I probably should have started on 'technical/troubleshooting' but started with 'engines/exhaust':
On this category since it's 'engines' and 'exhaust' which relate to the topic... After watching the 'check engine' light go on and off periodically for a few months, I finally went to Auto Zone to have the p-codes checked, the guy didn't know where to plug it in, usually under the dash he says. So where does it hide? Thanks!

 

see other post..

 

Finally got to Auto Zone, got 2 codes: P0335: Definition: Crankshaft position sensor condition. Explanation: Crankshaft position sensor signal is monitored for faults. Probable cause: Crank sensor defective; Check connector and wiring to sensor; Check trigger wheel for damage. Code P0410: Definition: Secondary air injection system fault. Explanation: Air injection system is monitored for faults. Probable cause: Circuit relay defective or fuse open; Check connector and wiring; air pump defective or hoses blocked.
Assume next step is to get all these items checked out. I did have a 'relay module' replaced a few months ago when the light first came on at a small repair shop. Many thanks from a happy Crossfire owner, '04, had it 3 years.

 

The P0410 is pretty common and usually no cause for concern
probable fault areas are :
1. the relay contacts for the air pump in the relay module
2. a defective air pump
3. wiring problems

The P0335 usually means you need to order a Bosch CPS sensor and replace it.