I have a 2006 Dodge Ram 1500 5.7 V8 Hemi. The past few weeks I noticed my RPM gauge falling below normal then go back up to normal range while sitting at red lights and stop signs. Well the problem got worse and the truck eventually started dying and the check engine light finally came on. I limped the truck to AutoZone where they checked it and said it has a Failed Crank Shaft Sensor. Well we replaced it and it is now even worse then before. Truck will barely crank and the RPM gauge will skyrocket and fall and eventually just die. Any ideas?? Thanks

 

If in fact the Crankshaft Position Sensor was bad and was your problem, here are some possibilities:

• Crankshaft Position Sensor replacement incorrect part
• Incomplete electrical circuits to Crankshaft Position Sensor. Either broken or shorted wires, poor connections
• New part is defective

Good luck and best regards,
Dusty


2014 Ram Big Horn 1500 Quad Cab 2WD, 5.7 Hemi, 8HP70, 3.92 LSD, factory dual exhaust, 20” wheels. Now at: 004300 miles.

 

Agreed. While not common, it's not impossible to replace a defective part with another defective part. And sometimes the defect on the new part will create a condition different then you were replacing the original part for. Get another sensor and double check the installation instructions to make certain you did not overlook something.

 

akaynance,

I'm sorry to learn of your RPM and stalling concern.

In some cases an RPM undershoot at idle and even stalling can be the result of low transmission fluid. Have you had a recent transmission service completed?

 

He claims that Auto Zone checked it with a scan tool and it was showing a bad Crank Sensor. Are you saying that the truck would throw the code for a bad crank sensor even if it was low transmission fluid?

 

Auto Zone has a bad, bad, BAD habit of erasing people's codes when they do the free scan. Did you get a printout of what codes were in there?


>>Your problem could also be mechanical. I think DodgeCares means that an external force can act on the rate of spin and cause a crank sensor code, such as a torque converter anomaly, a timing chain jumping a tooth or even a catastrophic misfire on one or more cylinders. Especially when the Adaptive Numerator gets wiped out (codes cleared) causing the misfire monitor to not log individual cylinders, in which case possibly ONLY a crank code would appear.

>>There is a well documented issue with aftermarket crank/cam sensors (in my circles anyway)

>>As a general rule, we have the best aftermarket luck from Borg Warner sensors.

 

I, too, am curious how a transmission low fluid condition could effect a fluctuating idle and/or stalling condition, must less a crankshaft position sensor (CPS) fault.


As to aftermarket parts, I can name a dozen people that have had issues with non-OEM components. In fact, my son had a CPS issue with an older Mopar a few years back.


Regards,
Dusty


2014 Ram Big Horn 1500 Quad Cab 2WD, 5.7 Hemi, 8HP70, 3.92 LSD, factory dual exhaust, 20” wheels. Now at: 004500 miles.

 

On my 06' i had a weird hesitation issue that was on the engine side (confirmed through the tach). Someone mentioned to chec the trans fluid which was less then 1/2 a quart low. I figured their was no way it was the issue but topped it off. Problem immediately went away and never came back. So i know first hand these trucks are VERY sensitive to the trans fluid level.

I can vouch for that too. I had no codes displayed when i decided to change all 4 O2 sensors on my Ram at 100k as preventative maintenance. I put 4 new Bosch sensors in and immediately threw a code for a bad O2 sensor. I replaced the one that was bad and then got another CEL for another one. Did some research online and found Ram's do NOT like Bosch O2 sensors. So i bought the Mopar units (NGT) and the all was well.

 

Isn't this in the wrong section??? This is a 3rd gen model. He may get the answer he needs more quickly in that forum.

 

Well sheeuut I thought he had a 2009!!!


Welcome to 3rd Gen!