My VE-5 keeps throwing a code 33 intermitently. It was doing this for awhile with my 6 month old O2 sensor. I finally went ahead and got another brand new Bosch O2. I put the new one in, and it runs fine for a week or so, then Boom! Code 33 again. I've been through 2 new O2's now, and know that it is not the actual sensor itself. The car will run fine with or without the CEL, but then it will randomly stutter around 2100-2300 RPM @ partial throttle. It will shake decently when I'm decelerating without the brakes right at the same RPMS. It almost feels identical to really bad drivetrain slack. On startup I notice now that the car will really stutter for the first 20 seconds driving in cold weather. I'll rule out some things, I very recentely:

Cleaned Entire IM. (Spacer Install)

Cleaned IACV.

Cleaned Entire TB.

Cleaned MAFS.

Cleaned TPS.

Cleaned CTS.

Replaced EVERY Vacuum Line.

Replaced EVERY Fuel Line.

Blocked/Resistor EGR

New PCV Valve.

New Air Filter.

New Plugs.

I'm 95% sure that the issue has nothing to do with all of the above. I'm very very meticulate about maintenence on my car, and how it runs. I check all these things all the time. I have not one other issue with this car. Like I said, the problem is (OFF & ON) regardless if the CEL comes on or not. What other issues, could the code 33 mean? Can that code be traced to something else other than the O2 sensor? Maybe O2 harness or harness wire?

Any help would be greatly appreciated.

 

I had some of the same problems, turned out to be a bad Coolant Temperature Sensor. Would definitely check it. Might just be worth the $20 at Advance Auto or whatever to throw a new one on there...

 

if the CTS doesn't help then I'd be highly suspicious of the ECU

 

Initially, I would say buy a new coolant temp sensor instead of cleaning the old one. They are inexpensive and easy to put in. Maybe it's throwing a code 13 and not 33?

If that isn't it, what kind of mpg are you getting?

Have you noticed any excess fuel burning?

How dirty did the o2 sensor look when you took it out?

Maybe somehow you are running really rich and it is really doing a number on the sensor. Just a thought.

 

duckman, do you have a fsm? there is a diagnostic procedure for tracing a code 33. i have a hard copy so i can't post it for you but maybe some one has an electronic copy

 

I will try replacing the CTS, and see if that helps.

I have no excess fuel burning.

The O2's weren't very dirty actually.

And surprisingly, I've been getting 370 Miles/Tank around town & 450 Miles/Tank highway. Even with the Code 33 off & on.

 

http://s164.photobucket.com/albums/u...0sensor%20fix/

 

What was the whole procedure for your fix?

 

followed FSm diagnostic procedure, isolated ground wire as being bad, looked at it, saw it was bad, went into my glovebox, grabbed a splice and some wire, and fixed it.

edit: fixed it means i spliced the sensor-side ground wire back to the scerw in the cat's heatshield thingy.

 

When my CTS was bad I was running really rich, black smoke out of the exhaust at startup rich... Soo, although it is unlikely you are running rich (judging from your mileage) perhaps that could be the case, and it is making your o2 sensor throw a code? Just a thought since I had my o2 replaced twice when I was trying to figure out what was wrong with my car and it was no help...

 

That's what I was thinking, but he seems to get good mpg and not running rich.

That ground might be a problem, too.

These damn cars and their worn out crap...

 

Well fellas, I replaced the CTS. It got rid of the shaking and the 20 second cold start stutter. Cars been running great, but sure enough after a few days..........CEL (33) again!

What will trigger a 33 other than the actual sensor itself? The problem is deeper.

I need to get this figured out, it's driving me nuts!

Thanks for any imput.

 

Did you reset the codes in your ECU? Leave your battery cables off for 24 hours if possible or clear them via the diagnostic procedure on your ECU.

 

Yes, it's been reset. The code is intermitent anyways, it's off/on about one day a week or so.

 

sounds like a loose connection

 

Hmmm.......... That sounds very likely actually. I'll look into the connections.

So nothing else will trigger a 33?

 

Loose connection or wiring issues (many possibilities obviously)

I'd say there's a 96.73% chance the problem is in the circuit itself and NOT the ecu.

 

What's the best way to diagnose the problem within the circut?

 

DVOM, scope, and patience

 

I recently dealt with a wierd problem like this. My wideband would read off the scales RICH sometimes. Then it was fine. Well I tried finding the problem, but couldn't since it was so intermitent.

After months of this, it finally started reading RICH more often. I still couldn't find the problem. I opened my FSM and did everything it said to do. NOTHING. I would test the circuit between the ECU and o2 sensor and the signal wire was fine. Well, I found out that just b/c the signal wire has continuity, it doesn't mean the ECU is getting a good signal from the o2 sensor. My problem turned out to be a lose signal wire. It was obvious when I pulled on the signal wire and it fell out of the subharness connector!

Also, the chances of a new Bosch o2 sensor of being bad are very slim. I went through about 3 brand new ones, including 2 junk ones I had in a box. I bench tested them all with a multimeter and propane torch. They were ALL in good working shape. When you bench test an oxygen sensor, you first get it glowing red with propane torch while looking at the voltage reading you are getting from the multimeter. Once it's up to temp, then when you pull the flame away from the sensor, the multimeter should react INSTANTLY. Then put the flame back on it and the voltage should react INSTANTLY.

I'm sure your o2 sensor is fine. There is something wrong with the circuit. The chances of the ECU being bad are slim also. But if you have a spare one laying around, try it.

But start with following the diagnostic procedures in your FSM. Do the o2 sensor procedure and make sure the CEL shows the sensor toggling back and forth within the specified time period. But my guess is a circuit problem, not the actual o2 sensor being bad.