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1999 Toyota Solara check engine light P0125, P1133, P1135

The check engine light for my V6 Toyota Solara is on for the codes P0125, P1133, and P1135. I changed the Bank 1 oxygen senor in addition to the temperature coolant sensor. During the drive back home from the mechanic the check engine light came back on, so I went back to the mechanic and was told that maybe the sensor was defective. The Denso sensor was exchanged, but again, the check engine light came back on. What do you think is the real problem? Have I been buying faulty parts or is there a different problem?

If it helps, the first time the oxygen sensor was changed smoke started coming out from the exhaust and from under the hood.

Can Your “Mechanic” Access Toyota Technical Service Bulletins ?

Diagnostic Trouble Codes don’t tell you what parts to replace, but rather what circuits indicate a fault, sometimes caused by defective parts.

I believe TSB # EGO13-98 will possibly solve all of your problems without replacing any more parts and it takes minutes, not hours, to do the work.

Some 1999 California Specification 6-Cylinder Solaras (prior to VIN: 2T1CF22P*XC104577) develop false codes for any or all these codes: P1133, P1135, P1153, P1155, or P0125.
The condition is caused by an open or poor connection at the terminals beneath the Air/Fuel Heater relay in the bottom of the relay block.

Secure those connections and Voila! This could possibly fix everything.


You should absolutely check out the TSB provided by CSA above. If that doesn’t help then get a new mechanic. (Or maybe you should get a new mechanic anyway).

If you have a P0125 and then some A/F sensor (O2 sensor) codes you don’t touch the A/F sensor issue until you’ve cleared up the P0125.

The P0125 is about the engine not getting hot enough to get to closed loop operation - closed loop operation is where the computer is using the O2 (A/F) sensors to do the fuel/air mix. So if there is an issue such as the P0125 then you don’t trust anything from the O2 sensors until that is right.

Do you know why the coolant temp sensor was replaced? Was you thermostat checked? Was the actual coolant temp measured? Was the temp sensor actually checked?

Anyway, hopefully cleaning up the connections mentioned by the TSB is all you’ll need to do. But if not then worry about your choice of mechanic.

Cigroller’s Right. Ordinarily A PO125 Could Be Thrown By A Stuck Open Thermostat Or Low Coolant, Besides The Coolant Sensor That Was Replaced.

Also, P1133 and P1135 could indicate a problem with bank 1, sensor 1, oxygen sensor, but how are all those new sensors working for you ?

I’d have somebody invest fifteen or twenty minutes on performing the TSB and see how she rolls. Work smart, not hard.


The sensor I have in the car now was working after being installed. I’m assuming its not working now, since the check engine light came back on. I haven’t asked my mechanic if he can access TSB. Is there anyway I can view the TSB on my own?

Have You Tried Searching For The TSB ? How About Befriending Somebody (Parts or Service) At The Local Toyota Dealer And See If They’ll Print A Copy For You ?


Yeah I tried looking up the TSB and found one that required a subscription. I thought I’d look under the hood myself for loose wires or anything. I noticed that the coolant level was extremely low and I noticed a lot of grease around some of the wires.