Mechanics

I NEED TO REPLACE BOTH MY CRANKSHAFT SENSOR AND MY CAMSHAFT SENSOR ON THE 3.3 LITER , BUT I CANNOT LOCATE THEM.

2002 Chrysler Town and Country • 158,000 miles

Are there any diagrams available anywhere on the web? I have been searching all day. The only directions I get are general locations. Please help.
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Courpay
June 6, 2012.




What's the symptoms? Two sensors are not going to fail at the same time. The crankshaft position sensor is on the transmission bell housing near the firewall and rear cylinder head. It requires a thick paper spacer to set the critical air gap. Many aftermarket sensors have a thin plastic rib molded on instead of that spacer.

The camshaft position sensor is somewhere around the thermostat housing. I've never replaced one and I own two vehicles with that engine.


Caradiodoc
Jun 6, 2012.
Well I am getting two engine codes a P1391 and a P0601. Some trips the car runs fine and then on the very trip it stalls out, or doesn't want to keep running at all. I have replaced all the plugs and a starter recently. If I accelerate, it sometimes sputters and wants to cut out. But then continues on, sometimes it sputters and does stall out. So I figured one or both of these sensors may be the problem.


Tiny
Courpay
Jun 6, 2012.
First of all, diagnostic fault codes never say to replace parts. They only indicate the circuit or system that needs further diagnosis. Second, throwing parts at a problem is the most costly and least effective way to diagnose a problem unless you already have the parts. There's a much better way of figuring out if a sensor is failing but it requires a scanner that can display live data. I use the Chrysler DRB3 but there are a lot of good aftermarket scanners out there that do almost as much.

The two sensors are listed on the DRB3 as "no" or "present" to show whether those signals are being received. That makes real quick work out of a no-start condition but when you have an intermittent loss of one of the signals, there is a record feature that is used during a test drive. You press the "record" button when the problem occurs, then you can play back the data stream later to see what happened. Since that data travels through the scanner's memory, the recording actually starts a couple of seconds before you pressed the button.

The next best thing is those fault codes but the P1391 suggests the Engine Computer doesn't know which signal is being lost. Whenever it sees one signal, it knows the other one should be there too. Connector and wiring problems account for about half of the fault codes, and a defective sensor about the other half. The two sensors share a common feed wire and a common ground wire. If either sensor becomes shorted internally or if the feed wire becomes grounded, it will kill the 8.0 volt supply and the Engine Computer will shut it down to protect it. At that point the engine would stall and not suddenly start up again. Once the short is gone, you have to turn the ignition switch off, then restart the engine to reset the 8.0 volt supply.

There are other ways for sensors to fail that do not cause the power supply to shut down. One thing that bit me was not using that paper spacer on the end of the crankshaft position sensor. After replacing a dozen transmissions, I felt confident in setting the air gap by feel, but on the 13th transmission job, that one developed an intermittent stalling problem two weeks later. In response to the intermittent loss of crank signal fault code, another mechanic replaced that sensor and solved the stalling, but I have to assume it was because I didn't use that spacer.

If you're going to guess at a solution, start with the crankshaft position sensor. Never replace two or more things at once. If you end up with a no-start condition due to some mistake or a defective new part, you want as few variables as possible to contend with. Camshaft position sensors are a common problem on Neons and Intrepids, but I've never replaced one on a 3.3L / 3.8L.
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Caradiodoc
Jun 6, 2012.
Thanks for all your help and advise Caradiodoc, I really appreciate it, I went out and got the Crankshaft sensor, but am still having a bear of a time trying to locate where it goes. You say its on the bell housing near the firewall. So is this something I need to get to from under the Van? Can I get to it from the front of the van? What is it by? Is it facing the firewall? Is it near the starter? Left? Right? Is it facing the radiator? I feel this is like trying to find whats inside Al Capones vault. If it is facing the firewall, do I need to remove the windshield washer mechanism to get to it? I am seeing many sensores, but not this one. Why is there not a clear picture anywhere on the web for this? I appreciate your help.

Remember I am not a mechanic by trade so as I slide under the van give me direction like where is is in relationship to the say oil pan or transmission pan? I have seen posts saying you can see it if you remove the battery tray, I have seen other posts saying you can see it if you remove the air filter attachments and follow the 1/2 inch wire harness South? These are on opposite sides of my car anyways?


Tiny
Courpay
Jun 7, 2012.
It's on the back side near where the steering column comes out of the firewall and goes into the rack and pinion steering gear. If you look at where the starter attaches on the front, look an inch or two towards the driver's side on the bell housing, then find the matching point on the back side. Here's a photo of the part from rockauto. Com.

I left the dealership in '99, and I see this is a different design sensor than what I'm familiar with. There's no way to use that paper spacer I mentioned with this one. I have another Chrysler expert stopping over in a few minutes. I'll ask him if they moved the location of this sensor. I'll also keep trying to locate a better picture of its location.


Caradiodoc
Jun 7, 2012.

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