1997 Saturn SC2 Could be a bad PCM

1997 SATURN SC2
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KDZEE
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Computer problem
1997 Saturn SC2 4 cyl Front Wheel Drive Manual unknow miles

I had a random misfire code P300 and I changed the Valve cover gasket, spark plugs, and wires... When I reset the Computer, and drive the car for appropriate miles, I get a Inc. readings on the Cat. Monitor, the EGR System, and the 02 sensor..... The guy I bought the car off of was driving it with a bad battery, and keep jump starting it or charging the battery. I suspect this could of damaged the PCM....
May 7, 2010 at 4:27 PM
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SATURNTECH9
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How did u reset the computer?also do u mean ur cat and egr monitors won't set?let me know.
May 8, 2010 at 6:58 PM
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KDZEE
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I used a trouble code reader to reset the computer... Yes the Cat, Egr, and O2 sensor won't reset... But the service Engine soon light returns with the P300 code random misfire....
May 9, 2010 at 5:10 PM
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SATURNTECH9
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https://www.2carpros.com/forum/automotive_pictures/416332_19962000_obd2_drive_cycle015_1.jpg

u can't reset ur monitors by clearing ur codes.the reason that there not ready is because of the bad battery and replacing the battery.I posted the monitor reset procedure for u follow that.then drive the car for atleast 50 miles with out turning the key off.see if ur monitors reset if they do then clear ur codes and we will see if ur code p0300 comes back.and we will look at that code next.let me know what u find.
May 9, 2010 at 5:48 PM
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KDZEE
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I drove the Saturn after following the monitors reset Procedure... Still the same... the Cat, EGR, & O2 read INC.... The car started to misfire, so I cleared the codes, and a new code of 303 is indicated.... I noticed the temp. gauge only reads @ a 1/4 or the first line. Is their a certain temp. for the PCM IS to operate at?
May 11, 2010 at 4:54 PM
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KDZEE
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I saw in "First things to check" if the thermostat is stuck open... or if the car has a thermostat at all.... the PCM will be in a open loop... so I will check this out first...
May 11, 2010 at 5:33 PM
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SATURNTECH9
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[quote:c3d88f358b="Kdzee"]I drove the Saturn after following the monitors reset Procedure... Still the same... the Cat, EGR, & O2 read INC.... The car started to misfire, so I cleared the codes, and a new code of 303 is indicated.... I noticed the temp. gauge only reads @ a 1/4 or the first line. Is their a certain temp. for the PCM IS to operate at?[/quote:c3d88f358b]
so u did the drive cycle and then drove it 50 miles without turning the key off?ur car only gets to a 1/4 on the gauge what temp is it outside when this happens?it should get to half way and above that.unless u have a bad coolant temp sensor showing cooler then it really is on the gauge or a bad thermostate.try sitting in park and holding ur rpms up to like 2,000 rpms for a few mins it should go above 1/4 see if u can get it up above the 1/2 way mark to 3/4 mark see if the fan comes on.let me know what happens.we need to get the car hotter then 1/4 so we can reset everything.
May 11, 2010 at 5:41 PM