Got a Code

after driving for a while, a stopped for about 5 minutes then started again, got no oil pressure on the gauge, did key thing, got codes 12, 42, 55.

12 and 55 are fine but I have no idea what 42 means

from hesco: http://www.hesco.us/obd.html

42 (1)
ASD relay control circuit
An open or shorted condition detected in the auto shut down relay circuit.

or

No ASD voltage sense
No ASD voltage sensed at PCM.

I was expecting something about oil pressure, but got this gibberish :gee:

Can someone tell me what this means?

'97 4.0, auto, 125,000mi


thanks,

B

B, I'd suspect a sticking ASD relay. That's the one that keeps power on the IAC/idle control for about 6 seconds after shut-down. This sets the IAC for the proceeding start-up.

I have no idea why this would affect the oil pressure gauge.......?

EDIT: There's one other possibility: That might be an old code, and the trouble is actually in the oil pressue sender wire/plug. Try un-plugging the sender, and re-plugging it. If it's loose, the gauge wouldn't work, nor would you get a code for it.

Thanks for the quick reply.

where do I start looking for this relay?

My oil pressure has been weird for a while. I get about 40 after a cold start, then it normally drops down to between 10-20 on the gauge. It has been close to zero before, but the light never came on before- this time, I started it up, saw the "check gauges" light on, and saw I had no oil pressure while idleing smoothly at about 800RPM. I shut it off as fast as I could. two minutes later I restarted it, got about 25on the oil gauge at idle, no warning lights, and drove the mile or so home.

code can't be more than a few days old, had emissions test last week, no codes then.

Runnin'OnEmpty said:

B, I'd suspect a sticking ASD relay. That's the one that keeps power on the IAC/idle control for about 6 seconds after shut-down. This sets the IAC for the proceeding start-up.

I have no idea why this would affect the oil pressure gauge.......?

EDIT: There's one other possibility: That might be an old code, and the trouble is actually in the oil pressue sender wire/plug. Try un-plugging the sender, and re-plugging it. If it's loose, the gauge wouldn't work, nor would you get a code for it.

Click to expand...

Low oil pressure will cause the ECU to shut your engine down by opening the ASD relay so there is a connection.

unplugged oil pressure sender connection, blew on it, plugged back in. oil pressure at start read 42, after ten minutes or so, dropped to around 15 on the gauge. - fairly normal for the last 2 years. code gone. , engine sounds normal to me.


I guess the main question I need to answer is whether I'm actually losing oil pressure(I don't think so), or if it's an electrical problem. advice on narrowing down the problem appreciatied.


Thank you

B

Those oil pressure sending units have been known to be fickle when they get old. I'd guess its seen better days