stix

Today while driving, I noticed the whole panel cluster with temp,tach,speed,etc going krazy, up and down, flashing lights, beeping, tach jumping from zero to 1500, all kinds of stuff---what wrong? It did it at Idle as well as speed.

I have a 99 2500 4x4 ctw 173000 miles with the 6 speed q cab long bed.

thanks

Stix

JyRO

stix - I just recently been having the tach drop to 0, then after sometime come back. I can hear what sounds like a relay clicking from the fuse panel on the left end of the dash. Sometimes the tach won't fall all the way to 0 before it comes right back. For me it usually happend about 1/4 to 1/2 mile after starting out on a cold engine. And doesn't seem to happen at all once the truck is warmed up. I'm also getting the check engine light and P1696.

ironman

crank position sensor failure can cause these symptoms. Unplug and plug it back in.

Geico266

Ditto, I had to replace mine just a few days ago, but only the speedo & tach were affected by a bad CPS.

It is located on top of the rear differential.

JyRO

Thanks. Further searching has led me to the crank position sensor. A couple questions:

1) How much does a sensor cost?
2) Where is the sensor located?

The reason I ask about location is because the ABS sensor is located on the top of the rear differential. And, the rear diff turns linearly with speed ... meaning sitting at a stop light with the engine idling, the tach would be at zero. The rear diff doesn't seem like the right place to put the cps.

ironman

crankposition sensor is located on crankshaft damper on top. Just unplugand plug it back in.

JyRO

I did a search and read where the cps was located behind the starter (starter must be removed). I even found instructions. Maybe its model year dependant?