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95 Intermittent start up. No check engine light in "on". Code 12? HELP!!?

T

tg22ar

NAXJA Forum User
Location
Elmwood Park, IL
I have a 95 4.0. It runs and drives great, once it starts. When I did the check engine light key test it threw me a code 12 then 55. When I turn the key to fire it up, sometimes the check engine light will not come on. If key is left in the on position, sometimes the check engine light will come on, I hear power come and the fuel pump primes, then fires up perfect. Other times I dont hear a thing, no fuel pump prime, no check engine light with key in on position and it wont start if I try then. Everytime I turn it on, all of my radio presets are gone, clock reads 12:00 like I disconnected the battery but havent. I am a noob when I comes to electronics and wiring. Any help is greatly appreciated. Id rather not bring it to my mechanic and use the $ for upgrades. LOL.
 
Re: 95 Intermittent start up. No check engine light in "on". Code 12? HELP!!?

12 is start code, 55 is end code. both normal.

sounds like a faulty/intermittent ignition switch to me
 
Re: 95 Intermittent start up. No check engine light in "on". Code 12? HELP!!?

It sounds like the IOD fuse may be blown and possibly a bad ignition switch as Digger said.

The code 12 is normal if the battery has been disconnected in the last 50 ignition cycles. Code 55 means end of codes. So basically, the clock reading 12 and the code 12 (without having disconnected the battery in the last 50 cycles) indicate that somehow, you aren't getting power to the IOD (ignition-off draw) circuits, aka the radio and ECU. It running funny/not starting up properly is a symptom of a bad ignition switch and/or IOD circuit not being powered - does it have trouble idling for a few minutes after you start it? That typically happens when the ECU has been left unpowered for a while.

So check the fuses in the PDC under the hood, specifically the one that says IOD or Ignition Off Draw, and make sure your ignition switch is working properly.
 
Re: 95 Intermittent start up. No check engine light in "on". Code 12? HELP!!?

I will check out the PDC and the Ignition Switch when I get home later. Digger - Ok I was unaware of that. thought just the 55 was the end of codes.
kastein - No problems idling after a few minutes. Runs/drives great. Its just this memory/start up issue. Thanks.
Ill let y'all know what happens.
 
Re: 95 Intermittent start up. No check engine light in "on". Code 12? HELP!!?

Checked the PDC. IOD was blown. Replaced it, presets store, clock displays correct time after being shut down. Yay! Going to get an ignition switch tomorrow morn to see if that cures it up.
 
Re: 95 Intermittent start up. No check engine light in "on". Code 12? HELP!!?

Got the new ignition switch in. Symptoms are still there, but only on the first turn of the key to "on".(CEL lights/primes after 3-5 seconds) and hear the fuel pump prime but on the 2nd turn it lights/primes right up and so forth...? And fires as usual. Dafuq? With the old switch it would take a while to light up by the way.(3-10 turns of key, long+short time intervals)
 
Re: 95 Intermittent start up. No check engine light in "on". Code 12? HELP!!?

Doubt it's the ECU... what codes are you getting now?

This is odd, any "custom" wiring from POs under the hood?
 
Re: 95 Intermittent start up. No check engine light in "on". Code 12? HELP!!?

Ok. As soon as I get in it after been sitting all night or for 5 minutes without the key turned, it takes a while for it to get power. Once I hear the pump prime and CEL light up it will prime every time after that. Get out wait another 10 and it takes a while again. There does seem to be some "custom" wiring but for fogs and that. There are a few connectors disconnected on passenger side by pdc. I'll post pics in a few. trying to upload pics...which seems to be a chore
 
Last edited:
Re: 95 Intermittent start up. No check engine light in "on". Code 12? HELP!!?

20130513_110726_zps34e18fab.jpg.html

20130513_110735_zps6bac95b3.jpg.html

20130513_110744_zpse705d231.jpg.html

20130513_111148_zpsc388e5de.jpg.html
 
Re: 95 Intermittent start up. No check engine light in "on". Code 12? HELP!!?

swap the ASD relay with another like relay
 
Re: 95 Intermittent start up. No check engine light in "on". Code 12? HELP!!?

looks like the A/C has been removed.
 
Re: 95 Intermittent start up. No check engine light in "on". Code 12? HELP!!?

Thanks Digger. The A/C is removed. Going to swap out those relays and see what happens.
 
Re: 95 Intermittent start up. No check engine light in "on". Code 12? HELP!!?

the 4 pin connector in the second to last pic is for the cruise
 
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