Ruzty

My 2000 Vette is not supplying power to my oil temp sensor. I got Code B1542 High Oil Temp short to ground. Hot or cold I get 392 temp reading. Changed temp sensor, connector and inspected wires throughout the engine bay/inside passenger side wire harnesses and still no power. All other gauges work fine. Have yet to pull IPC/Dash panel. If need be how difficult is to rewire the system from the IPC to the sensor? Or am I just missing something obvious. Any replies are appreciated...

Greg_E

Have you tried breaking the connection for the sensor at C102 cavity W and/or C150 cavity P to see if the high temp indication clears? If it does you have a short to ground between the connector and the sensor. It could still be shorted between the IPC and C102 but at least those two connectors should be easier to check.

C102 (20 cavities) Instrument panel harness to forward lamp harness, RH side rear of engine compartment -- Inline Harness Connector End Views in Wiring Systems


C150 (20 cavities) Forward lamp harness to Engine harness, RH side rear of engine compartment, below the battery -- Inline Harness Connector End Views in Wiring Systems

Ruzty

Greg, On the wiring harnesses I don't see C102 or C105 labeled on them when I inspected the wires previously and are they the round connectors? I did pull fuse #19 inside the passenger side floorboard and the oil temp on the IPC displayed Oil Temp, with no temp reading. Thanks for your Time

Greg_E

Yes round connectors. C102 and C150 Wire should be Dark Green/White. There are other Dark Green/White wires in those connectors so make sure you get the correct pin.

If you disconnect pin B from the the oil sensor is the oil temp still maxed out? If there was no short you should see a B1543 Oil temp sensor circuit open code. If its still reading max temp you need to find the short.

If so I would disconnect c102 and check to see if that wire is shorted to ground between the connector and the sensor pin B. The problem could still be in the IPC or somewhere between the IPC and the other half of the C102 connector but at least you can check that much.

I've read some other posts not related to this particular problem, but there have been some problems with the pins on the IPC connector. Just something to keep in mind.

I was reading a post by Bill Curlle and all of the other gauges in the IPC get their signals from the PCM via the serial data buss. Unfortunately the oil temp sensor is not shown on that schematic. I would think that it works the same way but I don't know. IPC senses short in the oil overtemp circuit. IPC sends message to PCM? PCM sends max temp message to the display? To anyone reading this please post if this is correct or not. The schematic posted above would seem to indicate that the IPC posts the message directly to the display. I do not see where the PCM is involved.

When you pulled fuse 19 you are disconnected ignition power to the IPC. There is still battery power to the IPC so you could still see the temp light but anything in the IPC that runs off of ignition voltage is not being powered. This brings up another question. Are you reading normal battery voltage on the DIC? Many posts about bad contacts in the ignition switch causing all sorts of weird problems.

BTW I am by no means an expert on any of this. Just trying to help.

phildo34

Did you ever solve this?? I am having the same exact issue/symptoms.