9.1 no comms with diag tool.
Engine is not running and fans on full.

Someone mentioned maybe a checksum error could cause this?
The HW appears ok.

Any ideas?


Sent from my iPhone using Tapatalk

in most cases ECU is faulty , but also CS can be reason for your problem like wiring and water in some of conectors.
Try from cheap stuf like, check connector , wiring and if all is ok try with ecu .

did you make some moding on ecu maps or ?

[geeroam]

Have you tried wiring the ecu up on bench and diagnosing?

[rafal]

i am thinking how many posts more will be here...........................
as i said - without good diagnostic - help impossible - or if somebody have magic ball - lol
to find problem - why not comm - by wifi - it is like win in lottery

[al70]

i have a gol5 5 tdi lying in the yard all winter, tried to start recently, fans on full, no swing, this car was perfect before the winter, it was remapped though, but battery went completely dead, i have'nt diagnosed yet but when i lifted the bonnet it was covered with leaves, theres a little coin box below the steering wheel when opened it was full of water, check the relays around the steering column, i once had a rela in an a4 that was so full of water i couldn't even feel or hear the water inside, goodluck

[al70]

:party :hey, we're locked down, why not, lol

[alex_r_2001]

Ive had a couple ecu no communication..... after checking wiring and verifying all is good and making sure the was 5volt reference going to sensors ... I revived them by replacing can transciever ic in them..... if sensors have 5volt rerefence check can pins on ecu if stuck on zero volt or a abnormaly high voltage replace transciever..... 2.2 volt to 2.6 volts.... if you have a pico scope or any good lab scope makes it easier to check but not necessary ...... goodluck