96 Dodge with code issues


The check engine light is on in a 96 Dodge Intrepid with a 3.3l. I have used the MIL method of reading the codes and I have read two codes of 12 and a 72. According to Chilton’s:

12-Battery input to PCM was disconnected with last 50 key starts.

I know the battery has not be disconnected for some time and it is in good condition. Sometimes the car may sit for 4 or 5 days without being started but the battery sould not be so low that the PCM does not get enough power to keep its memory. Any advice on what is going on?

72 - Rt rear catalyst or Lft front catalyst. I assume this is an O2 sensor. How can I easily narrow down which one it may be? Since the sensors expensive and are tough to get out I want to only replace what I have to.

Any advice is appreciated.

Thanks in advance.


Have the PCM scanned with an actual OBD 2 code scanner. You’ll get a more precise code. Try AutoZone or Advanced Auto Parts- they do it for free around here.


I went to Advanced Auto and the code they read was P0432 main Catalyst below Threashold. Bank 2.
This corresponds to the 72 code I got when using the MIL method and it narrows it down to Bank 2 (I think it is opposite bank of #1 plug).
This is either the down stream O2 sensor or the Catalytic converter is at or near the end of its life. I am not so sure which one. If it is the Cat what is the best approach?

There was no reference to the 12 code I got when using the MIL method.

Any advice?


If it is the converter you replace it with an after market; much cheaper and just as good.


I reset the code and for a few weeks the light stayed off. When it came back on I went to Autozone to get it read. Again it was PO432 and on the print out it offered probable causes:

  1. Catalytic converter defective (possibly due to the below)
    2.Engine misfire or running condition
  2. large vacuum leak
  3. Engine oil leaking into exhaust

Does this mean the catalytic converter is definately bad? Or could one of the other listed causes, if fixed, solve the code light from coming on?

Ok, so I will pull the bank #2 plugs and look at them to see if it looks like any are misfiring or burning oil. The plugs and wirers are about 2yrs old and about 12k miles on them. They should be in decent shape. The engine does seem to idle a bit rough at times. Could that be the cat?
Any Suggestions on a reasonable plan of atack? Replacing the cat is expensive (part alone is $230) and the studs and bolts are rusted and will be near impossible to remove without breaking. Any suggestions on tackling this issue? After all it is a 96.


You asked about code 12. Dodge products always give a code 12 using the OBDI method. This code should always be ignored, along with the code 55 at the finish.


Thanks. The manual explains the 55 always showing but not the 12.

I am hoping to get some advice on the smartest approach to take moving forward. I know that the codes don’t always point to the root of the problem and that is what I suspect here.


I checked the plugs on the #2 bank and they seemed normal. Slightly redish color with next to no gap wear. I noticed the coolant was low and I filled it and added a bottle of Barrs. There was a very small drip type leak underneath. Appears to be from somewhere on the engine block. The car seems to ride ok with no acceleration issues. If the Cat was going wouldn’t the acceleration be poor? If it is an occasional missfire it may be an injector issue. I will add a can of Cheveron Techron fuel cleaner and see if that keeps the 72 code from coming on.

Any advice appreciated based on this new info? Thanks!


The catalytic converter has no effect on how the engine runs, unless it gets stopped up. A rough running engine can cause the catalytic converter, and oxygen sensors, to fail; but, don’t jump to that conclusion, yet.
WHEN does the engine run rough? Knowing when it runs rough may help to determine WHY it runs rough.


The engine roughness is subtle and it is only noticable at idle. As a shade tree mechanic is there a way to test the O2 sensors. I know I can check for an open circuit or short. However if this was the problem a direct code would have been triped. The Barrs seemed to take care of the coolant leak.
I am going to try the Techron in the gas next.

Thanks for any assistance.