93 ZJ Trouble Codes

12 - Direct battery input to PCM was disconnected within the last 50 Key-on cycles.

45 - Overdrive solenoid - open or shorted condition detected in overdrive solenoid circuit.

51 - A lean air/fuel mixture has been indicated by an abnormally rich correction factor. (O2 sensor)

17 - Engine did not reach operating temperature within acceptable limits. Engine does not reach 20 degrees F. within 5 minutes with a vehicle speed signal.

I pretty much know the first two, but I'm not sure of 51 and 17... Is 51 an indication that my O2 sensor is bad? And what does 17 mean? What should I check and replace?

 

it does NOT say the sensor is bad, the sensor is a messenger - remember don't shoot the messenger?
that being said we diagnose and that will confirm if sensor is operating OK.
check for Vacuum leaks, fuel pressure.


And the 17 first look at the thermostat - dumb asses like to use the wrong ones.... it calls for 195°F. don't get a cheap T'stat. As I say dem puters be smart.

The OD issue is likely a wiring issue - do you have wiring diagrams?



I will try to confirm codes as some sources are off from OEM.