Extracting Fault Codes:
Without ever starting the engine Turn the ignition switch ON, OFF, ON, OFF, ON and observe the CHECK ENGINE LIGHT. The CHECK ENGINE LIGHT should begin to flash a series of codes. The flashes will be separated by short and long pauses. The long pauses separate the "ones" and "tens" positions, and each code from the next. A code 55 will be displayed at the end of the test.

Diagnostic Trouble Codes - 1995 Jeep

11 IGN reference signal. Cam or crank sensors
12 Battery input to PCM disconnected during last 50 key starts.
13 Fault in the map sensor pneumatic circuit.
14 Fault in the map sensor electrical circuit.
15 Fault in the vehicle speed sensor circuit.
17 Engine running too cool.
21 Problem in the oxygen feedback circuit.
22 Fault in the coolant temperature sensor circuit.
23 Air temperature sensor.
24 Intake air temp. sensor voltage high.
25 Fault in the IAC motor drive circuit.
27 Fault in injector driver interface circuit.
33 Fault in air conditioning cutout relay circuit.
34 S/C solenoid circuits.
35 Fault in fan relay circuit.
41 Fault in the charging system or no field current.
42 Fault in the ASD relay driver circuit.
44 Battery Temp Voltage.
46 Battery voltage is too high.
47 Battery voltage is too low.
51 Lean condition is indicated.
52 Rich condition is indicated.
53 Internal problem in module.
54 No cam position signal.
55 Completion of fault code display.
62 Unsuccessful attempt to update EMR mileage.
63 Unsuccessful attempt to write to an EEPROM location by the controller.

 

I tried to retrieve the codes for my 96 zj and nothing happend,nothing on the odometer or flashing of the check engine light

 

Thanks for your reply.
I did the sequence again and got the codes to come up on my odometer. In the order they appeared: 12, 52, 51, and 55. I looked on the list you gave me and I don't know what any of those mean. Could you briefly explain please? Also I noticed the list you gave me was for a 1995 JGC, are they the same for the 1996?

Also, how do I go about reseting the Check Engine Light?

Thanks again.

 

That would appear to be a bad upstream oxygen sensor.

 

Could this be that there is so much dirt covering the engine? Is this a hard part to replace? How do I tell which one is bad?

Thanks

 

Only the upstream one is used for fuel management.

You could unplug it, clean the contacts inside the connector, remove the negative battery cable (to clear the codes) and try again.

Some O2 sensors can be removed easily and some will fight you to the death

 

I noticed that I had three codes, what did the other two mean? Also is it fine to drive around?

Thanks again for your help

 

12 and 55 mean nothing.

 

Should I avoid driving it until I get it fixed?

 

No but your gas mileage go down the toilet.

 

How many sensors are there and where are they located?

Thanks

 

Is the oxygen located on the exhaust pipe before the catalic coverter?

Thanks!

 

10-4 big buddy

 

Are there any special preparations I need to do to the new sensor prior to installing it or just screw the old one out, disconnect the electrical part, and screw in the new one?

Thanks!

 

That’s about it. However, it may be really really hard to remove. They get rusted up in there. Hit the threads with PB-blaster, the day before.

 

I got the sensor out from the exhaust pipe easily, but I cant get the damn connector off. Is there a trick?

 

Hate to bring up an old thread but I have a Code 72 (and 12 and 55 - which I expected).

What does 72 mean?

Is an emissions code aka tighten my gas cap? I came on a day or so after filling up.. :dunno:

 

its got an OBD2 sensor in it and u can go to autozone to get it read it doesnt cost anything and it would bring up trouble codes if anything was wrong with it. i had an output speed sensor problem and it didnt cause my CEL to come on but i had the computer checked just to see and that when i found out about the speed sensor. you can buy one there too and the best one ive seen is like $120 and it even can tell u how your rpm's are when the vehicle is running.

 

Any other ideas?

Isn't exactly convenient or on my way for me to go to Autozone.

 

I tried to retrieve the codes for my 96 zj and nothing happend,nothing on the odometer or flashing of the check engine light

That's because you have a 96. This means OBD-II, you need to have the codes pulled with a scanner, go to AUtoZone or any other parts store they can get the code for you...

from my surgically attached iPad

 

You can key code a '96 or use a scanner. 55 code means it is finished with the coding sequence. A 51/52 could easily be a MAS searching for the right mix. The upstream sensor "1 is in the front downpipe and #2 is after the Cat. If the cat is not functioning it will send the reading to the ECU as the downstream sensor. It does not mean the sensor is bad.
The most important sensors for the ECU which can prevent starting is the CPS, Dist cam position (its the one inside the dist-very common problem) MAS. Always check for the 5v supply when the key is in the on position. Also check the ASD relay. It can be switched with the ac relay for test purposes.

 

I'm having similar issues. 96i6 . First I had no CEL. And it would stall out. Figured something with fuel/air. First I replaced the fuel filter. Cause I got it with 257k miles on it. Change air filter, fluids, plugs,wires when I got it. When it started stalling out the idle would drop but if I kept the rpms up in nuetrul it wouldn't die out. Till finay it just started dying all the time. Took the iac valve out cleaned it and the throttle body. Put both back in. It seemed to work for a couple miles the died almost instantly after starting. Unplugged map/to sensors plugged back in. Finally r CEL popped up. As of right now it backfired and dies sometimes but if I start it and let it warm up as well as revving the engine for awhile it drives fine after. But the codes I'm getting are 12,43,72,45. Hopefully someone can point me in the right direction cause I'm thinking about just pulling the iac,tps, and map sensors and buying new ones. Thanks in advance.

 

1) Don't dig up dead threads, start your own so people will see your problem and not try to solve the OP's issue from 7 years ago.

2) Dirty dozen, step by step, in order, then report back: http://www.jeepforum.com/forum/f13/12-things-you-can-do-when-your-zj-stalls-1407423/