2002 Denali-Trans Temp Gauge Bouncing

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Marshall2002

TYF Newbie
Joined
Dec 8, 2018
Posts
23
Reaction score
21
The trans temp gauge in my 2002 Denali bounces up and down from 100 to normal. When I say bounce, I don’t mean changes in temperature, but fast enough to mean erratic connection. Should I start the sending unit or gauge?
 

sealandsky

Full Access Member
Joined
Jun 28, 2019
Posts
510
Reaction score
251
Location
Minneapolis, MN
I'd start at the sending unit, but check electrical connections back from there. Most likely a bad connection, break in wire or corrosion.
 

rockola1971

Full Access Member
Joined
Dec 29, 2016
Posts
2,439
Reaction score
3,128
Location
Indiana (formerly IL)
Dont forget the connection behind the instrument cluster also. They sometimes get oxidized and cause a bad connection. A pencil eraser usually does the trick. Could be a bad solder joint on the cluster too.
 

rockola1971

Full Access Member
Joined
Dec 29, 2016
Posts
2,439
Reaction score
3,128
Location
Indiana (formerly IL)
Check live data w/ scanner. If it's intermittent, start looking on the temp sensing end. If it's not, start checking on the display end
Great point. The live data will rule out one side or the other. If the live data is bouncing around like the gauge is then indeed the sensor or its wiring harness to the PCM is the problem child. If the live data is steady as a rock then all of that part of it is fine and the problem is strictly in the Instrument cluster all the way back to the output of the PCM that feeds the tranny temp signal including that wiring harness part of it. Sounds like a blast!
 

Forum statistics

Threads
130,456
Posts
1,832,981
Members
94,096
Latest member
Noble_1
Top