Part number Model Year Bosch number Remarks/changes Questions
928.618.123.00 928 S2

'84 - '86

0 280 002 501 Bosch LH2.2 version no temp sensor failure program
928.618.123.02 928 S2

'85 - '86

0 280 002 502 Bosch LH2.2 version temp sensor failure program
928.618.123.04 928 S3 '85 - '86 0 280 002 503 Bosch LH2.2 version used in S3 models
928.618.123.10 928 S4 '87 0 280 002 504 early model for the '87 Non-DIA. Bosch LH2.3 version already.
928.618.123.11  928 S4 '88 0 280 002 504 3 pos fault memory, 5 starts reset Bosch LH2.3 DIA noted on the label
928.618.123.12 928 Club Sport '88 0 280 002 506 Different specs for the sportier CS type: different cam timing, rev limiter from 6600 to 6775 rpm map i.e. EPROM only? Different EZK too!
928.618.123.13 928 S4 '89 - '90 0 280 002 507 Has extended fault memory (11, 50 starts reset), added ignition monitor circuit with thermo elements in 2 exhaust ports. LH can detect activation of the Ignition Monitoring Relay (IMR). automatic S4? What is so special about the automatic version? Reduced RPM when it gear? Is that it? The Idle controller remains operational when the ecu is in diag mode.
928.618.123.14 928 GT '89 - '90 0 280 002 506 Digital dash and has fault memory, added ignition monitor circuit with thermo elements in the exhaust ports. LH can detect the IMR relay activation manual s4/gt ? Possibly different due to 6800 rpm cutoff where the s4 has 6600
928.618.123.25 928 S4 automatic '91 0 280 002 509 Addition of the 'check engine' lamp feature in Canada and US models. It triggers the dash lamp when emission control malfunctions happen. California Legislation !  
928.618.123.26 928 GT manual '91 0 280 002 508 Addition of the 'check engine' lamp feature in Canada and US models. It triggers the dash lamp when emission control malfunctions happen. California Legislation !  
928.618.123.30 928 GTS '92 - '94 0 280 002 514 Different fuel map for GTS. What's different in this one compared to the .25/.26 models? Why is there only one model?


I am running the .14 in my automatic S4. I have not tested the "high
side" (135 mph+) limit. No adverse effects noticed. Maybe some
additional mid range grunt, but I'm seldom WOT.
Joe Rausa '89S4


> So what are the differences in the computer and how do I tell if the cams
> and heads are from a GT??

I have a GT brain in my '88 S4, and the only difference I notice is that it
idles ~100 rpm higher than with the S4 brain.



Well, all the LH 928's have LH 2.4.1, so LH2.4 in the late '80s SAABs
would be a little older version, whereas the LH 2.4.2 of the early '90s
SAABs would be a little newer. Basically the only two major things
stopping you from plugging a LH 2.4.2 box into a 928 are 1) the SAAB
4-cylinder brain has only one phase for firing 4 cylinders while the 928
has two phases (twice as many injectors would fry the injectors-firing
transistor instantly on start), and 2) the 3D map would be different
(although the 928 would probably still be driveable).

2) could even be rectified by taking a binary image of the 928 EEPROM and
burning it into the SAAB one.

'86 928S 5-spd w/LSD


Guys - I have done a lot of research on this and in general swapping
Porsche ECU's makes very little difference. The best performance
improvement can be had by swapping the EZK unit to the 1988 Clubsport
unit. This seems to make S4's & GT's run more responsively and
aggressively. I'm currently looking to clone the Eprom from one of
these so I can supply to anyone interested.



Car runs perfect for the first 30 seconds when cold then stalls
Every time after that the car wont hold a steady idle
Plugs have less than 5000km on them
Leads, coils, distributor caps, rotor arms all new last year
No sign of head gasket leaking
Fuel pump ok
All relays and fuses ok
Fuel pressure on rail ok
All injectors ok
LH ECU ran for 15 mins at a steady idle in another 928
EZK ran for 15 mins in another 928
Temp2 sensor ok
Idle stabilizer ok
Throttle position switch ok
Full load switch ok
Flappy ok
No sign of a vac leak (even had air intake off twice this weekend)
No errors on a Bosch hammer test
MAF tests ok (swapped it anyway without success)
Engine wont even start if I disconnect the MAF

Swapped the .26 ECU in the '91 GT by a .30 ECU from a GTS.

I have swapped back to my old one and it wont idle so I have gone back to
the GTS one and it is ok. I have swapped 3 times now and the GTS one works
every time and mine doesn't. Weird shit I know!!!