CEL's...What to do

[mcolliga]

I bought a 99 SR5 4wd, 3.4L in Pittsburgh two years ago. Right after it threw the P0420 code (lovely) and Toyota wanted $2600 to fix it. Since I was moving to Louisisna, I figured I'd just drive the pollution wagon and not worry about it. Now I'm finally getting around to clearing the light.

Just installed new plugs and wires, then checked the codes and it gave me p1135 and p0125, which apprently is the coolant temp, which I know there's nothing wrong with. Gas mileage has been a steady 16/21 for two years so I'm not too worried it's anything more than a sensor. My truck does have a Cali emissions setup so I'm confused as to which sensor to check/replace first.

I also replaced the gasket on the rear sensor that was missing, and fixed an exhaust leak around one of the hangers (maybe the reason it's not throwing the p0420 anymore).

Any suggestions?

 

[TheDurk]

I bought a 99 SR5 4wd, 3.4L in Pittsburgh two years ago. Right after it threw the P0420 code (lovely) and Toyota wanted $2600 to fix it. Since I was moving to Louisisna, I figured I'd just drive the pollution wagon and not worry about it. Now I'm finally getting around to clearing the light.

Just installed new plugs and wires, then checked the codes and it gave me p1135 and p0125, which apprently is the coolant temp, which I know there's nothing wrong with. Gas mileage has been a steady 16/21 for two years so I'm not too worried it's anything more than a sensor. My truck does have a Cali emissions setup so I'm confused as to which sensor to check/replace first.

I also replaced the gasket on the rear sensor that was missing, and fixed an exhaust leak around one of the hangers (maybe the reason it's not throwing the p0420 anymore).

Any suggestions?

That set of codes is usually the front (A/F) sensor. It will NOT be the rear one.

The coolant temp sensor part just means the A/f is sending incorrect signals that suggest the engine is cold, but the temp sensor says (correctly) that the engine is warm. For some reason, it trusts the A/F more than the temp sensor. (This is my personal theory, but I think I'm right.)