Alfa Romeo Owners Club of Australia Forum

Technical => 939 Series (159, Brera and Brera Spider) => Topic started by: ragazzo on August 15, 2018, 01:46:15 PM

Title: Voltage Difference
Post by: ragazzo on August 15, 2018, 01:46:15 PM
I have 2008 159 2.2 JTS Selespeed

When I measure voltage on battery terminal and via MES it measures 0.5v lower (cold in the morning)

EDIT: The voltage is actually matching on ECU but 0.5v lower when connected to Selespeed computer

Is this a concerning difference ? or natural ? because I've been having a bunch of electrical problems that I'm trying to resolve. I'm was having below issues


It spent 2 weeks in AR specialist garage for repair & service with no difference afterward so I decided to take it on my hands. The mechanic was blaming ABS module for all these problem but I don't think a single module error can cause such wide range of issues.

I already strengthened all earths under the hood, fitted a brand new battery (85a/800cca), checked alternator, visually checked main CAN lines under the footwell and cleaned all fuseboxes and finally it made few progress.


Other than all those problems the car runs good.

So back to the "Voltage" topic I'm suspecting ECU (maybe) or Body Computer's weakened connection (external/or internal) may cause this lower reading and causes random faults rather than individual sensors or modules doing so. I guess Body Computer is more responsible for those type of problems so just want to find out if the voltage difference between Engine computer and Selespeed computer is really concerning issue or not.