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No power to supply side of fuse in PDC

11K views 2 replies 3 participants last post by  carverman  
#1 ·
I have looked at the diagram until blue in the face. I have no power to the supply side of the fuse for the 02 sensor in the PDC. Any suggestions?:confused:
 
#2 ·
I haven't taken one of those apart, but from experience in dealing with other varieties that had similar problems, here's what I suggest as your next step.

With the battery disconnected, remove the PDC and open up the bottom so that you can see all the wire feeds to the individual fuses (sometimes there are little panels at the top that you can pull out to see the same thing). What I would be looking for with the thing opened up is either a badly corroded connection or a corroded/broken jumper - Chrysler used a lot of jumpers in between various fuse positions as part of the "feed" circuitry and these jumpers can get corroded and break - these problems are sometimes painful to solve. I've had to struggle with some locations of broken jumpers to be able to solder in a replacement. Depending on how easy it is to access that side of the PDC, you can try re-routing that part of the circuit, or get another PDC at an auto salvage yard - this may be the easiest way to go, especially if you're willing to remove it from a junked vehicle yourself.
 
#3 · (Edited)
Power to the O2 heaters or the sensors themselves?

The +12 v power to the O2 heaters is sourced by a 30 amp fuse that
goes through the contacts of the ASD relay.
There is joint connectors in the PDC..one is called Joint connect #2.

Ground for the heaters (02 sensors are 4 wire) is returned back to the
common ground point G103/G105/G107 there.

Sensor ground (the actual sensor itself, not the sensor heater) is sourced
at the PCM Connector C1 pin 4 , I believe.
(I have the pinouts for the 3 PCM connectors, handy).

The signal coming in from the sensors is read at the PCM, connector C1 (upstream) and pin 25 (downstream) .

Yes, there are intermediate connectors/jumpers/splices in the PDC which
make it a bit more difficult to trace.

S= Splice C=connector

Sensor ground is via S101, S103 to the upstream sensor,
and C106, S157,C352,S149, to the downstream sensor , and then C352 and C106
back to C1 on the PCM.

Why they had to go that complicated route is anybody's guess.