Flex

[brewguybox]

I'd like to add flex fuel option to my 2004 Sonoma with the 4.3 vortec V6 MPI. Its PCM is the green/blue P59 running OS 12587603. The PCM has the capability of running flex with the composition sensor and DBW even though it is DBC. To my knowledge, none of the s-trucks were available with Flex. My question is: is it as "simple" as adding the input pin from the comp sensor to pin 57 on the PCM and enabling flex option in the fuel tab and copying in the alcohol values into the alcohol EQ table and Blend table? Or, will the engine management parameters not allow composition input because it won't "look" for that input? Thanks in advance for any input.

[brewguybox]

I may be confused about the plug colors because its been a while since I unplugged the PCM to install the e-fan controller harness.

[5FDP]

As far as I know it should be that simple. If it's wired right and the DTC's are enabled for the sensor, it should function.

[brewguybox]

Thanks so much for the info. I?ll give it a try. I saw another thread after I posted this about having to modify the bin file. That is a little more complicated than I?d like to get with the 4.3. Especially since I plan on swapping it to a 5.3 in the nearish future. At that point, I can then just do a full segment swap. Until then, I would like to try to make work on the 4.3 if I could.

[5FDP]

It very well could be possible that it needs an operating system that had it from the factory though. Like a 2004 Tahoe or Suburban OS that had flex fuel from the factory.