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</TD></TR></T></TABLE>I recently installed Hypertech to my lly o4 duramax. Before I installed it I had 3 DTC codes. Can anybody tell me what they mean. The Codes are: P0670, P0675 and P1626. Before I installed the Hypertech I had removed the muffler and installed a straight pipe, however the Cat converter is still in place. The only other modifications were i replaced the 245 tires with 285 mud grips and I replaced the factory stereo with a Calrion aftermarket unit. Since the install of the hypertech I have noticed a lot more power "set to stage 2", however when the transmission changes gears there seams to be a pause and the a surge. Is this normal. Thanks for the reply's

According to my '01 book, the 1626 is "theft deterrent", so maybe you disturbed something installing the radio? The other two don't show, so I'm thinking they might be egr related. DmaxAllitech?

DTC P0670 - Glow Plug Module Control Circuit.



DTC P0675 - Glow Plug 5 Control Circuit

Interesting. It looks like they added individual control circuits with monitoring in later years? '01 just shows a single P0380 Federal/Cal Glow Plug Controller error. Or does the book just not show the P0670 and 1-8 codes? Anybody know? Baimpala- are you looking in the standard manual, engine controls section?Edited by: jonb