'94 concorde no start: codes 42 and 43

Last Edited By Krjb Donovan
Last Updated: Mar 11, 2014 07:45 PM GMT


QUESTION: i have a 1994 chrysler concorde and have several ongoing issues with it....but most recently it had trouble starting. i did as you instructed and got the error codes. they are..... 21 33 35 42 43. i see one of them has to do with the oxygen sensor.... and per my uneducated research..... i see there is more than one oxygen sensor. i also found that one or more of them is near the catalytic converter. we recently had trouble with that componet. would that be an issue with its neighboring fuel sensor or sensors? im trying to narrow down options in choosing what sensor to try and change first to fix the issue as we will be doing the work ourselves out of necessity. could you possibly direct my ramblings toward an ameture solution for a poor dummy like me? thanks in advance!

ANSWER: Hi Mary nell, The two codes of relevance to the no start/hard start are 43 and 42. The others: 21 is about one or the other upstream oxygen sensors not working properly but that is not involved in starting or warming up the engine and only comes into play after operating temp is reached. These are upstream sensors mounted on the side of the exhaust manifolds proper. There are no downstream sensors in this model year (which would otherwise be nearer to the catalytic converter as you surmised). 33 is about the a/c compressor clutch circuit, and 35 is about the low or high speed fan relay circuit. The 43 says that one or more of the three primary circuits of the spark coil pack is not working properly. This could either be a wiring issue or the coil pack itself could be faulty. If you have a digital volt-ohm meter I can tell you how to measure the coil windings and verify the wiring to pinpoint the cause. The 42 says that the circuit that activates the autoshutdown relay has a problem, and that too is just a coulple of wires and a need to check them for continuity and for voltage supply as well as the relay contacts themselves. You could start by switching that relay with another one of the same part number which is not crucial to see whether that helps with the not start. It is located in the rear/inboard corner of the power distribution box under the hood. Let me know if you have the meter and we can then go through what to check on the ASD relay circuit and ignition coil pack circuits. The other codes should be dealt with later. Let me know if you have the 3.3L of the 3.5L engine. Roland

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QUESTION: oh my god how helpful! wow! ok..... here is the info... first of all i have just been informed the car is a 1993. i have told you previously it was a 1994. we do not have a volt ohm meter, but have been told we can rent one from a parts store. also...i have just been informed that the car no longer has a catalytic converter nor oxygen sensors on the exhaust system near the converter.....and it did at one time have both. they were removed due to malfunction about five months ago. they were replaced with a plain old muffler. ( this is a luxury we enjoy in a state with no emissions laws apparently) we are going to try the relay change out. ill let you know what happens. i really appreciate your help. ill be sure to rate you if it helps you.

ANSWER: Hi Mary Nell According to the '94 manual there are no downstream oxygen sensors at the converter, so I don't believe that is the issue with the 21 code. Each sensor is mounted on the manifold in the center at the main common common outlet pipe. It looks like a spark plug but has four wires. It is likely that one or the other of the upstreasm sensors because of its very fragile wires is the cause. So look carefully at them. I would wonder, unless the rental charge is really low, whether it might be more economical in the long run to buy a volt-ohm meter for under $30? roland

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QUESTION: I just found out the car is actually a 1993. It is a 3.5 liter. We have switched out the relays... and that does not fix the issue... the car will still not start. I do have a volt ohm meter now. You had mentioned that it may be helpful and you had directions as to how to check the ignition coil. I'm really not sure where to go from here. Thank you for all your guidance.


Hi Mary Nell. It appears that we have two question threads going. I answered the other one on Monday as follows: "The first simple test is turn the key to the run position and listen for the sound of the fuel pump inside the gas tank, a hum that should last for about 1 second. If it doesn't make that sound then either the relay or fuse B in that box in the engine compartment or fuse 18 in the box behind the left end-cap of the dash would be suspect of being blown. So start with those possiblities even before buying the volt-ohm meter. As to the spark coil mounted on the left cylinder head, remove its 4-wire plug (lift tab on the left side) and when viewed at the side of the coil pack which has the socket, the pin which is upper right is a common ground point and you would measure between that pin and the other three pins to hopefully find that the resistance is 0.45 to 0.65 ohms on each of the pins. If that checks out then you would need to verify that the wires from the plug to the engine control module are all connected and not shorting to ground, which I can describe next." It appears that you haven't responded to the Allexpert email saying that I had answered. Roland


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