: History Codes ??? & P0420



gcontois
03-05-06, 10:56 AM
96 SLS. I recently had a Service Engine Soon light "on" condition and the culprit code P0420 showed up on the OBD msg. Both 02 sensors were replaced but the SES came back on a few days later. I cleared the P0420 code and it came back a second time. This time I took note on the 2 displayed HISTORY CODES : 1P1552 and 1R2255.

Anybody out there know what they mean? And any suggestions for the overall problem associated with the P0420? Thanks, George C.

FrankT
03-05-06, 04:49 PM
Sorry to give you some bad news but P0420 is a degraded catalytic converter. The oxygen storage capacity of your catalytic converter has degraded to a point were you are emitting excesses emissions. So the ony fix is replace the converter. Most likely was nothing wrong with your HO2S sensors.
As far as HISTORY CODES : 1P1552 and 1R2255. I do not know.
Frank

gcontois
03-05-06, 05:52 PM
Sorry to give you some bad news but P0420 is a degraded catalytic converter. The oxygen storage capacity of your catalytic converter has degraded to a point were you are emitting excesses emissions. So the ony fix is replace the converter. Most likely was nothing wrong with your HO2S sensors.
As far as HISTORY CODES : 1P1552 and 1R2255. I do not know.
Frank

Tks. Oh well....

ostinco
03-05-06, 07:27 PM
I had the same problem. Replacing 1 O2 sensor was labor and material was $180.00 and that didn't fix the problem. Yep most probably need to change that CAT..any suggestions where to goet that replaces. Dealer wants
~ $ 1K

FrankT
03-05-06, 10:30 PM
I had the same problem. Replacing 1 O2 sensor was labor and material was $180.00 and that didn't fix the problem. Yep most probably need to change that CAT..any suggestions where to goet that replaces. Dealer wants
~ $ 1K
WOW 1k that sounds like the whole exhaust system. Try a muffler shop or salvage yard. I think that the conveter is welded in, but they can cut it out and clamp in a new one.
Good luck to both of you,
Frank