P0135 code. Now what?

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Chances of it being the ECU are fairly slim. If you look at your O2 Sensor, you will see a 4-wire connector. On the replacement sensors, there are two white wires.These are for the heater. Sensors are pre-heated now so they work without having to warm up. This is what the code is telling you. Unfortunately, it doesn't seem to tell you, upstream or downstream? I have been worng, oh, once or twice, but I would get under the car and look for the downstream sensor, and look for cut or dangling wires. Actually, you could start under the hood...it's a lot easier!

As far as troubleshooting? Well, not knowing the colours, it'd be hard to say, but if I could find out what wires go to the heater, I'd pull the sensor, hold onto it while i applied 12 volts and see if it got warm.

Thanks. Actually, the fault code output also pointed to "Bank 1 Sensor 1", so I would imagine it being something to do with the sensor on the exhaust on the cyclinder bank near the firewall (v6). If the sensor ends up needing replacement, can it be repaired and is there a trick to yanking it and with what size socket? or do I need a special tool to fit around the wires while pulling it?

On the V6 B1S1 (Bank 1 Sensor 1) is the rear manifold, B2S1 is the front, B1S2 is the one after the catalytic converter.

You can try a 7/8" box end wrench - thread the wires through the box end. You can also get a special socket to remove the sensor which allows you to tuck any wires up inside the socket. Try your local auto store.

Thanks, Travis. With the cost of the sensors so high (at least here in Canada) can they be repaired? What's the best method of determining just why the part failed? ie, should I be looking further upstream for a problem, or will the ECU monitor have coded another one along with the P0135 O2 malfunction?

They just fail, Wayner. I've seen some last for 20K miles or less, get replaced and then have the replacement work for the life of the vehicle. They are not repairable.

Buy the OEM sensor online and save a few bucks.

Thanks for that info, Travis. We have local parts suppliers and, being in Canada, buying from the States is hit and miss so far as prices, s/h, duties, yada yada are concerned. I noticed that some places (sites) suggest using universal O2 sensors (NTK and Bosch make em). Are they a good alternative? Will they fall within specs for the car? I won't mind splicing out the sockets if it saves a few $$. Wayne

(NTK and Bosch make 'em). Are they a good alternative? Will they fall within specs for the car? I won't mind splicing out the sockets if it saves a few $$.

The universal replacement sensors should work fine. Denso and Walker also make "direct fit" sensors that include the wiring harness and connector; personally, I'd prefer one of those just for convenience.

Well well well.. I found a problem while trying to disconnect the harness for meter testing, Travis. When I turned the 4-wire connection over I discovered that it had been heat-welded to the manifold! I temporarily pulled it away and separated it and reset the code (I wonder if floating these things is normal manufacturing?). I tried to do a 'drive/trip cycle' in order for the monitor to set but it just keeps flashing (on the reader) so obviously there is a specific driving event that is being looked for. I'll drive it for a couple more days and see if it sets, no code is generated and the MIL remains off. So now I have to either go to the dealer and buy a complete harne$$ anyway, or find a wrecker with one ..none around here with one. Drat. Wayne

Boy, I can't remember what I used. I think it was an 11/16, which was close enogh in tolerance not to be a problem. I doubt it can be repaired easily. In theory, since it is only a heater it should be repairable, but I think the case would be destroyed in the process, rendering the sensor useless. An OEM Toy sensor is about $135 and will probably last the rest of the life of the car. An aftermarket one could run half that and last half that. I have bought them for as little as $19 for an old mid-80's style.

Another test you can try is by turning the key to the on position, disconnect the sensor in question and see if the heater wires at the connector are energized with 12 volts. If you haven't got 12 v there, the heater's not going to fire up.

Where did it wreck the wire? Can you just splice a new piece of wire in there, or did it compromise the connector itself? Remember, splicing is our friend! Since it was the heater wire it may not have damaged the computer, but there may be a blown fuse somewhere. Unfortunately I can't tell you which one and I don't think the manual will either. Look in the box under the hood.

I think the contacts inside the connector may have either grounded out on the manifold or shorted to each other as the connector is a mess. That could be what caused the MIL and fault code. But it cannot be pulled apart anymore to test. Check the picture I have posted here:

I have scoured the Web and sent emails out to various wreckers, but so far no replies.

If anyone out there is parting out a Camry & don't mind letting me in on this connector please drop me an email and perhaps we can work out something.. I'll repost this request to the alt.toyota NG also.

Wayne

As noted earlier in the Post, I can no longer pull the connector apart to verify test. Now looking for a replacement connector to splice in.

Actually, I beleive any four-wire connector from just about anything since

1995 will work. I saw your post and link, and it looks like the same connector I had in a '95 Tercel.

Right on. Thanks. I'll see what my post brings. Wayne

Further.. I hopped into the local boneyard and found several Toyota (diff models) wrecks there, but I didn't count on the fact that the engines were already out and with them part of the harness connector, and most were clipped anyway. So I realized this was going to be next to impossible to find an exact match. I then skulked around other makes and found a Nissan with the engine still onboard. There was a 4-prong hd connector, which they gave me! A bit bulky but it will do. I'll wrestle with the original wiring in my car and do a nice neat splice job. If a new sensor is needed, I'll find a "universal-type" and stick that in with the splice.

Any idea if by what they mean as "universal" is that it fits any engine with the same thread pitch? ..do all O2 sensors have the same spec?

Wayne