2007 Silverado Vortec Max. 6.0, 4WD, LTZ.
Over the last couple of months, the StabiliTrak and Traction control systems arbitrarily turn off by themselves. This has happened 6-8 times. The display doesn't say to service the systems, it just says they are off and the warning lights on the dash light up. The speedometer continues to work. The ABS lights stay off.
When this happens the transmission starts shifting at what seems like full line pressure. Like bark the tires shifts into second. This can last anywhere from 100 feet to 10 miles. Then the lights go off and everything is back to normal.
Cycling ignition power changes nothing. Cycling the traction control switch does nothing.
I am assuming one of any number of sensors is failing or possibly a module. However I would think a service system message would appear if that was the case. Does this system record faults and would a shop be able to read them? I don't want to take it to a shop and have them just shoot a parts cannon at it.
As an add, another odd fault happened a couple of weeks ago. I had to jump start the truck on a Monday morning after sitting for 4 days. I had left all the electronics on. It jumped with no issue but the tach was reading 5500 rpm at idle. It behaved normally other than idle at 5500. If you revved the engine, the tach would increase from 5500 past the end of the gauge. I disconnected the battery for a couple of hours and it returned to normal.
Thoughts? Or take it to the dealer and let them sort it out.
My first thought is bad ground(s), but you aren't in the rust belt, so maybe not.
Edit: are the battery cables okay? Any excessive corrosion?
Maybe low voltage as well. Saab's would do all kinds of weird stuff as the battery would degrade. Try swapping it and see what happens.
Check the battery. This is stuff a weak battery causes. If not that, check the power supply and grounds.
The battery is fairly new. Volt meter is sitting at 14+ volts.
However, in park, I ran the RPMs up to about 4k to see if the volt meter would move. It didn't, but both lights went out and the transmission went back to shifting normal.
14V means its running. Test the battery, not hte charging system. load test it with the truck off. I've seen lots of dead cells cause similar problems. or too small of a battery
Next time it works badly, hook a booster cable from the negative post of the battery to the engine block. The cables on those trucks fail quite regularly at the crimp for the battery end, and it can be very intermittent. And frustrating to find, because they pass all sorts of load and voltage drop tests when they are working properly.
84FSP
UltraDork
1/27/21 7:51 p.m.
Wheel speed sensors can cause issues as well. Reasonable cheapish fixes.
Which 07? The new ones are known to have weird issues associated with corrosion of the mega fuse on the firewall by the battery. I've fixed a couple of weird unrelated problems with trucks (here in Texas, so no salt) by disassembling, cleaning, and reassembling with dielectric grease. If it's a classic then ignore this, I have no idea.
