2002 A160 f fault code po758 HELP PLS!

[montz230e]

hi guys my partners a160 2002 100k miles has developed the dredded f fault with auto box
i pluged it in and it gave the code po758 which is shift soleniod b fault
looked causes up which said ,, low oil level ,, dirty oil ,, solenoid faulty ,, solenoid harness and po758 comes up when ecm detects its in wrong gear that tcm sellected or something!!!
can anyone help me in what to do to fix this myself am mustard with spanners sockets but need directing on what to eradicate and in what order
thanks

a very merry christmas to you all

 

[wongl]

When was the last time (mileage wise) was the gear oil and filter changed?

 

[montz230e]

hi
oil was changed using recomended oil from mercedes 8k ago and about 2 years
this is why i wasnt thinking it was the oil

 

[montz230e]

anyone!??

 

[forrera]

fault code p0758 is not the code you're looking for. you should get other fault codes too.
the better the scanner the more codes you get.

 

[ChrisA]

OBD II Fault Code

OBD II P0758
Fault Code Definition

Shift Solenoid B Electrical
What does this mean?
The purpose of the automatic transmission is to match the engine's optimum power and torque characteristics to the driver's desired rate of acceleration and speed by auto-selecting different gear ratios or 'speeds' to power the wheels. Shift solenoid B enables the transmission to shift from 2nd gear to 3rd gear. It does this by re-directing the flow of the transmission fluid which changes the position of the shift valves in the valve body.
When the code P0758 is set in the Powertrain Computer, it means that the Powertrain Computer or PCM is not seeing the specified rpm change that occurs during a shift from 2nd gear to 3rd gear. It's also not seeing the correct increase in road speed from the vehicle speed sensor.

Symptoms

Check Engine Light will illuminate
Vehicle will not shift from 2nd gear to 3rd gear properly
Decrease in fuel economy
In unusual cases, there are no adverse conditions noticed by the driver
In some cases, there may be performance problems and possibly misfire-like symptoms


Common Problems That Trigger the P0758 Code

Defective Shift Solenoid
Defective Shift Solenoid wiring or connector
Defective Valve Body
Dirty transmission fluid that restricts the hydraulic passages

 

[ChrisA]

Check that the Transmission fluid is of a Cranberry type colour and not a Brown or burnt colour

 

[forrera]

look at this ebay listing

Mercedes A class W168 Automatic Gearbox Diagnostic Repair Service | eBay

 

[montz230e]

hi, took oil out today and it is quite a brown colour also looked at filter which is a bit dirty .would this really bring up f fault and stop it shifting ?

 

[wongl]

Since you have drained the gearbox and removed the filter you might as well replace it with a new filter and fresh oil to seem if the fault goes away.

I would suggest buying the AFT oil and new filter from Mercedes Benz directly and avoid aftermarket products.

 

[montz230e]

yes i do agree but being honest am bit skint at the mo and didnt really wana spend £100 on oil n filter is this isnt likely to be the cause just to see if it is the fault can i use cheap **** atf ? will it still work with it