i have a 1999 automatic neon.. last month i took my car in to change the timing belt and water pump (145k + miles).. they said my CE light went on after the test drove and said i might have a bad o2 sensor, but because they got the CE light to turn off i shouldn't worry unless it comes back on.. well jus the other day the CE light went back on.. now my car is having hard starts, rough idling, and some stalling.. is the problem still my o2 sensors?? i tried doing the "on, off, on, off, on" thing and it gave me code 12, 32, and 55.. what do these codes mean and how do i fix them? also where can i find the o2 sensor on my car? they want to charge me a grip to change the o2 sensor, but i figure if i can change it myself, better for me..

mahalo (thank you) for your replies

 

12= the battery has recently been disconnected(this means nothing, ignore it)
32= this is your problem, call the dealerships service department and ask them what this code is(fix this)
55= the computers self check is complete(self explanitory)

There are 2 O2 sensors on your Neon. The 1st one is the important one that tells the computer the air/fuel ratio, it is located on the exhaust manifold below the air box against the firewall. The 2nd is after the catalytic converter and all it does is tell the computer(PCM) if the catalytic converter is bad, and if it is bad it tells the PCM to turn on the check engine light.

 

Don't remember off the top what 32 is but a bad O2 sensor is not causing hard starts and poor idling. The O2 has nothing to do with starting or cold idling, I would guess somebody at the "repair" shop made a bobo. I would go to the nearest dealer soon. I am guessing you have 2.0 SOHC engine, that engine will not tolerate cam timing errors-not FREEWHEELING. After doing timing belt work the pcm cam timing needs to be rest, it keeps track of belt stretch to warn you if there is a problem.