2001 Dodge Neon misfire codes

Tiny
AMANAMAN1
  • MEMBER
  • 2001 DODGE NEON
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 137 MILES
2001 Neon 2.0, 137K, auto trans

A little background:

Car was running fine, no issues, no engine lights or codes. I did some preventive maintenance including timing belt, water pump (Oh what fun THAT was!), Crank position sensor, cam position sensor, coolant temp sensor, and spark plugs. Car ran fine afterwards for a couple weeks around town and then week 3 when on the highway for about an hour the MIL light came on. Code was 0300 - random misfires. Car didn’t actually seem to misfire as it didn’t*****, sputter, kick, backfire, or anything else you’d expect with an obvious misfire. Went ahead and then replaced the plug wires and ignition coil and checked the already new plugs for anything obvious…all seemed well. Reset the code and car ran fine with no codes for a few days around town again and then when on the highway again for about another hour, MIL light came back on. Codes read 0300 and 0302,0303 for cylinder misfires. Again, no obvious signs of an actual misfire as car never acted up or ran funny. It has always ran fine before and during this issue.

Question is this:

Does the vehicle need to have a cam/crank relearn procedure initialized or does the PCM just adjust itself as time goes on? Or, is there something else I may have done or didn’t do that could be causing the random misfire codes? I’ve heard it both ways that yes it needs a relearn and no, it doesn’t because this PCM doesn’t even allow for it as it just adjusts itself anyway. I’d like some real advice from someone in the know before I go out and buy a new scan tool that has the relearn capability. I’m a handy guy but all I’ve got now is just a reader, and I don’t mind getting a new one with more capabilities, but just really need some good advice first.

Thanks,

Brian
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Thursday, February 3rd, 2011 AT 10:12 PM

6 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
When the timing belt is replaced, the cam / crank relearn procedure needs to be done on this vehicle. Connect the scan tool to the data link connector under the lower left side of the inst panel. Turn the key to the run position (engine off) and select cam/crank relearn procedure by accessing engine diagnostics. Select miscellaneous then crank/cam relearn and follow the scan tool screen.

If you haven't done this (you said you didn't) I feel confident that is where the problem is coming from.

Let me know if it works or if you have other questions.

Joe
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Thursday, February 3rd, 2011 AT 10:57 PM
Tiny
AMANAMAN1
  • MEMBER
Ok, I'll pick up a new scan tool with that capability and do the relearn. I guess I forgot to ask, is it normal that it would pop up a misfire code if the relearn isn't done after the timing belt or should it have shown a different code such as a timing issue?
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Friday, February 4th, 2011 AT 12:05 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
It is normal. What is happening is the cam / crank sensors are not working in sync. At low RPM's the chances of a misfire are slim. However, when you take it out for a long period of time (higher speeds) it can set the code. The reason you didn't feel the misfire is because, in reality, it wasn't a true misfire. It is a timing issue the computer thinks is a misfire.

Before you purchase the scanner, contact your local dealer with the VIN and ask if there are any updates that need programed into the computer. Off the top of my head, I can't think of any for a 2001, but I would hate to see you spend the money on a scanner only to find out you have to take it to a dealer for an update. The scanners are not cheap.

Let me know if you have other questions.

Joe
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Friday, February 4th, 2011 AT 12:26 AM
Tiny
AMANAMAN1
  • MEMBER
Thanks a bunch Joe. Right now my daughter has the car 2 hours away at school so it may be a few weeks before I can get it done. I'll let you know.

I really appreciate the concise and detailed explanation and responses. It really helps the determined do-it-yourselfers like me. By the way, I've got another issue with another vehicle I'd like your advice on but I want to make sure you get the donation/request. Is there a way to make sure you get it?
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Friday, February 4th, 2011 AT 12:42 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
I'm glad to help. As far as a do it yourselfer, it sounds to me like you know a heck of a lot more than that. You basically rebuilt the vehicle.

Take care and let me know if you have other questions.

Joe
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Friday, February 4th, 2011 AT 1:10 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
One last thing, I just reconfirmed what I told you. I checked the manual. When replacing the timing belt, the last step is exactly what I told you. Now I feel even better with my answer.

Take care of yourself and let me know how things go.
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Friday, February 4th, 2011 AT 1:14 AM

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