QuestionQUESTION: Hey, Russel. My name is Ken. Hope you have a spare sec. to read over this problem I'm having with my '02 Dodge Neon ES.... I accidentally plugged the cam sensor connector into the coil pack, and coil pack connector into the cam sensor and then tried to start the engine. After realizing my mistake, I corrected the problem, but the engine would only backfire (out intake and exhaust) when I cranked her. I checked for codes and got 1 relating to the cam sensor and went ahead and replaced it. Unfortunately I get no spark now (code did go away, however). Spark returns when I unplug the cam sensor connector and crank, but it's the same backfiring I got earlier. I checked with a tech. over at my Dodge dealership and he seems to think I may need to replace the PCM, which will probably be costly considering the car has a SKIM feature.
Do you think the tech. is correct that the PCM is to blame? Not sure if there's an (relatively) easy way to test the one in there. I thought about testing the crank position sensor in the off chance that has something to do with this.
ANSWER: It is possible that cross connecting the wiring for the cam sensor and coil pack could could take out the cam sensor portion of the PCM. The PCM is faily fault tolerant in that respect but not bullet-proof. So in that repect the tech you spoke with was right. I believe there is more to this than meets the eye. Could you fill me in as to what repair you were doing that entailed disconnecting these connectors?
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QUESTION: Thanks very much for replying.
I had to unplug the sensors in order to remove the head from the block. The timing belt broke and bent 4 valves. I replaced the damaged valves, lapped all 16, installed new stem seals and then popped the head back on with a new gasket
I just tested the crank sensor recently using directions I found here: http://troubleshootmyvehicle.com/main_index/chrysler/neon_ckp_cmp/ckp_sensor_neo
After following the steps, the conclusion I came to was the sensor appears to not be receiving enough power from the PCM. Specifically, referring to "CKP TEST 2: Verifying Power," voltage I measured between wire #3 and ground was ~2VDC, instead of the ~5-8VDC, it apparently should be.
I did check all fuses in the dash and under the hood, by the way and they were all fine.
ANSWER: Th cam and crank sensors share a common 8v supply from the PCM. If one has low voltage then both should. In which case there is a slight short to ground on that circuit or the is internally damaged. To check for a short to ground on the 8v sully wire, unplug both sensors, unplug the black 40 way PCM connector, clamp one end of the test light to the battery + termanal and probe cavity 44 of the PCM connector. If the test light lights up you have to find the source or the short to ground, if it does not light up, you're looking at a PCM replacement.
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QUESTION: I tested pin 44 I did not get a significant voltage reading (key on or off) on my D.M.M.. I grabbed a PCM from a local junkyard, plugged it in and the motor started right up. Only problem now is, it stalled about 3 seconds later because the car has that SKIS theft prevention system. Dealer wants $100 to re-flash to get it to work with this car. That, of course, doesn't include the cost of a tow to get it there.
From what I've read in order to avoid the trip to a shop, I have to find a PCM, transponder key and antenna circuit (integrated into the ignition lock cylinder) which basically all come from the same vehicle to get it to work. Since the car I'm repairing has an auto transmission, I imagine the PCM must be from a donor car which has that type as well.
Does all this sound right, or do you happen to have a rabbit you can pull out of your hat for me on this one? =)...
AnswerI've been down this road too many times and unfortunatly you will not like the answer. The person you talked to at the dealership, who told you that they could re-flash the controller so it will work, hss no idea what he's talking about. You probably talked to a service writer or parts man, both of whom, for the most part, don't know diddly about how to fix a car, Truth is that once a computer has been assigned to a vehicle, that vehicle and all its components are all it will ever know. The memory area that the information is written to is permenant and cannot be erased unless you're a programmer with the tools and authority to do so. So that being said, you can chase around all the junk yards you want to find what might fix the car, which will not be an easy task, and may not even fix the car but cause even more problems. Remember what I said about the computer knowing what car its in. You should seriously concider going to a dealer having them install and program a new computer at this point.
