496HO alarm
 

Hey all. I can't find my owner's manual and am hoping someone can help with a 496HO problem. When I turn my key slighly to the right, I get the standard three beeps and then silence. When I then turn further, to start the engine, the engine turns over but I get continuous intermittent beeps until the engine fires up. Typically it happens only during cold starts - when the engine is warm, it usually fires up without the alarm going off. The engine definitely takes longer to fire up now during cold starts that it used to. I've checked all the fluids, including the oil, and all are at proper levels. Any ideas as to the problem? It is taking longer and longer for the engine to fire up and I'm afraid there is a problem that is getting worse (although the engine runs flawlessly once she's warm). Thanks in advance for any help.

Re: 496HO alarm
 

I would say check your MAT sensor. We had the same issue a month ago and that it what it was. Basically, the ECM thinks the air temp is cooler or hotter than it actually is, thus changing the fuel, spark and air ratio hence the trouble starting. Hope this helps.

Re: 496HO alarm
 

MC - Thanks alot for the help - I'll look into that. Any otherideas out there?

Re: 496HO alarm
 

A scan tool would sure be of help in this situation. But if I were to guess, I would say the alarm you are getting is a Cam Sensor fault because it can only be set while cranking (unlike other Fault Codes), and will cause slow/difficult starting.

You can check the Cam Sensor resistance - should be "A" to "B" 24.04 mohms - "B" to "C" 24.5 mohms, at 70 degrees F.

Dave