0 reading from o2's???..
12-13-2008, 03:55 PM
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0 reading from o2's???.. Car was running like crap plugged it in found out that the o'2s had a zero reading on both the front ones (back ones were fine) so i went ahead and exchanged for the second time cause there stilll under warranty plugged the new ones int and still nothing.... what would cause this? there bosch 02's btw
12-13-2008, 06:44 PM
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I'd say there is a break in the signal wire. If you don't see anything visually, check signal voltage at pin 8 for B2S1 and pin 20 for B1S1 at the PCM connector with car at operating temp. Here's a reference http://shbox.com/1/1995_pcm_conn_c.jpg
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12-14-2008, 03:10 PM
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An o2 sensor creates it's own voltage (no power and ground), so all it has is a signal wire going to the PCM. Check that wire!
12-14-2008, 09:01 PM
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Actually there is a o2 fuse. It's for the heater element though. However, the sensor SHOULD still work even if the fuse is blown IF the car is at operating temperature. All it does is heat the sensor up more quickly. 1993 models don't have heated o2 sensors so that's why I assume it should still work. But that doesn't mean you should over look that fuse.
An o2 sensor creates it's own voltage (no power and ground), so all it has is a signal wire going to the PCM. Check that wire!
An o2 sensor creates it's own voltage (no power and ground), so all it has is a signal wire going to the PCM. Check that wire!
i will defanatley check that wire....is there a possibilty that the connector that the o2 plugs into could have gone bad??
12-14-2008, 09:21 PM
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Well anything is possible. The connector could be loose or the pins might not be secure. First check fuse 6 in the underhood relay box. Then I would get a volt meter and check the voltage from the purple wire (signal wire). That will let you know if the o2 sensor is giving a signal to the PCM. You could follow the wire and measure the voltage where it connects to the PCM, and you should have the same readings. If not, the wire is broke somewhere. And if you are getting the signal to the PCM but your scanner says there isn't a reading, the PCM has to be bad.