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Sensor faults Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Thu, 13 Jul 2006 18:35:50
In Reply to: Re: Grounding, TML   [Profile/Gallery]
, Thu, 13 Jul 2006 12:59:45
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Well, since it isn't the 0133 - slow sensor - the slow sensor fault criteria doesn't matter. (By the way, it is speed = 0, engine idling, close loop active, coolant >60C, heater current Off (<1.5A) and the sensor performs less than 14 transitions in 250 engine revs.)
I can't find 0131 in the Trionic manual. The most I can find is 0132, which is the sensor voltage >1.5 volts for more than 5 seconds, with the ignition on. Since the output of an O2 sensor should be about 1.0 volts max, this fault is reasonable.
Two things come to mind - the first is that you are getting a sneak path in the sensor, causing the sensor voltage to appear too high. This could be moisture in the sensor, or a wiring issue. It is interesting that the front and rear O2 sensors share the ground pin (47 on the ECU), and that voltage can move around - it isn't always zero.
I would try a few things-
First, pull the O2 heater fuse (fuse 28). This should trigger an 0135. If the other fault goes away, I'd suspect the heater voltage is getting into the O2 signal.
If that doesn't do it, unplug the rear O2 sensor connector. It's possible that an issue with the rear sensor is messing up the common ground. I'd have to think long and hard on how that would do it.
Since the four-wire O2 sensor has a ground wire, the sensor wiring can do something the old ones couldn't - it can be wired backwards. It would be important to make sure you get the polarity right on the sensor. And equally important to get it right on the rear sensor. According to the manual, the low (ground side) of the stock front sensor is grey and goes to pin 47 of the ECU. The high side is Black (go figure), and goes to pin 70 of the ECU. For the rear sensor, the colors are the same, and low is still 47 and high is 23. If you really want to track this down, I'd suggest getting a good voltmeter and take some measurements. I'd measure the voltage between pins 47 and 70 - make sure it is around 0.9 volts. If it's greater, something is sneaking voltage in. The other thing I'd do is measure the voltage of pin 47 to ground at the ECU. It should be less than a volt. If it's greater, voltage is sneaking into the 'low' side. Of course, these checks must be done with the connector on the ECU, so you'll have to sneak in from the back of the connector.
posted by 12.76.128...
, Thu, 13 Jul 2006 07:58:26, Thu, 13 Jul 2006 09:31:00, Thu, 13 Jul 2006 09:51:52, Thu, 13 Jul 2006 12:56:28, Thu, 13 Jul 2006 11:40:37, Thu, 13 Jul 2006 12:59:45, Thu, 13 Jul 2006 18:35:50 <-- Viewing This Message, Fri, 14 Jul 2006 07:31:16, Fri, 14 Jul 2006 10:39:23, Fri, 14 Jul 2006 15:07:56, Sat, 15 Jul 2006 19:55:13, Fri, 14 Jul 2006 09:14:51, Fri, 14 Jul 2006 08:58:43
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