Counter to popular narrative on E30 forums (based on self perpetuating hearsay), there are variant code differences between manual and auto E30 ECU’s and M1.3 didn’t always post date M1.1 ECU’s.

The bad news is that no tuner has a fully disassembled dump of the ECU source code. Most just take the post compiled HEX output and change known sections of code (to gain performance by changing maps and ignition timing).

The short answer is that generally M20 E30’s seem to run fine with Auto or Manual ECU’s swapped between them, but we have no way of knowing if there are subtle differences short of Bosch or BMW providing the full decompiled source code.

Most critically, when buying ECU’s from overseas its important to keep note that variant codes also dictate the presence of an O2 sensor and so swapping in an ECU with an incorrect variant can and will disable O2 sensor data processing.

C01E = Catalytic converter + manual transmission
C05E = Catalytic converter + manual transmission
C29A = Catalytic converter + automatic transmission (without EH)
C25E = Catalytic converter + automatic transmission (without EH)
C35E = Catalytic converter + EH automatic transmission
A05E = Catalytic-converter-ready + manual transmission
A25E = Catalytic-converter-ready + automatic transmission (without EH)
A35E = Catalytic-converter-ready + EH automatic transmission
C21E = Catalytic converter + automatic transmission (without EH)
F01E = Catalytic-converter-ready + manual transmission
F21E = Catalytic-converter-ready + automatic transmission (without EH)
C03E = Catalytic converter + manual transmission + all-wheel drive
C23E = Catalytic converter + all-wheel drive + automatic transmission (without EH)
C33E = Catalytic converter + all-wheel drive + EH automatic transmission
A03E = Catalytic-converter-ready + all-wheel drive + manual transmission
A23E = Catalytic-converter-ready + all-wheel drive + automatic transmission (without EH)
A33E = Catalytic-converter-ready + all-wheel drive + EH automatic transmission
C29E = Catalytic converter + automatic transmission (without EH)
801E = Catalytic converter + manual transmission (318is M42)
B01E = Catalytic-converter-ready + manual transmission (318is M42)
D01E = Catalytic converter + manual transmission (Austria)
D21E = Catalytic converter + automatic transmission without EH (Austria)
D31E = Catalytic converter + EH automatic transmission (Austria)
C81E = Catalytic converter + manual transmission (Switzerland)
CA1E = Catalytic converter + automatic transmission without EH (Switzerland)
CB1E = Catalytic converter + EH automatic transmission (Switzerland)
CC5E = Catalytic converter + manual transmission (Japan)
CE5E = Catalytic converter + automatic transmission without EH (Japan)
CF5E = Catalytic converter + EH automatic transmission (Japan)
C85E = Catalytic converter + manual transmission (USA)
CA5E = Catalytic converter + automatic transmission without EH (USA)
CB5E = Catalytic converter + EH automatic transmission (USA)
C83E = Catalytic converter + all-wheel drive + manual transmission (USA)
CA3E = Catalytic converter + all-wheel drive + automatic transmission without EH (USA)
CB3E = Catalytic converter + all-wheel drive + EH automatic transmission (USA)

This entry was posted on May 22, 2024 at 6:12 pm and is filed under Interesting Stuff. You can follow any responses to this entry through the RSS 2.0 feed.