greenhorn
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Joined: Dec 2010
Posts: 4,858
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From: MA
P0420 is a 1/1 Catalytic Converter Efficiency, drivers side upstream.
The OBD system tests efficiency by comparing the upstream/downstream O2 sensors. If they're good, you probably have a bad cat. Which did they change before?
Also, if you have Bosch O2's, Dakota's hate them.
The OBD system tests efficiency by comparing the upstream/downstream O2 sensors. If they're good, you probably have a bad cat. Which did they change before?
Also, if you have Bosch O2's, Dakota's hate them.
All Star
Joined: Mar 2013
Posts: 783
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From: Eastside Tucson AZ
Hello everybody I have 1998 dakota 2wheel 3.9L vehicle Make a long story short, the truck have been stalling and cutting off now for almost 2-3 weeks. Changed the spark plugs, wires distributor cap&rotor, air filter,switched to high-octane gas, had 2 mechs check it out, one said it was my pcm, other one said the truck has a ghost in it.Checked the throttle position sensor, it works great, can hear the fuel pump engage when switch is turned on, fuel pressure gage test was good, no vacuum leaks according to the second mech,Oh truck starts choking after 30-35 min ride to work then just shuts down, very difficult to restart{recrank} again, HHHHEEEELLLLLPPPPPP
Check the plugs for the PCM, take them out, inspect them for corrosion and plug them back in.
The two mechs (especially the one who believes in ghost) are *******. Dumbas$es! I'd never go back to them. You MIGHT have to take it to a Dodge/Chrysler dealer and pay for a diagnosis. Beats tossing money at the engine.
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Joined: Jan 2014
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Thanks Dak and Brian, when I had my cat changed out I didn't think to ask the guy what kind of sensors or new cat I was getting put on, well I will just take it to a proffessional shop tomorrow and I 'll let ya'lllll know how everything turned out. thanks once again.
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Well took it to a professional [reputable] electrical/mechanical, builds&race cars shop yesterday, and they ran test after test after test diagnostic after dianositic and they said they could not find anything wrong.So they ask to come and drive it and maybe "the symptoms" will reappear again. I'll let ya'll know the results.
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Well folks, got a call from the shop this morning and the final phase of this mysterious journey is now completed. It was the pcm, so that being said now comes another phase of this mysterious post journey, finding a reasonbly [sp] price pcm??? Stay tuned