1998 truck tcc boggle
December 5th, 2019, 11:34 AM
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1998 truck tcc boggle
Hey guys I have a 98 1ton gm truck with the 5.7l and I assume it's the 4l80...around 300,000kms on it. I bought it used with this issue.
Problem is I can drive all day under 60mph and everything is fine...if I do 60 or over for more then a minute or so the tcc unlocks slightly... A few hundred rpm...and will not lock again until I restart truck. If I plug in scanner while driving and clear codes tcc locks in seconds. Only codes that are there are a few o2 sensor and a steering assist...this is using an updated efi live scanner...now I have checked speed sensors... One in tcase had some metal fillings on it I cleaned off but no help. Wires and harnesses look good...
Fresh oil in transmission as well
Any suggestions to besides take it to the dealer?
Thanks, Lyle.
Problem is I can drive all day under 60mph and everything is fine...if I do 60 or over for more then a minute or so the tcc unlocks slightly... A few hundred rpm...and will not lock again until I restart truck. If I plug in scanner while driving and clear codes tcc locks in seconds. Only codes that are there are a few o2 sensor and a steering assist...this is using an updated efi live scanner...now I have checked speed sensors... One in tcase had some metal fillings on it I cleaned off but no help. Wires and harnesses look good...
Fresh oil in transmission as well
Any suggestions to besides take it to the dealer?
Thanks, Lyle.
December 5th, 2019, 1:08 PM
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Does your scanner give you live TCC status?
December 5th, 2019, 1:34 PM
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I'm sure it would if I could sit down with a computer and mess with it. I will hopefully get time for that this weekend.
It is unlocking slightly...ther must something that commands it unlocked...seems like there should be a dtc due to the fact of I reset it locks and will stay locked until I go over that speed again...
It is unlocking slightly...ther must something that commands it unlocked...seems like there should be a dtc due to the fact of I reset it locks and will stay locked until I go over that speed again...
December 10th, 2019, 6:09 PM
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So I got scanner to work...tcc unlocks and slip is 200-600rpm... Tcc mode reads off during this condition...duty cycle I believe was 0%...but I may have had wrong pid..
Input and output speed sensors dead on.
Now just before it does this unlocking limp mode no code business, I notice a miss fire count on the total shoot up...seems to be from cyl #1... All the rest at zero. Change spark plug...now cyl 1 (along with all the others reads zero missing... but the total count still goes up at around that 2200rpm 60-65mph...after Changing plug it seems I can go faster b4 things get weird...so now I think it has something to do with this miss fire...but why no missfire codes? And why it can't detect any misfires on individual cylinders but still gives me total? Gona look into crank sensor tomorrow...maybe put a different coil I got kicking around..
Input and output speed sensors dead on.
Now just before it does this unlocking limp mode no code business, I notice a miss fire count on the total shoot up...seems to be from cyl #1... All the rest at zero. Change spark plug...now cyl 1 (along with all the others reads zero missing... but the total count still goes up at around that 2200rpm 60-65mph...after Changing plug it seems I can go faster b4 things get weird...so now I think it has something to do with this miss fire...but why no missfire codes? And why it can't detect any misfires on individual cylinders but still gives me total? Gona look into crank sensor tomorrow...maybe put a different coil I got kicking around..
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