hello everyone...

i have an impreza 2008 hatchback 2.0L 4x4 that i converted from 4 speed AT to 5 speed manual.

i solved all the mechanical adaption challenges and the car is driving...

my problem is with the throttle, it doesn't open over 30% (opens 100% and immediately closes 70%) .It is actually stuck in safe mode and accelerates slowly because the AT gearbox is disconnected.

i replaced the ecu with the complete lock set (ecu, body control unit, instrument panel, keys & switch) taken from the same model but with a manual gearbox.

unfortunately it doesn't help and the issue remains the same, the clutch and neutral switches are also missing... my suspicion is the harnesses are different between AT & MT models.

when connecting lunch diagnostic to OBD the trouble code is: P0600 serial communication link...

I would appreciate any advice to solve this problem, thanks!

 

P0600 is a very broad spectrum error code and would need further investigation using Subaru select monitor.





However as you are still using the AT (SportShift) wiring, I would think that the Transmission Control Module (assuming it's still fitted) maybe still influencing the ECU and Body Integrated Unit.

Without the correct wiring loom/s and missing switches the ECU and BIU may not be getting all the correct information it requires - see pdf below.

function setting pdf

 

Don as usual comes up with the goods but you are going to have a nightmare sorting this out you really need the correct loom.

 

Thanks Don...
The TCU is disconnected right now and there is no difference also when it is plugged in.

Can you explain about the loom ?
is the trouble shooting table you sent me referring to trouble code: P0600??

thank you for the PDF files they look very useful...
Do you have any idea about changing the body integrated unit settings from AT to MT gearbox?

 

There appears to be differences between the MT and AT vehicle main bulkhead wiring loom (looking at the part numbers) which is not to be unexpected given the variation in sensors and switches.
Have you bypassed the AT inhibitor switch?
Clutch switch - you haven't added
Neutral position switch for the MT box?

Have you got the wiring diagrams to compare differences between AT and MT ?

What you see is what you get. DTC P0600 page refers you to the LAN section page which is second item.
These are the DTC's for the LAN diagnostics which you may not be able to access unless using SSM or a very expensive code reader with the correct access modules.
MY08 Impreza LAN DTC's pdf
Note the references to P0600 on the second page

All changes in the BIU are done using Subaru's Select Monitor software

Here is the ECU pin out for the NA engine
MY08 N/A Impreza ECU pinout