mhildebrand Posted September 11, 2011 Report Share Posted September 11, 2011 My cutlass has had a rough idle for a few months, and today replaced the IACV. After doing so, the MIL came on and read MAF sensor low frequency. I had no power to MAF, and found the ECM IGN fuse was blown, replaced and car ran fine. Unhooked battery to clear code, and it returned instantly. Drove car about 20 miles and MIL went off. Then 5 miles later it came back on, running like shit. Checked fuse and its blown again. I know this fuse runs the EVAP as well which had no voltage. After replacing fuse, I had 12 volts on these lines, which I thought should only be 5 volts. So I need input. I know it could be a short on this wire, which is pink, or it could be a bad computer. Anyone had experience with this in the past and know the best stuff to check out first? I have to go back to college tomorrow, and would love to have this solved before I drive 2 hours to get back. Thanks in advanced guys. Quote Link to comment Share on other sites More sharing options...
ron350 Posted September 11, 2011 Report Share Posted September 11, 2011 According to the service manual that fuse supplies 12 volts to: PCM #2 fan relay EGR valve MAF O2 sensor heater #1 and #2 EVAP purge solenoid EVAP vacuum switch The first thing I would do is put back any parts I replaced and see what happens. Quote Link to comment Share on other sites More sharing options...
mhildebrand Posted September 11, 2011 Author Report Share Posted September 11, 2011 I know exactly what is run with that fuse.. I ohmed wires today and found that the pink wire is grounded, but only when plugged into the PCM. Quote Link to comment Share on other sites More sharing options...
thikstik Posted September 12, 2011 Report Share Posted September 12, 2011 Is the pink wire the wire which is the common 5v out to all these components and its showingt 12v, not 5v? If so, it would seem the ecm is supplying too much voltage out to that common wire. And when a circuit is activated, (immediate obviously) too much current blows a fuse. I guess im saying, it seems there shouldnt be 12v there anytime regardess of an open or short. If so, sounds ecm..ish. Quote Link to comment Share on other sites More sharing options...
mhildebrand Posted September 12, 2011 Author Report Share Posted September 12, 2011 I thought along those same lines, but the fuse doesnt blow imediately. it took around 20 min of driving before it will.. The PCM pin that runs the pink wire is labeled Power(ignition). So im not sure if its supposed to have 12v on it or not. I thought it whould only be 5. but at the same time, the yellow return wire to the PCM has 5v on it. Quote Link to comment Share on other sites More sharing options...
mhildebrand Posted November 30, 2011 Author Report Share Posted November 30, 2011 I forgot about this post and got it fixed. After tracing all of the wires, i found the wires running to the lower O2 sensor had come out of the retaining clip and had been riding on the exhaust, causing the power wire to ground to the exhaust. i repaired the wire and got it back into the clip, and the rough idle and MIL are both fixed. Quote Link to comment Share on other sites More sharing options...
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