What does the ditloid 12 p in the r c t mean - Cars & Trucks

Code 12 means that the battery input to the PCM was disconnected within the last 50 key cycles (this is a normal condition).
Code 55 means that you have reached the end of the codes. This is also normal

So if you have a 12, 55 code readout, you basically have no error codes stored.

Here is a link that lists the code sand what they mean.

OBD 1 Codes DodgeForum com

When you flash codes on a 95 trooper..it should flash code 12 pause and flash code 12 two more times...if no other codes flash it means there are no codes stored...code 12 is basically, enter codes, beginning of codes and end of codes.
I just double checked cos 95 models were I thought allrunning the obd 2systems..but production dates after the 8th month are considered next year models..so maybe yours is a late year production. I am going to send a picture and pre odb2 code 12 is a code..hope this helps!

I assume you mean 12 , 23 , & 55 right? If so the 12 means no ignition reference or battery has been disconnected.. (if vehicle not running during test this is OK) 23 mean there is a problem in the IAT circuit (Intake Air Temperature sensor). Could be faulty sensor or poor connection. 55 means end of code string.

Code 12 doesn't need fixed. When you begin to test codes you will get the code 12 but that is just telling you that it is in diagnostic mode, it will flash the code 12 three times, then after that it will flash all stored trouble codes. After all stored trouble codes have been displayed, the ECM will repeat the process( so getting code 12 again means you have reached the end of the stored codes list) If it displays code 12 three times and then displays code 12 again , it means you have no problem codes.

code 12 means it is ok

how do I replace an o2 sensor in a 1997 Jeep Cherokee ?

CODE 12 MEANS BATTERY DISCONNECT.WHAT IT MEAN THE PCM WAS DISCONNECTED WITHIN LAST 50 KEY ON CYCLE. CODE 43 MEANS -CYLINDER MISFIRE.OR IGNITION COIL PRIMARY CIRCUIT.

a code 12 means no G or Ne signal to the ecu im put side for at least 2 seconds that code is ground (G) so it is an open or short to ground on the ECU threw the STA circuit

12 is a battery disconnect within the last 50 start cycles and 55 means the end of the diagnostic cycle.  Basically the computer found nothing wrong. The 12 code may seem incorrect if you haven't disconnected the battery recently, but from my experience the 12 code shows up almost all the time regardless.