Hey all, I’m having issues with my 08 Kia Optima. The speedometer and odometer aren’t working. I’ve replaced the vehicle speed sensor, PCM is good, and the cluster is good. Dealer inspected it, no corrosion or damage found. Anyone have ideas
Ever checked the wiring harness for loose connections
KiaDiva said:
Ever checked the wiring harness for loose connections
Not yet. Last thing I did was a visual check with the dealer, no corrosion or damage, but maybe I should check it closer
KiaDiva said:
Ever checked the wiring harness for loose connections
Definitely check the wiring. I had a similar issue on my car, and it turned out to be a loose connection
fabricia said:
How about the vehicle speed sensor, was that replaced
Yeah, I actually replaced the speed sensor. I also have a used PCM and a used cluster I haven’t tried yet. I’m thinking it could be something with the harness though
KiaTalker said:
What year is your Optima
It’s an 08, manufactured in 02/08. Still hoping to get this fixed without too much extra cost
Did you have the instrument cluster tested for functionality
melissasavant said:
Did you have the instrument cluster tested for functionality
Dealer checked it visually but didn’t find anything wrong. I haven’t tried another test yet
How about the vehicle speed sensor, was that replaced
fabricia said:
How about the vehicle speed sensor, was that replaced
If you haven’t tested the used cluster, that might be worth a try. The cluster should be plug-and-play
Sounds like a harness issue if all other components are working. Have you checked the connection from the VSS to the PCM
Kia said:
Sounds like a harness issue if all other components are working. Have you checked the connection from the VSS to the PCM
Good point. I’ll need to check continuity between the PCM and cluster, and from the VSS to the PCM. I’ll probably have to remove the air cleaner box to get to it
Kia said:
Sounds like a harness issue if all other components are working. Have you checked the connection from the VSS to the PCM
Removing the air cleaner box can definitely help you access the connections. Let us know if you find anything
Any updates
OptimaPrime said:
Any updates
I did some continuity checks. Tested continuity, voltage, and ground on both input and output pulse generators. Also tested the PCU fuse, which was fine
OptimaPrime said:
Any updates
Continuity is a good sign. Next step could be checking the signal continuity from the ABS module to the PCM. Sometimes there’s a splice in the wiring for the ABS to PCM connection
@howdyrobert
Interesting. I’ll need to take a look at the ABS harness. Dealer mentioned a pigtail that might be causing the issue. I’ll see if I can locate the splice
@howdyrobert
A faulty splice could definitely interfere with the signal. Make sure all connections are solid
Had a similar problem with my car. Replaced the PCM, cluster, and speed sensor but the issue was in the wiring. Had to trace each connection to find it
Flippa said:
Had a similar problem with my car. Replaced the PCM, cluster, and speed sensor but the issue was in the wiring. Had to trace each connection to find it
I’m hoping it doesn’t come to that. Continuity tests so far have been good, but I’ll keep tracing if needed