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Injector Flow Rates IQA not programming to GPCM

Nathan Owner/Technician Colorado Posted   Latest  
Question
Resolved
Programming
2015 Chevrolet Silverado 2500 HD LTZ 6.6L (8 LML) 6-spd (6L90) — 1GC1KWE83FF597733

All injectors were replaced on this truck. :I select ECM > control functions> and wrote the new flow rates with GDS2 but when I then go and select “Write ECM Injector Flow Rates to GPCM” it says “Completed” but in the data list they remain as asterisks. (See pic)

The truck is tuned. The GPCM shows as active in module list, but I can't read data out of it. I suspect it has been tuned to appear there but not funtion?

Anyways I would just like to confirm that it ok to drive with only the ECM flow rates apparently programmed. 

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Scott Owner/Technician
Michigan
Scott
 

I believe the gpcm only stores the injector flow rates as a backup to the ecm so they can be transferred without recording all of them visually and entering them in manually

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Nathan Owner/Technician
Colorado
Nathan
 

Thank you

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Marvin Mechanic
Mississippi
Marvin
 

The glow plug module stores the codes so if you have to replace pcm you can copy it from the mod to pcm instead of trying to read them from dirty injectors or pulling them to read them .have you tried reconnecting scan tool again like it was first time and see if if the data is there ..in both modules ..not setting and glow plug module codes ..maybe lost power to it while doing other work .we…

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Nathan Owner/Technician
Colorado
Nathan
 

Thank you

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Nathan Owner/Technician
Colorado
Nathan Resolution
 

I had another similar vehicle that I did a PCM replace on since then. When running copy IQA from GPCM to PCM utility, only asterisks showed for both modules but when I clicked on “copy to PCM” they all showed up. I suppose GDS just doesn't like to display the GPCM codes but it does indeed store them. Confirmed fix.

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Resolution Ð Awarded
National Institute for Automotive Service Excellence. Working to improve the quality of vehicle repair and service by testing and certifying automotive professionals. Corporate Partner