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bill, dodge master tech
Category: Dodge
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Experience:  25 years with dodge drivability and electrical expert
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2006 Dodge Grand Caravan: liter engine..trouble codes..p0420

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2006 Dodge Grand Caravan with a 3.8 liter engine. It is putting out 4 trouble codes. P0420 P0404 P0403 P0406. It just started yesterday not having any power upon kickdown into a passing gear. It makes a loud spark knock noise when trying to get it into passing gear. It also does not want to shift into normal gears very well now during driving in town at regular speeds. I put a new EGR valve on it yesterday but no change. It had also used 3 quarts of oil since its oil change 3000 miles ago. I tapped on the converter and it doesnt rattle. Thanks

hi i'm bill
welcome to just answer
please remember I am NOT there in front of you! my answers are based on your information. first start with the P0420 which is a catalyst failure, these do not rattle when they fail they plug and restrict the exhaust flow, the positive test to determine if the cat is plugged is simply remove teh front oxygen sensor and drive teh van if it runs ok the cat is plugged this MAY be covered under federal emissions warranty IF you have under 80,000 if you are just over but under 100,000 miles call chrysler customer assistance and see if they will help (good shot they will)

as for the egr codes you MUST disconnect the battery to clear all the memory and force the engine computer to relearn the egr valve ,it learns the egr valve and compensates for normal wear during driving and if you do not do a battery disconnect the engine computer will think the old egr is still there and set false codes

as for the oil usage first the failed catalyst can cause oil burning due to excessive engine back pressure second a pcv valve that is sticking open will draw oil into the intake and cause more oil usage, third understand this engine uses some oil the standard for oil consumption is 1 quart every 750 miles due to the low tension oil control rings used.

Customer: replied 4 years ago.

It has 113000 miles. Would that catalyst possibly be covered for warranty? Also Which O2 sensor do i remove. the one just before the cat or the one closer to the engine? Thanks

the one before IS the one closer to the engine it is under the windshield on the rear exhaust manifold.

as for warranty well you can call chrysler customer assistance and see what they say, depending on how you present your case who you get and your attitude (the friendlier the better) you may get some assistance how much will depend on the person you get, i have seen them give a 150,000 mile grand cherokee a new window regulator, give a customer 2 cylinder heads AFTER some independent attempted a repair and screwed it up badly on the other side they have denied claims for assistance just just over teh basic warranty expired for no real reason.

Customer: replied 4 years ago.
It seems odd that it is the catalytic converter, but i can understand, can you please tell me what you would di if it was your van? I am going to disconnect the battery and then remove the o2 sensor and see if that helps. if that doesnt do it, could it be any other thing?

i see you provided a NEGATIVE rating can you explain as to why?since you have yet to accept the answer or done what i suggested yet, i could see the rating if you had done what i suggested and it failed to solve the problem BUT...

well with a cat code that means the cat is no longer working our diagnostic procedures the only fix is to replace the converter,if you use a cheap aftermarket one the code can comeback, i also usually change both oxygen sensors since they have a life of 100,000 miles and are usually damaged by a failed converter.

if that fails the only other thing would be a cracked and slipped flywheel the crank sensor tone ring is on the flywheel and it is common for it to break and slip retarding the timing the way we see this is with a GOOD data reading scan tool looking at the cam and crank sync if it is about 13 degrees negative this will cause retarded timing lack of power NOT always set a code and possibly cause the converter to overheat melting the insides.

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