Chrysler Repair: fault codes:0106,0122,0405, volt power supply, throttle position sensor

Question
QUESTION: Hi Roland,
I have a 99 Concorde with a2.7. Last night my wife was driving and the check engine light came on and then a few seconds later the car quit. When we would try to restart it would fire but not stay running. I did the fault code check and came up with 5 codes. P1684, P0122, P0106 P1496, P0405.
Could you tell me what all these mean and if they are related to car not starting? Thanks for your help.

ANSWER: Hi Gene,
The 106,122,405 codes are all related to sensors that are needed for the engine to start and run. They have one common connection: they all require a 5 volt power supply that comes from the engine computer. I would wonder if there is a short to ground of that wire such that none of the sensors are getting that voltage. It has a violet/white color code and originates at pin 61 of one of the two sockets of the controller (the one whose plug show pins 41-80. You could pull that plug and after noting which pin is 61 test the socket to see if it shows 5V with the ignition switch in the run position (but it is possible that by pulling the plug it could kill that voltage source, so this is not a definitive test of the controller).
Better would be to measure the resistance of the plug-side pin 61 as compared to ground to see if it reads close to 0 ohms (a short) and if so then we have to look for the component or location on a wire that is causing the short. The wire goes to:
the egr valve, the throttle position sensor, the manifold pressure sensor, the a/c pressure sensor, so those are the items you could disconnect one-at-a-time to see if that would cause the short reading to jump up above 0 ohm significantly and which therefor would suggest that item was shorted. Other than that I would inspect the harness to each of those devices to locate a spot where the insulation has melted and allowed two wires in the harness to touch oneanother (the other wire presumably being a grounded wire for other purposes).
The other codes are not relevant to the no start. The 1684 says the battery was disconnected in the past 50-100 key on-off cycles from the controller (either at the battery or the controller), and the other code is about the leak detection for gas vapors having a slight leak.
Roland

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

QUESTION: Hi Roland,
It's me again. Is it possible the eng. computer is bad? My neighbor had a code reader he hooked up. It showed all the codes I mentioned but he said the computer was not responding toto other things on his machine. So he thinksits the computer.
Also we did get the car to start but it only idles sort of.
When we did have it running for a while the oil light stayed on but it was full of oil and it seem to have oil pressure cause it wasn't knocking or rattling. Which also led my neighbor to think its in the computer. Would appreciate your thoughts.
         Gene

Answer
Hi Gene,
No, the computer also has codes for its malfunction so I doubt that is the issue. It could be that the 5 volt output of the computer is bad, but before concluding that is the case I would do the measurement that I suggested to see if the output instead is being shorted to ground and thus causing the codes you got. Then try erasing the codes (unplug the battery for a minute or so), disconnect all the sensors and try to start the engine again and see if the same codes occur or not. The oil pressure light will naturally come on if the engine is not idling at its design basis speed so that is not surprising.
The three codes are too consistent with oneanother to be a glitch in the computer, until proven otherwise by troubleshooting as I described in my first answer.
Roland