1/14/15 – Filled up with gas and left the gas cap off. Check engine light came on about a mile down the road. Put the gas cap back on.
1/15/15 – Check engine light went off after about 75 miles.
2/5/15 – Check engine light came on. Tightened gas cap.
2/10/15 – Replaced gas cap with one from Toyota Dealer parts department
2/17/15 – Replaced O2 sensor at Local mechanic (also oil change, tire rotation, muffler)
2/18/15 – Check engine light came on. Local mechanic assumed defective part and replaced O2 sensor
2/19/15 – Check engine light came on. Returned to Local mechanic and they checked for an electrical problem that might be triggering the problem, but did not find any issues. They said they would order an O2 sensor from Toyota.
2/23/15 – Replaced O2 sensor with Toyota part. Idled car and drove it for about 30 minutes with no problem.
2/24/15 – Check engine light came on on the way to work. Called Local mechanic and we agreed I should take it to the dealer (and if they replace the O2 sensor again, to bring it back and they will refund me)
2/25/15 – Code checked at Advanced Auto – Bank 2, Sensor 1 – same sensor that has been replaced.
The part that bothers me is that these guys are making a lot of assumptions that the oxygen sensor is bad, and they keep replacing it. And they’re not following through to make sure the problem is actually resolved. Pretty sloppy work practices, in my opinion
I think more real diagnosis is needed. Maybe if a more experienced guy works on it, or somebody who is good at finding the technical information needed to perform a proper repair.
If you post the exact fault code, I’ll try to post some information
In any case, it’s good that you installed genuine Toyota parts
I’m wondering if you might need a software update for your powertrain control module . . .
My mistake, sensor that is causing issues is Bank 1 Sensor 2. The error codes on 2/17 were P0136 (o2 sensor circuit b1s2), P0138 (o2 sensor circuit high voltage b1s2), and P1578 (brake system malfunction)
P0138 can be challenging to diagnose on this vehicle. The following is from a service bulletin for your vehicle;
Check the A/F and O2 sensor values for the appropriate bank DTC Freeze Frame Data (FFD).
Is the AFS Voltage B#S1 = 3.35~3.70V AND the O2S B#S2 = 0.70~0.90V?
• YES — Replace the appropriate bank Air Fuel Ratio Sensor ONLY (NOT O2 Sensor) to
correct the P0138 or P0158 DTC condition.
• NO — Inspect the O2 B#S2 circuit for open, short, or high resistance. If no trouble is found,
refer to TIS, applicable model and model year Repair Manual for P0138/P0158 diagnosis:
The problem is likely the air/fuel sensor (bank 1 sensor 1).
@Caddyman Toyota made this difficult to ignore… when the CEL comes on, the 4WD and VSC and cruise control also stop working. I live in NY and will be inspected in June.
@Nevada_545 thank you! I’ll have them check that out.
I hate to say it, but 150K seems in my experience to be about the normal life of OEM Toyota catalytic converters. Sensor 2 is the one that provides the comparison signal for the ECU to monitor the cat converter’s performance.
The Rav4 had two engine options, one a straight four and the other a V6. The straight 4 simply used “bank 1” to designate a failure of its only downstream O2 sensor. “Bank 2” would only be used for the V6. Would I be correct in guessing that yours is a straight 4?
I commend your shop, by the way, on their apparent honesty in being willing to pay for a dealer to replace the sensor a second time without quibbling. They sound honest to me.
I agree with @SteveC76 . . . Toyota’s cylinder bank layout is not at all like Ford or GM, and they aren’t the same, either, for that matter
Bottom line . . . unless you’re absolutely sure about the cylinder bank layout, look it up
i’m mentioning cylinder bank layout, because you can’t know where O2SB2S1 is, if you don’t know where bank 2 is
I too . . . on various brands . . . have seen the wrong sensor replaced. Because the mechanic thinks “Well, on brand x, this is bank 2, so I’ll just assume the same thing here”
Here’s an offbeat idea. The brake warning code could mean a problem with the brake booster. If there’s a leak there that is allowing unmetered air into the intake manifold, that could confuse the ecm enough it might believe there’s a o2 sensor problem, when in fact the o2 sensor is working and telling you there’s just more air in the exhaust than there should be for the amount of gas being injected. A fuel trim real time reading might help in the diagnosis.
OP, at the very least ask your shop to make sure the brake booster is holding vacuum like it should and not leaking air into the intake manifold.
Thanks everyone. (It’s a 4cyl.) The dealer was able to diagnose it as an Air Fuel Ratio Sensor problem. They replaced it and I took the car on a 2 hour drive immediately after. No problems, and the engine is running much more smoothly… I hadn’t noticed how choppy it had gotten.