rverdoold Posted January 14, 2011 Share Posted January 14, 2011 Was driving yesterday on the highway all of a sudden CEL comes on for few seconds, and half a minute later again. And stayed off for the rest of the trip. Passed subaru dealer and managed to read the errors without charge (not very common here in Holland). Knock-sensor error, all codes cleared. This morning again CEL for just a second or two and then off. I Washed the car 2 days ago and cleaned the engine bay a bit with a sponge so no tons of water. Checked the sensor this morning. It is a 2 wire plug but there is only 1 wire. Engine is a 1.6 but is identical to the 1.8 (which is nearly identical to the 2.0) So what makes the CEL go on. I assume malfunction of the sensor it self. Or also when heavy knocking is detected? Since it is a single wire I think assume the grounding is via the engine block, anything I should check here before I buy a new sensor? Sensors cost here about 120 euros (which is about 180 dollars which is stupid). Car, 1999 Impreza plus, 1.6 with direct propane injection (108 octane) about 106k km (~66k miles) Quote Link to comment Share on other sites More sharing options...
Cougar Posted January 14, 2011 Share Posted January 14, 2011 (edited) It's fairly common for these sensors to go bad after time. If the code shows a circuit problem then there may be a bad connection to it but the sensor could just be bad also. It is a piezoelectric device that generates a frequency when it detects certain vibrations. It does ground through the engine. Edited January 14, 2011 by Cougar Quote Link to comment Share on other sites More sharing options...
rverdoold Posted January 14, 2011 Author Share Posted January 14, 2011 (edited) Would it make sense to take it out clean it and put it back and see for few days. I think it is only failing when the CEL is on. So only for short moments. If I get a replacement does it have to be Subaru, or Bosch or will others also do. (I know the ECU is picky with O2 sensors) Edited January 14, 2011 by rverdoold Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted January 14, 2011 Share Posted January 14, 2011 Would it make sense to take it out clean it and put it back and see for few days. I think it is only failing when the CEL is on. So only for short moments.If I get a replacement does it have to be Subaru, or Bosch or will others also do. (I know the ECU is picky with O2 sensors) it could be corrosion under between the sensor and the block, so checking for that and cracks in the unit itself isn't a bad idea. cracks is a common failure mode. but it wouldn't be a bad idea to have a replacement on hand just in case. they are kind of a pain to install, hard to reach, and challenging to get the bolt in without dropping it. make sure you note the position of the sensor and wire before you pulling, apparently it makes a difference . it is a simple device, any replacement from a decent manufacturer should be ok. no need for it to be a subaru part. Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted January 14, 2011 Share Posted January 14, 2011 When my knock sensor went bad on my OBW with the 2.5 motor, the CEL would come on, then turn itself off, for varying period of times. It is a rather easy do it yourself replacement job. It is kinda hard to find, if you don't know where it is, and what to look for. Assuming you know what to look for, it is best to use a wobbler and a short extension on a 3/8" drive to R & R. The reason for this, is that there is not a straight shot with a drive and socket to reach the sensor to remove it from the block. Using the wobbler, you can reach the sensor from an angle. Upon installing the new sensor, take care to not over tighten it. Just snug it up, to avoid damaging it. If you are talking the equivalent of $180 in USD, then that is expensive. Here in the U.S., I am thinking I bought mine for about $80 out the door about 3 years ago. You should be able to buy a knock sensor on line at a reasonable price. You can continue driving your car with a bad sensor for a while. However, your fuel millage and performance will suffer a little. Good luck on getting this repaired. Quote Link to comment Share on other sites More sharing options...
rverdoold Posted January 14, 2011 Author Share Posted January 14, 2011 You can continue driving your car with a bad sensor for a while. However, your fuel millage and performance will suffer a little. Good luck on getting this repaired. Thanks for the info. I know where it is located, found JECS for about 80 euros (still expensive compared to USA but better than 120) It is a 1.6 never mind the performance Quote Link to comment Share on other sites More sharing options...
Cougar Posted January 14, 2011 Share Posted January 14, 2011 Your comment about the sensor and the CEL light is correct. The light will change instantly with the status of the sensor signal to the ECU, good or bad. Make sure the connection to the sensor itself is good. If that is ok and you still have trouble then replacing the sensor will most likely be needed. Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted January 14, 2011 Share Posted January 14, 2011 It is a 1.6 never mind the performance Had four Rotarians from Holland visit our Rotary Club in Zionsville, IN last summer. They put on a good power point show and tell about Holland that was very interesting. I remember seeing some interstate roads in the presentation, but most appeared to be 2 lane slow driving roads, so I guess your 1.6 motor is sufficient. The group also said that gasoline cost was about twice as expensive or more compared to the US. No wonder you use direct injection propane. Quote Link to comment Share on other sites More sharing options...
rverdoold Posted January 14, 2011 Author Share Posted January 14, 2011 (edited) Most interstates are 2 lanes indeed, closer to the big cities as Amsterdam and Rotterdam they get 3 to 6 per direction. However speedlimits there are 100 km/h and on interstates are 120 km/h so not that fast. Keep in mind that most sold cars here are size of an Impreza or smaller. 1.6 is a real average and fast enough. Fuel efficiency, weight and co2 emmision determine the road tax with an exponetional increase for co2 emmision. Subaru is really really bad with co2. They should make a 1.5 turbo or even smaller, also a smaller diesel is welcome. Propane is a good alternative now, being very clean and green (is a waste product). And in bi-fuel configuration so spare tire is at behind the seat. Prices per gallon I will not calculate I figured out that JECS is actually the original supplier. Edited January 14, 2011 by rverdoold Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted January 16, 2011 Share Posted January 16, 2011 Most interstates are 2 lanes indeed, closer to the big cities as Amsterdam and Rotterdam they get 3 to 6 per direction. However speedlimits there are 100 km/h and on interstates are 120 km/h so not that fast. Keep in mind that most sold cars here are size of an Impreza or smaller. 1.6 is a real average and fast enough. Fuel efficiency, weight and co2 emmision determine the road tax with an exponetional increase for co2 emmision. Subaru is really really bad with co2. They should make a 1.5 turbo or even smaller, also a smaller diesel is welcome. Propane is a good alternative now, being very clean and green (is a waste product). And in bi-fuel configuration so spare tire is at behind the seat. Prices per gallon I will not calculate I figured out that JECS is actually the original supplier. Interesting road info you provided. I hope replacing the knock sensor fixes your problem. Let us know! Quote Link to comment Share on other sites More sharing options...
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