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Crankshaft position Sensor A Circuit Intermittent


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komodo
New User

Jun 29, 2013, 5:18 PM

Post #1 of 2 (3209 views)
Crankshaft position Sensor A Circuit Intermittent Sign In

I received a check engine light after a false start with my Jeep. I used an OBD2 tool and found the following trouble codes,

P0300 Random Misfire Detection
P0339 Crankshaft position Sensor A Circuit Intermittent
P0335 Crankshaft position Sensor A Circuit

My gas tank was almost empty and I had not used the car for 2 weeks, I think I got some humidity in the gas tank so I filled it up and added a bottle of fuel injector cleaner, it’s getting better after 2 days of driving around. This has happened last year and it solved the problem. However the crankshaft error codes are new.

When I turn the key fast, the engine cranks for about 4 or 5 seconds then it starts, when I turn the key slowly, it starts right away.

I suspect that the crankshaft is defective or it needs cleaning, is this correct?

2005 Jeep liberty limited
Automatic
Gas engine
V6, 3.7 L
Purchased in Canada
80.000 miles


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Jun 29, 2013, 5:32 PM

Post #2 of 2 (3205 views)
Re: Crankshaft position Sensor A Circuit Intermittent Sign In

Probably check out the crank sensor circuits first. If they check good, you may need a scope to see what the crank sensor signal is doing.

The crank sensor is used by the engine computer to determine the position of the crankshaft and the speed of the crank shaft. The sensor is a hall effect sensor that sends a digital signal to the computer.

You have a circuit code and intermittent signal code for the crank sensor, so injector cleaner isn't going to resolve that. The misfire code and the crank sensor codes are probably related. The intermittent crank sensor signal could be making the computer think misfiring is going on.

If your interested in testing a crank sensor and its circuits, you'll need a volt meter, lab scope or graphing multimeter, and wiring diagram.

Here is a video on digital crank sensor testing if your interested.

http://www.youtube.com/watch?v=yp_kK6U8a64





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