I have a 2000 Tacoma w/ check engine light. Just checked codes and got both P1130 & P1135. Wondering if these codes are due to removal of CAT when previous owner installed exhaust. I live in Hawaii and CAT not required for smog checks.

If that is reason that I'm getting error then easy to clear. Is this causing my truck to run poorly?


Engine mods:
K&N Air Intake (not just filter)
Flowmaster Exhaust

many mahalos

 

All signs point to the front air/ fuel sensor.

 

^^^Yep. P1130 is signal circuit problem (one pair of wires) and P1135 is heater circuit problem (the other pair of wires) so I wonder if it is there at all?

You need a front A/F sensor big-time with or without the cat. The back one you could live without, but those are different codes. (I'm very surprised you don't get those with no cat, especially P0420.)

Without the front sensor, ECU is forced to run in open-loop (start-up) mode. This tends to be richer than it would be in closed loop with a working A/F, effing your mpg's and performance in general, and would also kill your cats if you had any.

 

All that being said, OP, when you replace the front AF sensor, use only a Denso sensor. You can get one for a good price at underdogracingdevelopment.com.
The parts store "universal" sensors tend to not work well with the Toyota efi system.