Blu_Redline said:
And a different ECU is a different ECU. I have been letting an individual hook up to my car's ECU to get info for a product of his and have found out that the 04 ION Red Line has a Saturn specific Motorola unit in it that is different from the ECU in the '05 ION Red Line & Cobalts SS.
I have also had conversations with a tuner garage that is waiting on the software to be finished to re-program the Cobalt SS & 05 Red Line and was told that it was not for the '04 Red Line. It seems that this software company provides software for the C5 corvettes that help out a lot with their engines and the same should be true for the LSJ cars. I then asked a GM dealership service manager about buying an '05 ECU and throwing it into the '04 Red Line and he told me that it just isn't that simple, that our connectors could be different and the sensor parameters could be wired differently for the Motorola unit that would not be compatable with the different unit for the '05s. Sucks
dazednconfused75 said:
That seems to be very bad news.
Don’t sweat it Dazed, this is mostly incorrect information IHMO
Went through all of this a few weeks back while doing some research on the ECM for this thread:
http://www.redlineforums.com/forums/showthread.php?t=1688
The 04 and 05 RedLine ECMs ARE identical, (exact same part number) but there are some wiring differences The wiring differences between the 04 and 05 Redlines are very minor and related to the optional Performance Pack (RPO

DA/UXE) . It remains to be seen if the PP equipped vehicles are going to use a different calibration. (haven’t seen one yet) This will be important if anyone has plans to attempt to add the PP gage pod into an earlier RL.
The differences between the RedLine and the Cobalt ECMs are a bit more significant, but they ARE basically the same ECM (Motorola based PO5), with the exact same connectors and even share the large majority of wiring details. BUT they ARE a different part numbers than the Redlines and appear to maybe have some minor I/O differences, but the extent these differences affect the ECM internal hardware, has yet to be fully established.
The PRIMARY differences I found between the RedLine and SS ECMs were as follows:
1. The RedLine’s ECM is pure Class 2. It is connected to the Class 2 network ONLY, and the Redline does NOT utilize a High Speed GMLan. It’s networking topology is a mix of Class 2 and Low Speed (single wire) GMLan only.
2.The Cobalt DOES use a High Speed GMLan network and the ECM is on BOTH the Class 2 and High Speed GMLan networks. (*it also has a LS GMLan subnet)
Now it is my belief that the Redline ECM actually DOES have the capability to function in a HS GMLan, but as there is no HS GMLan network, these ECM terminals are just not connected. ALL of the other wiring is connected to the exact same terminals as the Redline and even share all of the circuit numbers.
But this networking difference appears to have 1 main significant difference and that’s in the way the cruise control is wired.
The Redlines steering wheel mounted cruise control switches are wired directly to the ECM so it can control the motorized throttle for cruise control operation.
On the Cobalt SS, the cruise control switches appear to be identical, BUT they are wired to the Body Control Module (BCM) and the switch data “shared” along the HS GMLan network to the ECM, which in turn control the throttle motor for cruise operation.
This is the only major difference I found. I also found the Cobalt SS shares the use of a single circuit for the boost pressure gage as the Redline’s Perf Pack BUT since it doesn’t use a “pod” with LED tach indicators, these ECM terminals are listed as “Not Used”
So what does this all really mean? Well 04 and 05 Redline owners can rest easy in that there is very very minor differences between their ECMs. And while yes they DO use different software files, keep in mind this is not unusual for GM to keep the calibration files for each model year totally separate, even when they maybe identical (other than filename). This is just the nature of the beast as the reprogramming software used is VIN based and therefore indexes/references the calibration files by model year FIRST, then platform, then engine RPO then optional RPOs such as tire size and presence of things such as the Perf Pack.
Not sure if this totally clarifies things for those of you interested in this sort of thing but…
Regards
WopOnTour