First, Happy New Year to everyone!
Second, we had a "O2 sensor 1, bank 1 slow to respond" code. Sensor - actually, seems to be just one upstream on our '96 V8 EB - was replaced, but the code returned. What would experience say about the other possible causes of this warning? TIA and greetings, Zbysko
If you can post a few details..... year, engine size, the code itself, I might be goaded into getting my laptop from the Ex (dealer tech site appears to be down right now and I am what you call lazy). In the last ten years, I have replaced very few O2s..... mechanical problems are a more usual cause of codes.
Jim Warman snipped-for-privacy@telusplanet.net
Thanks for the prompt response , Jim. Car is '96 EB with V8 engine, has 110 kkm. It had one O2 sensor replaced by the dealer at around 75-80 kkm. This CEL came on some time ago, then went off for a few days, and finally came back on to stay. I had car scanned at local shop, mechanic showed me the scanner display and while I forgot the exact code, explanation was "Sensor 1 bank 1 slow to respond". He reset the PCU, but the light came back few days later. Then I replaced the sensor and cleared the PCU memory (by depowering the system), but the light is on again after few days. This car appears to have only one upstream sensor, and it is on the driver side exhaust manifold. If sensor is fine, what other things might possibly invoke the code? Any leads would be appreciated. TIA, Zbysko
You should have a total of 4 O2 sensors (two upstream and two downstream). Bank one is the side with cylinder # 1 which is the passenger side. If you replaced the O2 sensor on the driver's side, you replaced the wrong one. Also, just because you get an O2 sensor fault code doesn't always the sensor is the cause. If you are pushing 90K or more miles without having replaced the O2 sensors, then it is getting close so the code is likely due to a bad O2 sensor. You will have to look around some more on your passenger side manifold to find it.
Sensor1, bank 1 will be on the passenger side (as Alpine pointed out, you do have 4 .. 2 upstream of the convertors and 2 downstream of the convertors). Possible causes for slow response include a defective sensor, exhaust or intake leaks, or improper fueling.One might also suspect the MAF but I would expect this to affect both banks at the same time.
The only exception to the O2 sensor placement rule will be those exhaust systems with 2 upstream and one downstream sensor (located, naturally, in that part of the system where the exhaust from both banks travels through one convertor). Since you have already purchased a new sensor (hopefully, you haven't disposed of the old one), I would suggest installing that in the location for HO2S11, clear the codes and the KAM (disconnecting the battery cable also clears the Keep Alive Memory) and see if that does the trick. With That many miles on the car, it wouldn't hurt to inspect the MAF and clean it if necessary while your hands are dirty.
Brake cleaner usually suffices for this, be sure not to touch the sensing elements and let it air dry completely before reinstalling it.... oh, and don't lose the o-ring.
Jim Warman snipped-for-privacy@telusplanet.net
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