I have a 97 XJ & i put a new crankshaft sensor on & it runs like new. I can let it sit & idle for hours & it runs great. I can drive it roughly 15 miles & the check engine light come back on saying crankshaft or camshaft sensor. I put another new crankshaft sensor on & it cranks after turning over maybe 3 times & runs great then after about 15 miles back to where i started. It has new distributor, rotary button, distributor cap, champion plugs, wires, coil, battery & fuel pump. Ive spent from $30 to $120 on each sensor. What is it that keeps killing my crankshaft sensor after only 15 miles?

 

have you replaced the camshaft sensor or as they called in my my 96 ignition pickup coil censor, its in with the distributor assembly.

also when I replaced my crankshaft I was informed to make sure I buy a genuine oem sensor and not an after market cause they don't last.

 

The cam sensor came with distributor so both are new

 

Chances are your new cam sensor is NOT Mopar, and is therefore highly suspect. Aftermarket sensors run from bad out of the box to lasting a few minutes to lasting a few months to lasting a couple of years.

OR, there is something wrong with your electrical system which is killing your crank sensors. I've never heard of that happening, but I suppose it's possible.

 

Symptoms are consistent with a poor signal from crankshaft position sensor. This sensor is mounted on the transmission bell housing. The transmission will be well and truly hot after about 15 miles of driving. So my educated guess from across the interwebs is that your aftermarket crankshaft position sensor is not heat resistant enough to withstand the temperatures around the transmission.

 

I went through all steps as you in tracking down persistent crank\cam sensor code. Read advice somewhere about ground, connections,harness issues...

Disconnected, cleaned, lubed every connector I could find, still problem.

​​​​Every ground point I could find, I removed, cleaned, installed stainless star washers if possible... Still problems.

Removed ecu, took apart looking for corrosion, failed connections... Still problems...

​​​... With car running... Go under hood and pull on each wiring harness, harness "t"... Wiggle, pull on whatever you can find.
As soon as I tugged on harness coming through firewall engine stumbled, then again, and again while tugging certain wires.
I split wiring loom looking for anything out of place.
Re-soldered a few factory splices... Have had NO hiccups, codes since! Even cured what I thought was a transmission issue regarding random harsh lock-up engagement.

For the past 1k miles, my $600 1999 Cherokee has been running perfectly... After sitting 2years with previous (original) owner unable to diagnose...she is finally back in service doing what she loves...riding around!

Hope this helps....
Jamie