AEM Pinouts

**Tigchamp** · 01-03-2012, 01:12 PM

I am just going through all the pin conections that I need to do, to conect my 8 channel CDI, COP's & 2 EGT guages/sensors
I also need to conect My AEM Water Injection Monitor, all to a AEM series 2.
The WI Monitor needs a Ground (low side) output to pull timing or boost incase of a fault.
The series 2 AEM has 6 Low side drivers, can I use any of these and then asign the output in AEM Tuner.
Jeff

**Intropy** · 01-03-2012, 05:28 PM

If your WIM provides a low-side output ("switched ground", "pull-to-ground", etc) then you connect it to one of the EMS's spare switched input pins. Then you assign the option you want to that switch. E.g., you might assign Boost Switch Input to Switch 6 Gnd=On and hook it to pin 114. (Just going by your picture, no idea if that documentation is actually correct).

Further confusing the issue is that yes, with the Series 2 you can also use the low-side outputs as switched inputs. Only use ground switches, never connect 12v to your LS drivers! If you need to use a 12v / high-side signal to activate a LS pin, use a relay.

**Tigchamp** · 01-03-2012, 05:43 PM

So You are saying, Firstly use a switched input on the EMS.
But that I can also use a spare ground output.
Thanks, Jeff

**Intropy** · 01-03-2012, 06:00 PM

Originally Posted by Tigchamp

So You are saying, Firstly use a switched input on the EMS.
But that I can also use a spare ground output.
Thanks, Jeff

Right, use a switched input. That's their sole purpose. You can also use a LS driver, but there's no reason to do so unless you run out of inputs.

**Tigchamp** · 01-03-2012, 06:10 PM

Many thanks,
I dont know if you have read my build thread (in the sig) but I have two fans mounted on my SMIC's can I use the same method and have them switched on at a given AIT?
Jeff

**Intropy** · 01-03-2012, 06:53 PM

Not exactly. First, this is an output function, so in this case you want to use an LS driver that grounds a relay for your SMIC fans.

It's not quite that easy though. At the risk of getting too in-depth: the AEM has some limitations, one of which is that you can't just arbitrarily assign conditions to output drivers. For "general purpose" outputs, you're stuck with the parameters they provide, which are RPM, Load, TPS, Road Speed, and Coolant Temp. So you can say things like, "Activate this pin when RPM > 6000 and Load > 10", but not "Activate when AIT > 150".

For your purposes that's probably fine, since high AITs are pretty much going to directly correspond with high load, RPM, and/or coolant temp.

**mb3000** · 01-03-2012, 11:45 PM

Quick question, sorry about the thread hijack.

On the S2 installed on a 1g I was unable to find a high side output to run my fans off of, using this guide:
EMS to Control Electric Fans with High Side Output and Relay

Although that was written for the original ems, I had assumed it was good. Would it be possible to use a spare low side driver with same relay shown in the write up?

**Intropy** · 01-04-2012, 01:21 AM

Of course, that's how you should do it. LS driver pulling to ground to activate your fan relay. The series 2 operates the radiator fans plug-and-play, right out of the box, using the stock wiring though. Any particular reason you're changing it up?

**mb3000** · 01-04-2012, 01:28 AM

Originally Posted by Intropy

Of course, that's how you should do it. LS driver pulling to ground to activate your fan relay. The series 2 operates the radiator fans plug-and-play, right out of the box, using the stock wiring though. Any particular reason you're changing it up?

First generation main fan isn't controlled by the ECU, and as a result isn't controlled by the S2.