Pop N Wood Posted May 9, 2006 Share Posted May 9, 2006 Anybody have any ideas on what would make a car burn out the O2 sensor heaters? Last year my wife's 2001 Toyota Sienna had the heating elements go out on both primary O2 sensors. They went out 1 at a time within 2 weeks of each other. Two weeks after that I got the smog check notice, so had to fix them. Today, only 12,000 miles later, the computer threw error codes for BOTH heaters at the same time. This van has the wide band types. At $250 EACH from Toyota ($300 each for the Bosch units at Autozone) I do not want to replace them until I know what is going on. What the F could cause both heaters to go out at the same time? All I have is the codes right now, but the ones I took out last year are open circuits when checked with an ohm meter. The van seems to run fine. Any chance I could splice a 1.2 ohm resistor in place of the heaters and not have the engine run bad? Quote Link to comment Share on other sites More sharing options...
Okimoto Posted May 10, 2006 Share Posted May 10, 2006 check this relay, maybe it's stuck in the on position. Maybe you can set it on some kind of timer to go off after 9 minutes of driving? Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted May 10, 2006 Share Posted May 10, 2006 you might also think about if youve used alot of injector cleaner products or if the engines starting too burn oil, (rings, valve seals) as alot of residue on the o2 sensors tends to make them run hotter just like the CATS under those conditions Quote Link to comment Share on other sites More sharing options...
Cruez Posted May 10, 2006 Share Posted May 10, 2006 While we are on the same note... If I am installing this type (4 wire) on a car without that circuit.. I am assuming I need to put them on a timer , correct?? Quote Link to comment Share on other sites More sharing options...
Okimoto Posted May 11, 2006 Share Posted May 11, 2006 yeah, I think a timer would be good for it. Maybe time it for 10 minutes in the morning or if you have some kind of choke system, you can tie it into that with a relay. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted May 11, 2006 Author Share Posted May 11, 2006 check this relay, maybe it's stuck in the on position. Maybe you can set it on some kind of timer to go off after 9 minutes of driving? Man, I owe you big. My POS Chilton manual didn't show an A/F relay or fuse. The manual made it look like the thing was powered directly off the ECU. Thought maybe your diagram was for a different car. But I poked around anyway and found the blown 25 amp fuse. $2.82 for 5 fuses and the light is out. Let's see if this holds up. Sure beats $500+ Thanks. After what I went through last year I overlooked the obvious. BTW, those heaters draw some amps. The Chilton manual listed the resistance as 1.2 ohm at 68° and 3.4 ohms at 1472°. Thats 10 amps-120 watts per heater. Those suckers get hot! Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted May 21, 2006 Author Share Posted May 21, 2006 Well, for anyone's future reference, when replacing O2 sensors make sure you secure the wires so they can't fall against the hot exhaust manifolds and melt the wires. Was easier to fix the second time around then I would have thought. Quote Link to comment Share on other sites More sharing options...
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