View Full Version : Upshift Light??

02-26-2009, 05:14 PM
I know the upshift light means no signal from the crank sensor.
I have replaced that sensor twice (one used and the last one is new) and still have upshift light stay on.
Which brings me to this, Other than a bad crank sensor, what would cause the signal from the crank sensor to stop?, causing the upshift light to stay on, (ECM)?
The engine would stop running and the light would stay on while trying to start..
After waiting a few minutes it would start. Until recently it would not start at all and the light stays on while trying to start.
A crank sensor should not go bad intemitly, they should just go bad, right?
The harmonic balancer is just 2 years old, had them break on me so been there done that!!.
Need help to figure this out!!

02-26-2009, 05:20 PM
Trace the wiring. Look at the connections near the sensor. Make sure they are all secure and clean. Make sure the air gap between the sensor and the vane wheel, on the back of the HB, is OK and that it isn't being clobbered by a bent vane.

02-26-2009, 05:25 PM
My initial thought would be to check the wiring to insure it has not been rubbed partway through by a belt. Also check the connections to insure they are not corroded and have continuity through them. It would be a pain, but continue to follow the wiring back to the firewall to make sure that the wiring is not the issue.

I'm sure that you're aware that the crank sensor has to be positioned just right or it will make contact with the veins that are supposed to pass through it. Maybe an issue?

Every now and again, you can purchase a bad sensor, but 2 in a row would be highly unlikely.

Not sure when it gets to the EEC. Someone else would have to chime in if you've checked all the wiring and sensor and they are good. I'd be at a loss at that point.

Not sure if it helps, and I'm sure it's not what you want to hear. Hope you get it worked out though.

02-26-2009, 05:33 PM
Thanks for the fast replies!
I was able to watch the vanes, while a friend turn the engine over.
That was all good!
I am going to check the wiring and look into the sensor circuit to see what i can find.
Will keep you guys informed!

02-27-2009, 05:23 AM
FYI, The crank and cam sensors circuits do go through the DIS.
Still working on my situation.