MBE 992/9A4 pin-outs - alternative (numpty) diagram

[Shortshift]

Came across MBE9A4 4Cyl COP-1342.pdf and thought it worth sharing as a diagram to complement the usual pin-out table that is often seen online for use with MBE 992/9A4 ECUs.

I found this chart useful for a number of reasons, including that it helps to show a numpty like me the 'switch to earth' functionality of the ECU for injector and coil firing.  Somehow, this diagram makes it all so much easier to visualise and understand.

A small, additional point that I have commented on elsewhere; the diagram shows that the cam sensor return should be connected to 0V at pin #23 (which is how they are wired, ex factory) and not to pin #31 as has been mentioned previously on Blatchat.

James

[Jonathan Kay]

MBE9A4 4Cyl COP-1342.pdf

[ChrisC]

Just a point, my 2020 and 2016 Duratecs had a permanent 12v supply as well as the ignition switch 12v supply.  I can't be 100% certain but I think that was also the case for my 2011 Sigma.   So it seems there are some inaccuracies in that diagram. 

[Shortshift]

Chris - it's not a Caterham-specific diagram but, as is the case with the more normally published ECU pin-out tables, it depicts a generic MBE 992/9A4 configuration (including, for instance, other features that are not normally found on a Seven, such as power shift, traction control and so on). 

So you may have to overlay your own individual power-supply circuitry (cut-off switch, ignition switch, starter button, etc) but as far as ECU inputs and outputs are concerned it's 100% - and complements the usual pin-out tables perfectly.

James

PS: Are you sure that your ECUs are permanently powered, even when the car is keyed-off?  I'd find that rather surprising; are you sure that 'permanently powered' doesn't mean 'through the ignition switch'?

[aerobod - near CYYC]

Also note pins 16, 17, 19, 25, 27, 33 and 34 are all programmable, so can have any number of different functions assigned to them:

[Ian Macquarie]

#1 A small, additional point that I have commented on elsewhere; the diagram shows that the cam sensor return should be connected to 0V at pin #23 (which is how they are wired, ex factory) and not to pin #31 as has been mentioned previously on Blatchat."

As far as I can see on that diagram MBE 9A4, CAM Inductive signal goes to pin 30 and the 0V goes to pin 5 0V. I can't see a pin 23 or pin 31 on there at all. Is there another diagram I'm not seeing?

[Shortshift]

Replying to #5:

Yup - and as you've mentioned before James (Aerobod), these programmable pins are features of the more recent 9Ax architectures, and are not present on the older 992 spec ECUs.

 

Replying to #6:

Yes - if you cross-refer the diagram I have posted with the pin-out table that James (Aerobod) has reposted (that's the more commonly published chart), you'll see a number of pins which offer 0V, including #5, #23 and #24.

James

 

 

[aerobod - near CYYC]

Re #6 - Pins 5, 23 and 24 are 0V / ECU ground. Caterham uses pin 23 for Cam Return (cam signal ground), as opposed to the MBE provided Cam Return on pin 31.

[Shortshift]

Ref #8:

You mean: Pins 5, 23 and 24, James??

James

[aerobod - near CYYC]

Re #9, yes, finger must have been too far to right on keyboard, will edit.