The E40 ECM was the last ECM for the 24X LS, and has does not seem to have universal good reviews. A comparison of the E40 to other 24X ECM's does not seem to have been made on the forum, at least by a search of thread subjects, so her it is.
For full disclosure, I am also trying to decide which ECM to use for my own LS4 swap. I already have an E40 and harness from a 2006 Grand Prix but am having reservations on using it. I am replacing a Northstar that ran on an OBD1-7765 ecm using a RAM chip adaptor and custom Bin for several years and never got to 100% satisfaction with it. I want to avoid this same experience with whatever ecm I use for the LS4, hence this thread. Others can also likey benefit from the same information.
This article and another Youtube are the most informative info I found about the ECM’s but neither helps in basic decision about which to use for a swap and why. What's available or what you already have is not a good enough single reason.
Article:
The Tuning School Differences and Applications of GM ECMsVideo:
PSI How To: Which PCM should I use on my LS / LT SwapE40 ECM:
- used in 2005/6 in relatively few vehicles including Grand Prix, Impala, Rainier, SSR, Trailblazer, Envoy, GTO and Corvette
- many posts and writeups refer to the E40 as peculiar and somewhat un-intuitive
- the E40 was still airflow/VE based, and a Gen3 ecm but was a trial ECM for the next Gen4 ecms to come. One write up I read compared it to being like OBD1.5 when we transitioned from OBD1 to OBD2.
- not all pinouts seem to be the same, I have compared the Vette and Trailblazer pinouts to my Grand Prix harness and neither pinout matches completely.
- very few details about the E40 ecm seem to be public either on internet or in print, especially all pinouts and wiring diagrams, except perhaps subscribing to AllData or similar databases. (A single vehicle short term registration with a database is cheap and not a deal breaker, as long as one knows which vehicle to use as the reference)
- Cruse control is not through the ECM but rather the TCM, so even a manual car must retain the TCM
- not sure about how A/C interfaces with the E40
- a benefit of the E40 is that it is relatively small, and the TCM is even smaller so its not a big deal to still have to keep it.
- the fuel delivery is maxed at 64 lbs per hour, not likely a concern for an average LS4
-flex fuel capable if enabled in the tune? Not sure.
Alternate (older) ECM's
P59 (Blue/green plugs, 2003 to 2007)
-used in a lot more vehicles and plentiful to get
- bigger package, so not so easy to hide away
- engine and trans control in one and mostly DBW
- plentiful amount of pinout, wiring, and tuning support available including a/c, cruise, and flex fuel
- fuel capacity is 254 lbs per hour, not likely a requirement for the average LS4
P01 ( blue/green plugs, 1999-2002)
-used in a lot of vehicles and plentiful to get
- same size as P59
- engine and trans control in one and mostly DBC
- plentiful amount of pinout, wiring, and tuning support available including a/c, cruise
So what ECM to use to use? The P59 seems to be more straight forward to integrate DBW, cruise, A/C and Flex fuel despite it being a larger unit. Is it worth the bother to find all the required info for the E40? Does the E40 do anything that the P59 doesn’t other than take up less space?
Please offer your informed opinions.
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Daviero - 88 N* 5spdGT