I have two cab and chassis trucks that have been previously tuned and now the rear tanks won't work. From what I read its because its the wrong OS from the box tuner they were tuned with.

The OS is currently 12628594 on both but I can't find what it should be.

VIN# 1GBJK39608E186942

VIN# 1GBJK89679E118510

Any Help greatly appreciated..