Saturn SL2 - 1998 - service engine soon light

My garage tells me that the “service engine soon” code in my 98 Saturn (around 50K miles) is for the secondary (?) air pump. They also tell me that the pump is working. They are stumped. They cleared the code and it came back. I’m not near a city where a former Saturn mechanic might be working. Is there a test/piece of equipment I should try to find at another garage? Can I continue to ignore this and just keep driving, without doing too much damage to the car? Any suggestions appreciated.

Don’t worry about it. It’s not going to affect the way your car runs at all.

I suspect that it will not cause any direct problems, but you will never know when a new, more serious problem comes along because the light will still be on. I would find another shop.

I drove my 1996 Sonoma for 10 years with the engine light on… some dumb sensor which was bad. As long as you have an oil pressure gauge, I’d say ignore the dummy light.

The secondary air system injects air into the exhaust stream to assist faster heating of the catalytic converter and assists the catalytic converter in the process of oxidizing CO to CO2 and Hydrocarbons to H20. Without the secondary air system the catalytic converter doesn’t get hot enough to convert the Hydrocarbons into H20. These unburned hydrocarbons then accumulate in the catalytic converter to where the catalytic converter becomes plugged where it no longer functions. This then results that the catalytic converter must be replaced.

There are three components in the secondary air system. The air pump, the check valve, and the solenoid. Any of these can cause a secondary air code to be displayed.

So if you operate the vehicle without the secondary air system functioning, eventually the cat will plug up. But you wouldn’t know that was occuring because the Check Engine light would be on all the time.



Does the Secondary Air Injector system do anything once the cat is brought up to temp? Or does is just speed things up from a cold start? Just wondering.


It does both. It assists the catalytic converter to come up to operating temperature as quickly as possible, and keeps the catalytic converter at the optimum temperature so the catalyst reaction can occur. This is done because the engine exhaust is not hot enough by itself to cause the reaction.