Hello. I recently bought a 99 accord sedan 2.3 ulev vtec (f23a) 5mt. The guy I bought it from said the only code was for the o2 sensor and he had a scanner hooked up so I didn’t bother to check because why would he lie when I could easily check it. The day after I purchased the car I put a scanner to see what codes it was giving and there was a p1259 and a p0135. Im pretty sure if I replace the o2 sensor it will get rid of the p0135. I replaced the one before the cat but the code was still there. The p1259 is the one I’m worried about. I was looking around and saw that the valve timing oil pressure switch harness had one of the wires ripped off. I’m replacing the harness tomorrow but wanted to get opinions from others to see if that would solve the problem or not. As of right now I cannot go past 4k rpms. Hopefully changing the harness will fix it. I just want opinions to see what else it could be if not the harness. Thanks in advance!
Why on earth would you want to flog that little engine past 4000 rpm?
I need to get it smogged to put it in my name. I know the previous owner is usually supposed to get it but I drove about 40 minutes to buy it and we met up half way. I’m not sure but I think when it gets smogged the person doing it needs to rev all the way up. Yeah that’s the main reason.
I’d check on that, it’s sounds very doubtful to me.
On a v6, 70-80 mph runs 2000-2200 rpm. A little 4 cy ran about 3000 at 70. It may have a computerized rev limiter to not let you go that high. ust my two cents but I wouldn’t anyone running my engine that high.
The engine in my Dodge sometimes exceeds 5000 rpms before shifting, maybe I’m doing something wrong. If someone were trying to maintain 2000 to 2200 rpms while accelerating from 0 to 70 mph, I would have to go around them.
Thank you to all that replied. I was able to fix the p1259 but the p0135 is still there. I have changed both of the o2 sensors and I’m now stuck. Any suggestions? Thanks.
Depends where you live. In Maryland the smog tests consists of plugging the machine into the OBD-II port and reading for codes. No codes generates a passing grade.
Inspect fuse # 6 in the passenger side under dash fuse box.
Thanks. I’ll check that out. I appreciate the help
O2 sensors didn’t used to have heaters; for example my 30 year old Corolla’s O2 sensor has no heater. The problem with no heater , it takes some time, maybe 5-10 minutes, after starting engine before the sensor is hot enough to produce an accurate mixture measurement. Meaning the engine is polluting the air until the sensor heats up. O2 sensors these days have electrical heaters in order to allow the drivetrain computer to set the correct fuel to air ratio as soon as possible after engine starts. The heater reduces air pollution in other words. p0135 means the computer’s measurement of the O2 sensor heater’s electrical resistance isn’t correct. Could be a problematic sensor, burned out heater etc, or could be wiring or fuse problem. So common sense says the first thing to do is measure its resistance. I’d expect it to be in the 1-10 ohm range.
Thanks for the response. I really appreciate it. Also, are the sensors specific to each engine? The one I recently put in was a denso 234-4621 for the o2 sensor after the cat. And a Bosch 13075 upstream sensor. I had put the Bosch one first then denso after when the upstream didn’t fix the cel.
Yes. Several reasons.
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There’s more than one technology used. Technology differences are incompatible.
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Attachment methods differ.
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A certain physical size or dimension may be required.
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Electrical heater resistance may differ, has to be compatible to computer’s circuitry.
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etc etc … so always use the correct compatible O2 sensor for your car. Parts stores know how to figure this out. Different brands mght produce the same compatible sensor though. I tend to prefer to use Denso for Asian cars.