PO137/340 and 341

[Mason648]

I have a 98 SL1 1.9 L with 138000 miles. My service engine light will come on and then go off at what seems at random. I took it to the Advanced Auto and they said the codes they were getting are PO137 340 and 341. I am not sure what these mean and how do I corect he problem. Any help would be appreciatd

[2NDSOUT]

P0137= http://www.obd-codes.com/p0137, Possible Bad O2 Sensor

P0340= http://www.obd-codes.com/p0340 , Possible Bad CPS

P0341= http://www.obd-codes.com/p0141 , Possible Bad O2 Sensor

[madpogue]

Originally Posted by 2NDSOUT

P0137= http://www.obd-codes.com/p0137, Possible Bad O2 Sensor

This is in reference to the REAR O2 sensor. It's in the outlet of the catalytic converter. Typically it means just the sensor is bad, but if you are having performance problems, and if your exhaust feels weak out of the tailpipe, suspect a failing catalytic as well. You may not have much choice anyway, as (according to one of our techs [Squareback?]) the rear O2 sensor was frequently cross-threaded on installation at the factory, and with years of rust and heating/cooling, that sensor may not budge.

P0340= http://www.obd-codes.com/p0340 , Possible Bad CPS

The CPS this article refers to is the CAMshaft position sensor. Our cars don't have one. With the S-Series, ANY mention of the CPS refers to the CRANKshaft position sensor. The two have nothing to do with one another. AutoZone is famous for selling S-Series owners a CPS when they throw a 340 or 341, when they have NO need for it. At one point, it was even listed as an "alternate" when you searched for a (non-existent) cam position sensor on their web site (I *THINK* they've remedied that).

P0341= http://www.obd-codes.com/p0141 , Possible Bad O2 Sensor

The link is to a page on P0141.

P0340 and P0341 both refer to the non-existent CAM position sensor. In our cars, they indicate a general ignition system problem, impairing its ability to "fake" the sensor signal based on when the #4 spark plug fires. To remedy, check/replace the spark plugs and wires, and make sure the coils and ignition module are properly grounded. Wolfman has several photos in his gallery showing how to do that.

[Mason648]

Thanks a lot for all the help, I'll go see if I can find the photos for the coils. Any idea what it will cost for the O2 sensor on the converter?

[2NDSOUT]

You CAN buy O2 Sensors for inexpensive from your favorite flavor auto store. If you buy one from the dealer it will be at least $70 or more.

The Cat Converter is not something that is cheap either, unless you have connections thru a muffler shop. I'm sure you can get them cheap; but as I don't have the tools in my garage to weld a new Cat Converter in place. They would probably run you anywhere from $100-$300? Just taking a guess there, I'm sure there are others that would be able to give a more accurate monetary figure.