Expert: Roland Finston - 8/31/2011

Question
My son's 1999 Chrysler Concorde 3.2L will start, but runs badly.  Black smoke from the exhaust, stalls when driving...weak intermittent power from engine.  I did the "key dance" and came up with the following codes:

P1684  Battery has been disconnected in last 50 starts
P0203  Injector Circuit Malfunction, No 3
P0122  TP Sensor Voltage Low
P0108  MAP Sensor Voltage too high
P1496  5 Volt Output too low
P0406  EGR Position Sensor Voltage too high

I also noticed that the Temperature Gauge in the car stayed on cold even though the engine had warmed up (I had to limp it home to troubleshoot it), though it didn't give a code for the Temp Gauge.

It seems to me that there could be a common fault, but I'm just not sure where to start.  Could it be as simple as a faulty Temp Sensor?

Answer
Hi Marty,
The common fault in this situation appears to be the 5 volt power supply which comes out of pin 61 of the pcm on a violet/white wire, then goes to a splice on the left inner fender where it splits to power all the sensors which give the codes that you found, also on violet/white wires. I would try disconnecting all the listed sensors and meaduring the voltage on that wire at each of the plugs involved. Depending upon what you find it could either be short of one of the several violet/white wires or a faulty sensor that is affecting the voltage on the common supply wire. You could reconnect each sensor one at a time and check for any malvoltage at the other sensors plugs as a means of checking the sensors' behavior.  The injector circuit on cyl 3 is likely a separate issue.
Roland
PS Sorry for the delay but I just found your question in the 'pool' to which it had been referred by Kevin.