P0403: '00 lh 3.5l

QuestionEdit

QUESTION: Hello, (again) Roland, Just a status update about the LHS problem. Found through " TRIAL BY FIRE " that the LHS had a burned out EGR control solenoid, due to the fact that it has battery power on it at all times, found this out through Chilton wire schematic, a test light, and lots of coffee/no sleep. I need the location of fuse "T", I assume this is in underhood fuse box??? 20 amp fuse, part of EGR solenoid control circuit( orange w/blue tracer ), I pulled all 4 20amp regular fuses out one by one,test light stayed on (backprobed from EGR connector while plugged into Valve assembly at Grey w/ yellow tracer, and have power even with key out of ignition), also noted that BATTERY KEEPS GOING DEAD (IMAGINE THAT). Would it be safe to say PCM internal, or Shorted wire in harness? Thanks for the help again! Frank

ANSWER: Hi Frank, T is the outboard-most 20 amp in the row of 6. The egr pin 6 is directly connected to that fuse so it will have power up all the time. The gray/yellow from pin 4 to pin 40 is what causes current to flow when the pcm grounds pin 40. So verify that pin 40 either shows 12V (or 0v when the key is off or on but not running, I can't be certain which) but it any case pin 40 should not show a short to ground with the key off using an ohm-meter. It should be grounded only when the vehicle is running at a constant speed. It could be that the gray/yellow wire itself is shorted to ground (or the pcm 40 socket is shorted to ground internally due to a bad pcm but I doubt) if indeed the egr solenoid is toast. So verify the above to see where you stand. Please 'rate' my answer, once again, and consider another 'nomination'. Thanks, so much Roland

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QUESTION: ok, Roland here goes the latest: p0403, found that test light will go out when engine running ( pin 4, grey/yellow )and has 12 volts when engine NOT running. Checked list of possible causes, found sensor ground ( pin 43,C2 to pin 3-OK,)solenoid power circuit open( 5 volts from 61,C2 to pin 2, EGR solenoid has 5 volts when key on, turns off when key off.), and solenoid control circuit is open, shorted to ground, or short to voltage. I found that power is on pin 34,C1 when key is turned on, run for test, and when turned off, power will stay on longer than 5 min, or unless I disconnect PCM. Any Ideas? Frank ( I will nominate you for head of Chrysler Engineering if we get this thing fixed! )

AnswerEdit

Hi Frank, I suspect that code may have 'set' when/if you turned the key to run with the plug removed from the egr as it calls out the egr solenoid control circuit open or shorted. Try disconnecting the battery to erase prior codes, then reconnect after a minute which should get rid of the 0403 (but you may now find a 1684 (battery disconnected recently) in its place but when you start and run the engine with the egr plugged in I suspect that the 0403 will not reappear. If that is the case, then I wonder if the egr is OK and maybe you are focusing on the wrong cause. The power on pin 34 (something more than 0 but less than 5v) is what you would expect because it is 'looking' at 5v coming out of pin 61/plug pin 2 after going through the internal egr variable resistance of the sensor position signal; and I would not be surprised for it to 'hold' for a few minutes after turning off the engine by dint of it being powered out of a pcm circuit which probably has some voltage/charge on a capacitor that drains off as time goes by. How about going back to the earlier q and a's to see what other things I suggested haven't been checked out? Did you find the source of the whistle, did you check all around the perimeter of the intake manifold for leaks? A massive leak would be a cause for the engine power behavior you described originally. If those don't bring forth results then maybe this is beyond our ability. Thanks for the kind remarks...an Allexpert 'volunteer of the month' nomination will suffice! and which you can offer with each and every answer. Roland