QuestionQUESTION: Hi Roland
Thank you so much for responding - this is only my second attempt on this site. I am not sure where to go to rate your previous answer, so I am not sure if you will remember this.
ANyway - my mechanic did all the things you suggested and we are now in a REAL confused state. He had a friend come over with a diagnostic scanner. Once they hooked up the scanner - no codes came up AND GET THIS the engine would turn over and run perfectly. The clicking has been resolved. (my mechanic already new your explanation)
HOWEVER, as soon as the scanner is unplugged from the diagnostic plug on the vehicle the engine shuts off. Neither my mechanic or his scanner friend OR anyone in TN that we have spoken to has ever heard of such an issue. We are now trying to determine where to find a wiring diagram for that diagnostic plug so he can trace those to see where they go and HOPEFULLY find where the problem is. My biggest fear is that the PCM is fried. We are HOPING that is not the case, since the scanner seems to create the 'missing loop' in the electrical short?? I am not sure if I am saying that right.... CAN YOU PLEASE PLEASE PLEASE help on this or give an alternative solution? I have no other means or money to get another computer on that van right now.
Thanks SOOOOO Much, again for your time
Morgan
ANSWER: Question: I have a 1999 Chrysler Town and COuntry 3.8L van. The engine suddenly shutoff on me yesterday. There is a clicking sound and vibration coming from beneath the EATX auto shutdown relay fuse. When we wiggled the OTHER Auto shutdown relay fuse engine started briefly then quit. I put in new rely fuses at both the EATX slot and Auto Shutdown spot. What exactly is the EATX rely for anyway? I am trying to do research for my mechanic - I am owner THANKS
Answer: Hi Morgan,
I need to clarify that your use of the term 'fuse' is confusing me. The clicking sounds are coming from the relays themselves, I believe as they are actually electically operated switches, not fuses. The fuses that involve the circuits of which you speak are # 15 for the etax and # 17 for the engine which are involved with their respective relays to power those relays. The fuses are silent, they either conduct or they are blown (open). The fuses I listed are on the other side of the box from the relays.
That being said, the relays will click (opening or closing) under the control of the computers which look at the varius inputs from sensors and decide whether the circuit in question should be switched 'on' or not. The etax is the acronym for electronic transaxle, basically the transmission/differential unit that drives the two half axles.
Both relays have to be closed for the engine to start and for the transmission to transmit power to the wheels (in anything other than 2nd gear, which is the fallback function of the etax when the relay is open due to a detected problem seen by the transmission computer...that default condition when it will only run in 2nd gear is called 'limp-in mode').
The appropriate action now would be to find out what problem (fault) the computers are seeing which is causing them to click open rather than stay closed. If the relays are actually vibrating, that typically is caused by the battery voltage being compromised to such a low level that the power to operate the relay switch is not sufficient to keep it closed, so it clicks 'open' and then the relay tries again to close, etc., etc. If that were the present situation, I would try to charge the battery with a plug-in charger, or jump a known good battery to your van's battery to sustain a high enough voltage that the relays won't cycle that way. It also could be a short circuit that is draining the battery voltage down so if jumping doesn't help, that would be the likely reason.
There may be an underlying problem which a fault code readout would reveal. There is a self-diagnostic capability built-in to the computers. Code numbers can often be found by using the ignition switch: turn the key:"on-off-on-off-on and leave on", doing that in 5 seconds or less elapsed time. Then watch the odometer window of the cluster to see if the mileage reading changes to show 4-digit numbers, preceded by a P, which would be the fault codes. Tell me what those are and we can go on from there. However with all the clicking going on, this may be impaired. So try to get the battery voltage raised by the jumping or re-charging of your vehicle's battery, and also try to do the code readout.
Roland
Hi Morgan,
I pasted in your earlier q and a above.
The data link connector has 16 pins of which 8 are used. 5 of the 8 (3,6,7,11,14) are varius digital communication wires to either the engine or transmission or both computers. I can't see how plugging in the reader would solve a problem involving those computer lines. Without having been there I can't be sure whether the scanner had any other wires/ground clamps or was the only connection via the single 16-pin plug? If it was a pure connection via the 16-pin plug and it had no built-in batteries and no independent ground wires to the vehicle, then my only explanation is that the scanner provided a ground connection that is open in your vehicle.
The ground on pin 4 is a common ground for many circuits of the vehicle on the left instrument panel support under the dash. That one is probably ok, but check it.
The ground on pin 5 is one that is attached to the - post of the battery (via the thinnest of three wires on theat clamp so you might want to check that it is connected to that clamp.
The last wire is a 12V ignition off draw supply that powers up the scanner (unless it has its own battery?) so if the scanner does have its own battery then it may be that the supply is compromised and the scanner is fixing that problem. That supply comes out of fuse 28 in the box that is under the hood and operates many things that are needed even when the van is not in use.
It is not obvious to me why the scanner solves your problem, but those are the wires and their purposes.
Roland
PS Please let me know what you learn, it is very interesting. If you want to rate me, look for the tab labelled 'thank/rate the expert'.
---------- FOLLOW-UP ----------
QUESTION: THANKS - I JUST READ YOUR RECENT ANSWER TO MY MECHANIC - HE SAID HOW DO WE DETERMINE WHAT FUSE IS NUMBER 28? THEY ARE NOT NUMBERED IN HIS HAYNES REPAIR BOOK NOR ARE THEY NUMBERED ON THE BACK OF THE PANEL??
tHANKS, Roland!!!
Morgan
ANSWER: 28 is the one at the very back edge of the box that is under the hood.
I also would direct his attention to the ptc #1 in the bottom row (left end) of the box under the dash whic I just menitioned in a PPS to my last answer.
---------- FOLLOW-UP ----------
QUESTION: Roland,
Brian, the mechanic just tested the #1 position fuse (you mention above as 'ptc #1')in the bottom row (left end) under the dash. It is labeled "pnl ilum" for that position described - ANYWAY...he pulled that position fuse and tested that it is hot when lights are on - it controls the panel lights. We do not find a 'ptc' designation in that panel area.
(I DID NOT GET YOUR "PPS" YOU MENTION ABOVE? DOES IT HAVE MORE DETAIL? COULD YOU RESEND?)
The auto shutdown rely continues to click everytime key is turned.
He also tested the #28 fuse position you describe to be the 10amp off by itself going to computer memory....that tested hot. He has tested all of the fuses under the hood and they are hot except for airbags - but airbags do test hot when key is on.
NOW WHAT??? What would you suggest at this point???
HOPE YOU ARE STILL THERE, Roland!!!1
Regards,
Morgan;-)
AnswerOoops, the PTC #1 is actually higher up in the underdash box, just below the multi-wire plugs, at the very left end of 10 sockets, 5 of which are in use. I mis-remembered that the ptc are up there and the regular fuses are in the bottom row. Sorry for misleading you two. So do check that PTC.
The PPS is a 'revision' of my answer in the other 'string' of q and a we have going here. I think you read it:
"PPS:In light of the clicking relay/fuses that you began this dialog over, I would believe that the issue could be the ignition switch or possibly the positive temperature coefficient device #1 in the bottom row of the fuse box under the dash that may be opening and closing spontaneously due to either a compromised function or some other extaneous 'draw' on its circuit"
As to what to do now: maybe you can re-state what are the current issues:
Does the starter motor crank?
If so, does the engine start?
When you first turn the key to the run position (but not to start) do you hear the fuel pump run for a second and then does it stop and also the ASD relay will open?
I have lost track of what is happening. How about the fact of whether or not the code reader is plugged in. Is that still happening?
The random clicking of the two relays (ASD and ETAX) that was going on last week in no longer an issue? and if so, do you know what solved that?
Roland
Does the starter motor crank? ANSWER TO THIS IS YESIf so, does the engine start? ANSWER TO THIS IS NOWhen you first turn the key to the run position (but not to start) do you hear the fuel pump run for a second and then does it stop? ANSWER TO THIS IS YESASD relay will open? ANSWER TO THIS IS YESIF code reader is plugged in - CAR STARTS RIGHT UP STILL - UNPLUG CODE READER, IT WILL CRANK BUT WILL NOT START UP. The random clicking of the two relays (ASD and ETAX) ANSWER TO THIS IS YES ONLY IF ATTEMPT IS MADE TO START CAR WITHOUT CODE READER PLUGGED IN.
Hi Morgan,
You didn't mention whether the code reader being used ONLY is attached via the 16-pin plug. If so, then I am at a loss that you have no fault codes of any kind. I would have expected some sort of a 'communication failure'. If the reader has an accessory grounding lead and that was used then that would make me wonder about the quality of those two ground connection on the 16-pin plug that I mentioned earlier.
Roland
