You are here:

Chrysler/1999 Chrysler 3.5 300M


QUESTION: All was fine, battery light came on panel, 10 minutes the car just died,, got jump started made it home, and car died.. battery was dead, had both alternator and battery checked, both OK.  found OSS fuse on distribution fuse panel blowed, put another one, blows as soon as starts.. no charging to battery.. found that this fuse also powers, OS sensors, EGR, etc.. disconnected all of them, put new fuse, charging OK, connected all 4 sensors, still OK,, when I connected the EGR, the fuse blows, disconnected and put new fuse, all OK.  5Vdc going to EGR pins (2-3), is it stuck, hard to take off, can I run the car with the EGR not connected, someone told me to use Seafoam to clean the intake and valves related to fuel mixture.. need ur help...

Schematic diagram
Schematic diagram  
ANSWER: Hi Paplo, your PCM must be judged first using DRB III set to insure free of dysfunction , if succeeds then You have stucked EGR and/ or partially burned its coil, or an intermitten  short  in its wiring, the EGR is powered by ASD relay thought the burned fuse, the generator induction coils is powered also by ASD relay, the car PCM is engaging  the EGR not all the time but some time and for a very short period, and usually while the engine is hot, the EGR valve function is to bypass the exhaust gases to intake manifold as PCM order based on the received data from the O2 sensor
Now let me tell what is going on:
When the engine is cold most likely the stucked open EGR valve closes, or the intermitten short goes off , so the car run fine, after heating up the PCM engages the EGR coil meaning the power is pasing through the wiring, at this moment the short is happen causing blow the fuse, this short is engaging the PCM to cut the earthing of ASD relay which cut the power of ingectors, fuel pump and the plug coils as a safety wise, engine is dead now.
The same will happen if the EGR will stucks open, when the PCM engages it, it doesn't close after cut off the power, the PCM can read this situation wich considered abnormal, so it will cut the ASD causing shut off engine
Also, if the EGR coil is burned the current is very hight when the power is supplied, the PCM can read this and shut down evry thing,
Not all the cars have an EGR, so you can unplug it when the engine is cold over night, but because the PCM is remembering it you will receive check engine light in cluster, also we don't know if you have a wiring short and/or stuck EGR, SO do the followings :
1- check first the wiring to the EGR insuring no short or repair
2- install a new one if you need to restore the car
3- if you will cancel it install a piece of plate between the base of the EGR and exhaust as a plug to isolate it completely, cut this plate from stainlessteel 1 mm
    Thikness with the same shape and screw holes of existing gasket
4- using the OBD II scan tool reprogram the PCM to forget the EGR, or let the check engine lights and forget abou it,
I attached the schematic diagram of your car may help you,, if it's not clear send me your email to resend more clear, for the cleaning of intake valves just add a good injector cleaner for fuel tank, it will clean the intake valves too,,

---------- FOLLOW-UP ----------

QUESTION: You mention, when engine cold, egr closes,, if stuck how does it close or opens when engine is hot. I see what the ASD relay controls, but when the fuse blows the car keeps running until the battery runs out, because it affects the charging circuit that goes through that fuse (T 20 Amp), the ASD is not cutting out when the fuse blows, because other fuses control the injectors, fuel pump, etc... right now with the egr disconnected, car runs fine.. do not know if the egr is close or open,, how can I tell.. it is hard to take out and expensive ($200)... Note:  the valve should be close if not connected, engine hot or cold,,right.. leave it in as a plug and re-program PCM like you mention to clear cluster...

I wached the stuck open EGR swich to close when cold many time, but it's not the matter now
Since the fuse blowe out just plug the EGR,  and the engine still run normaly till pattery run out, so your internal coils of EGR are shorted to ground, and your EGR is sure closed (engine run fine), and that blowen fuse  sure feeds the power to generator induction coils (no charging, battery drained)
Chrysler mostly feeds the generator from the same fuse of fuel engector and coil plugs, but some time from the EGR fuse and this is your case.
It's simple, just unplug the EGR, replce the fuse, run the engine and check charging if okay keep the EGR as plug and forget about the cluster light or use the OBD II scan tool to delete the EGR out of PCM memory to shut of the light, or replace the EGR,
The EGR is safety invironmental wise, it recycle the exhaust when CO is present to re burn it to CO2, the CO is prodused in misfire cases, wrong octain fuel, or engine mecanical problem,
Note may your engine failed in smog check without the EGR,
At last i advice to replase the ASD relay, because the repeated short created an internal bad contact, and this will cause missfire specilly with high load and strong acceleration,
Let me know


All Answers

Answers by Expert:

Ask Experts


Essam Seddik


Gasoline cars: all types of engines electronic controls, electric diagrams and wiring, engines mechanical problems, accessories (security, audio video systems, lighting control etc...,) I have no knowledge on big trucks.


30 years, I have a car service for American and Korean cars.

Bachelor degree of mechatronic ,

©2016 All rights reserved.