1998 Dodge Caravan Service Engine Soon Light

1998 DODGE CARAVAN
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J_BOYD
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Engine Mechanical problem
1998 Dodge Caravan 6 cyl Front Wheel Drive Automatic 208046 Kilometers

Earlier today the Service Engine Soon light came on, I checked for trouble codes and got 12 17 21 55. Allpar shows the codes referring to a possible thermostat problem and a probable oxygen sensor problem. Would it be advisable to change the thermostat and oxygen sensor myself? or is there more going on here than that?
Aug 11, 2009 at 10:54 PM
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BMRFIXIT
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Not a bad or complicated job to do
I would check thermostat 1st and reset code
1st good luck
Aug 12, 2009 at 5:35 AM
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J_BOYD
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Thanks for your reply,

1st, when changing the thermostat do I need to drain and flush the rad system like it says on the box?

2nd, how do I reset code?
Aug 12, 2009 at 11:49 AM
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BMRFIXIT
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You dont have to do it but its recommended and better if you do
disconnecting the battery would reset the PCM and codes
Aug 12, 2009 at 7:46 PM
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J_BOYD
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Ok thanks,

I changed out the thermostat and reset the PCM & codes.

Drove it for a bit and eventually the Service Engine Soon light came back on. This time it only read 12 21 55 so it looks like the 17 code was fixed by replacing the thermostat. However looks like I will need to replace the O2 sensor.

After calling around for pricing for the part I have been told that there can be up to 4 O2 sensors.. Left Bank, Right Bank, Pre-Cat, & Post-Cat. How many O2 sensors does the 98 Caravan have? and which one would this code refer to? don't really want to replace them all but I guess I will if I have to. Also I guess I would have to pick up a repair manual as this doesn't sound like an easy job.
Aug 12, 2009 at 9:23 PM
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BMRFIXIT
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Try and get it scanned as p0000 codes will get a clearer idea which O2 sensor it is
most part stores have an OBDII readers that you can use
Aug 13, 2009 at 5:38 AM
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