Well, I have the dreaded engine control fuse blowing problem. I have searched but I have not come across the info that I am looking for.
I have the factory service manuals for my Cherokee.
What I have done;
-Pulled fuel pump relay, fuse blowing stopped.
-Pulled fuel pump module, tested fuel pump and it works fine.
-With a Fluke 112, I checked ohms to ground from connector of PDC for fuel pump relay that goes to fuel pump wiring and get 4 ohm reading (almost a dead short). I then switched to the amp reading mode in the 112 and blew the 10 amp internal fuse in the meter by reading from the 12v connector to the fuel pump wiring connector in the fuel pump relay socket.
-Disconnected main connector inside left kick panel, disconnecting all rear body wiring, including fuel pump wiring. Still get 4 ohms in PDC to ground.
-O2 sensor is brand new Bosch, only about an hour of engine run time on it. O2 sensor power is on fuel pump power wiring. Disconnected it from harness and now I lost the 4 ohm to ground.
(I have actually done much more diagnostics but I am just keeping this short for brevity)
Question is, is the reading for the O2 sensor heater element normally approx 3-4 ohms or is this my short that is blowing my engine control fuse?
I have the factory service manuals for my Cherokee.
What I have done;
-Pulled fuel pump relay, fuse blowing stopped.
-Pulled fuel pump module, tested fuel pump and it works fine.
-With a Fluke 112, I checked ohms to ground from connector of PDC for fuel pump relay that goes to fuel pump wiring and get 4 ohm reading (almost a dead short). I then switched to the amp reading mode in the 112 and blew the 10 amp internal fuse in the meter by reading from the 12v connector to the fuel pump wiring connector in the fuel pump relay socket.
-Disconnected main connector inside left kick panel, disconnecting all rear body wiring, including fuel pump wiring. Still get 4 ohms in PDC to ground.
-O2 sensor is brand new Bosch, only about an hour of engine run time on it. O2 sensor power is on fuel pump power wiring. Disconnected it from harness and now I lost the 4 ohm to ground.
(I have actually done much more diagnostics but I am just keeping this short for brevity)
Question is, is the reading for the O2 sensor heater element normally approx 3-4 ohms or is this my short that is blowing my engine control fuse?
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