Hit a Bump Took a Dump

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Coming home yesterday on a road I don't use a lot. It's always been a little rough, but geez it's getting bad. Hit a patch of concrete that was like a washboard. Suddenly I hear a ding, look at the dash and see 4 lights on. Check engine and some other crap. Truck loses power, but doesn't die. Giving it about 3/4 of the pedal I was able to maintain around 10 MPH. Pushing pedal down further did no good.

Got it off into a parking lot, look under the hood. Nothing looks amiss. Idling nicely. Shut it off, start it back up and drove home without any further incidents.

Pulled the codes and shut the CEL off. Codes: PO339 Crankshaft sensor intermittent and P1618 DTC definition not found.

I'm thinking maybe I got a loose connection on the crank sensor. Can someone tell me where it's at please? Or if anybody has any other ideas I'd sure like to hear them. Truck is 2014 with Pentastar 3.6.
 

Ken226

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Coming home yesterday on a road I don't use a lot. It's always been a little rough, but geez it's getting bad. Hit a patch of concrete that was like a washboard. Suddenly I hear a ding, look at the dash and see 4 lights on. Check engine and some other crap. Truck loses power, but doesn't die. Giving it about 3/4 of the pedal I was able to maintain around 10 MPH. Pushing pedal down further did no good.

Got it off into a parking lot, look under the hood. Nothing looks amiss. Idling nicely. Shut it off, start it back up and drove home without any further incidents.

Pulled the codes and shut the CEL off. Codes: PO339 Crankshaft sensor intermittent and P1618 DTC definition not found.

I'm thinking maybe I got a loose connection on the crank sensor. Can someone tell me where it's at please? Or if anybody has any other ideas I'd sure like to hear them. Truck is 2014 with Pentastar 3.6.

According to AI: p1618 is an ecm voltage error on the 5v reference voltage bus, internal to the PCM.

Best guess, the 5v on your crank sensor got intermittently shorted to ground while you were Dukes of Hazard'ing. ******.

Grab a flashlight and crawl under. Inspect the wiring and connector, especially anywhere the wires can rub metal parts.

 
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HotDamnGotaRam
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I do try and avoid this activity ->

View attachment 581634

Sorry can't help with the sensor location.
That looks like me in my Chevelle SS after hitting the Kankakee River bridge at 150 mph. Left a 440 Road Runner in the dust, but nearly met my maker. Young and dumb. Good times???
 
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HotDamnGotaRam
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OK, I'll admit been sort of ignoring this since it hasn't happened for a while, but yesterday it happened 3x. Going over moderate bumps. Nothing real bad.

Got under there today to take a look and don't see anything that looks bad. Could it be the sensor itself is going bad or am I just missing something? Plug seems to be on tight and no breaks in the plastic loom. All wiring inside, don't see any bare wires sticking out.
 

Rado

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following
Good luck tracing a issue that happens once in awhile
 
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HotDamnGotaRam
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Sometimes we survive despite our best efforts! I once went into a river at 115 MPH.

You got that right. This wasn't my only incident. Blessed, maybe cursed, with dozens of fast cars back when wasn't much more than a teenager it's a wonder I'm still here.

Another time, I'm cooking down a 2 laner doing 90 in a Trans Am, at night. Nobody around. Suddenly some knucklehead turns right out in front of me. Car coming, my only option was hitting the ditch. Thank God it was shallow. Passed the car on the right and popped out of it unscathed. If it was deeper or there was a tree, who knows....

Another time driving like a goober, at night again. In a 400 powered Grand Prix, hit a patch of ice goiing about 50. Right out into a cornfield. There was one break in the treeline and I deftly slipped right through. Luck, not skill. Again no damage to the car or occupants. We did have to crawl out the windows tough and hoof it back to town to find a friend with a 4x4. We were buried in 2' of snow.
 
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HotDamnGotaRam
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Check ALL your ground connections between the engine and frame / body / battery are tight and clean with no corrosion.

Thanks for the idea. hadn't though of that. Wouldn't bad grounds cause other issues too though?

Anybody think it would be smart to just swap out the sensor? I read they have a magnet in them that can get weak with age. I just hate throwing parts at something hoping to get lucky.
 

04fxdwgi

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Thanks for the idea. hadn't though of that. Wouldn't bad grounds cause other issues too though?

Anybody think it would be smart to just swap out the sensor? I read they have a magnet in them that can get weak with age. I just hate throwing parts at something hoping to get lucky.
Grounds will cause all kinds of odd problems. No way to predict which ones. If the sensor tests bad, then absolutely change it. Intermittent problems are the worst to chase down, especially if you don't have a second set of hands available.
 
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HotDamnGotaRam
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Still working on figuring this out. Had one day when it went into limp 10x. Then the next 4x I drove it, only did it once. So far I've found two obvious grounds on inside of fenders. Cleaned them up real good. I know there's at least 2 or 3 more sneaky ones that haven't found yet. Decided be a good idea to clean battery cables. Pulled them all, cleaned the posts, and connectors, tightened it all back up with a little dielectric grease. Two of the little cables actually moved when I bumped my hand into them, so obviously not that tight. After doing nothing more it seemed good. Now I know it's not fixed, but seems better. Broke down and ordered NGK crank sensor. That's a good one, right? Most everyone seems to think it's that sensor or the plug, so that's what's next. Hope I get lucky. From what I've read the sensors all share the same 5V circuit and if any of them shorts it effects them all.

Something else I noticed is what looks like fuses in the battery clamp? Never seen anything like this before. One of them actually looks kinda funky. Could this be part of the problem?
 

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04fxdwgi

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Still working on figuring this out. Had one day when it went into limp 10x. Then the next 4x I drove it, only did it once. So far I've found two obvious grounds on inside of fenders. Cleaned them up real good. I know there's at least 2 or 3 more sneaky ones that haven't found yet. Decided be a good idea to clean battery cables. Pulled them all, cleaned the posts, and connectors, tightened it all back up with a little dielectric grease. Two of the little cables actually moved when I bumped my hand into them, so obviously not that tight. After doing nothing more it seemed good. Now I know it's not fixed, but seems better. Broke down and ordered NGK crank sensor. That's a good one, right? Most everyone seems to think it's that sensor or the plug, so that's what's next. Hope I get lucky. From what I've read the sensors all share the same 5V circuit and if any of them shorts it effects them all.

Something else I noticed is what looks like fuses in the battery clamp? Never seen anything like this before. One of them actually looks kinda funky. Could this be part of the problem?
Looking at that pic, those connections need some love. I would consider those "bad" connections and refurb them.

I would not use dielectric grease on the connections because dielectric is an insulating grease.

I use this conductive stuff on all electrical connections / grounds and battery terminals on vehicles and marine equipment / boats and have never had a corrosion / rust problem on connections.. We used it on the 10,000 amp buss and UPS connections in data centers and telecom facilities.

1782897049515.png

 

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