Chevy Cobalt Forum banner

Status
Not open for further replies.
1 - 8 of 8 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
The speedometer has started jumping around while car is in park or while maintaining speed. It'll affect cruise control (obviously) and will sometimes even cancel it. It will also sometimes cut power after it starts jumping around. All other gauges are fine. A/T shifts fine. Again, not experiencing symptoms during acceleration.

FYI I have been putting off a P0135 CEL (upstream O2 sensor I believe) since car registration will be current for several months. As of this post, though, I couldn't tell you if a second CEL code has popped up.

2005 Cobalt 2.2L A/T Base, non-ABS
-Injen Short Ram Intake
-B&M A/T Shift Kit
-Dash Cluster from Cobalt 2.4L

I included some links to threads addressing somewhat similar symptoms. Some with solutions, some without. Thanks in advance for your help!

http://www.yourcobalt.com/forums/problems-service/63690-jumping-speedometer-loss-power-hard-jerky-shifting.html

http://www.yourcobalt.com/forums/chevy-cobalt-owners-lounge/65098-speedometer-jumps-around.html

http://www.yourcobalt.com/forums/transmission/64522-cobalt-issue-speed-sensor.html

http://www.yourcobalt.com/forums/problems-service/30702-oxygen-sensor.html
 

·
Super Moderator
Joined
·
11,821 Posts
P0135 would not cause your speedometer to bounce.

Bad ground or VSS Vehicle Speed Sensor on transmission output shaft passenger side.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #3
It wouldn't be any of the BCM plug issues mentioned in the other threads?

Not complaining. I'd much rather just futz with a sensor than a whole computer module...
 

·
Super Moderator
Joined
·
11,821 Posts
Well it could but if you had GMLan breakdown at the BCM you'd have other symptoms. I think your issue is somewhere between the "VSS" and the PCM. Most likely corrosion at either end.
 

·
Super Moderator
Joined
·
11,821 Posts
If it totally fails yes but an intermittent one could take a while since it needs to be nad for something like 10 seconds.
 

·
Registered
Joined
·
1 Posts
I just finished fixing my multi symptom mess on my 2010 Cobalt. If you are experiencing multi symptoms you must check through all the wiring harness under the hood. The plastic conduit on much of the wire harness was cracking and hardened. I finally found a clump of wires butted up against an edge of a part attached to the engine. The plastic conduit looked fine from first view, but when I was checking some wires for continuity I got some changes as I wiggled some wires and finally found those wires shorting onto the engine part. The short caused an engine manifold pressure code, an exhaust solenoid code , and a shift solenoid B code that was causing horrible transmission shifting problems. These were low and high circuit codes because those wires were shorting directly to ground and probably to each other. I coated the wires with silicon rubber and put new conduit on, and plastic tied them off of the engine. All problems solved.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #8
I actually found a similar solution to my problem. After finding the videos below on YouTube, I discovered the harness near the receptacle for the oil filter had about 8" missing conduit that had disintegrated. Lo and behold, the VSS wires (purple and yellow braided together on my '05 2.2 auto) had worn insulation from a sharp edge on the oil filter receptacle and I believe were shorting to ground and causing my wonky speedo signal (and eventual shifting an driveability issues).


 
1 - 8 of 8 Posts
Status
Not open for further replies.
Top