'99 Suburban - Check Engine Light Problem

[Mom_Bus]

The check engine light came on. Took it to a shop and had the oxygen sensor replaced. Said it was reading funny and might need to have catalytic converters replaced too. He reset the check engine light. Week later, it came back on. This time it read catalytic converter to be replaced. Did that. A week or so later, light came back on. Stayed on for about a week and went off for 2 days. Came back on. Checked coolant and it was low. Added coolant to both radiator and overflow. Light went off after a day. Week later, light is back on.

Am planning on taking it in again to have the code read, but this is getting a little frustrating. My father-in-law heard there was a known problem with some chevy check engine lights, but couldn't go into details.

Any suggestions or known problems?

(I am new to the forum and was hoping I didn't have to try to read through all of the old posts, so please forgive me if this is a duplicate)

[Mom_Bus]

I took it to Autozone and they said it was reading
Inadequate Catalytic something (Bank 2)

We already changed one O2 sensor and the Catalytic converters. He mentioned it was probably the other O2 sensor.

He cleared the code and I am waiting to see if it comes back on.

Can anyone tell me if changing the other O2 sensor sounds like the correct solution?

[Pamsdad]

I'd be more concerned/look into low coolant problem...

[JAG40]

I'm having a similar problem with our '99 Suburban. SES light came on, let AutoZone read the code, and replace the front bank O2 sensor on passenger side. Clears the code for a day and then comes back on. Get them to reread the code, now it says the rear bank O2 sensor on the same side. At $85 a pop I'm not willing to let them assist me. I pull out the manual, get the multimeter and check the reading at the sensors while running. Front bank reads between .1 and .9 volts as the manual says it should. Rear bank reads .4 at idle.

Now I'm interested enough to buy a code scanner/data logger. I get the Davis carchip ex and hook up the laptop. Error code is P0430 - Catalyst System Efficiency Below Threshold. O2 sensor data stays within above parameters. I reset code and it stays off a day and comes back on. Any suggestions?

[Mom_Bus]

I'll keep an eye on it. The SES light hasn't come back on since Autozone cleared the code. All of the gages seem to still be reading fine.

I'll post more if it comes back on.

[stubbornmike]

If you needs new o2 sensors there a site online where i bought mine for 45.00 each for bosch..
if you need the web page let me know and ill search for it!
check engine light hasnt came back on and i have lots of power again!

[hboker]

Originally Posted by stubbornmike

If you needs new o2 sensors there a site online where i bought mine for 45.00 each for bosch..
if you need the web page let me know and ill search for it!
check engine light hasnt came back on and i have lots of power again!

what is the site where you purchased your sensor/ thanks

[stubbornmike]

oxygensensors.com
has cheap 02 sensors starts at 43.90 for your vehical.. if you order two its free ups shipping. It looks like they replaced there bosch with denso but denso is a better 02 sensor i think.. i would have prefered a denso my self.


mike

took me about a week to recieve my 02 sensors I replaced all 4 and tuned up my suburban with doulble platinum plags and it passed smog way below national average.