Question about 1999 Chevrolet Malibu
I have a 99 malibu with a 3.1l that wont set the H0S monitor nor the evap, cat, secondary air, egr. did the drive cycle provided by gm 4 different times and nothing. the car goes into closed loop and idles smoothly. it reaches a temp around 217 deg. but still wont set. looking for any suggestion. also did check function of o2 sensors and found no fault.
You might start considering the PROM as these values and other parameters could be incorrect within the chip programming especially with Banks add ons.Another item,EGR could be agressive and delivering too much flow causing uncontrollable lean mixtures that put you into open loop.Check all other outboard sensors such as Temp-MAP which could take your system into open loop as well as o2's which you are aware of.It is possible for o2's to be giving false values...good luck
Posted on Jul 01, 2009
No this will not. Computer has a keep alive . Evap and a.i.r. run on different schedules then other monitors.Usually EVAP is gas tank related.Have some smoke system to see if there are any leaks. In NY you can pass with monitor not running for that year truck
Posted on Feb 08, 2010
Testimonial: "thank you for your reply it was helpful to know the pmc has to be kept alive."
evap vent valve if you have a scanner with function test go to evap vent valve turn it on and off should hear a clicking noise
Posted on Mar 17, 2010
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