Help!

My '01 F-250 has been getting more attention than I have time for lately. My "service engine soon" light came on about 3 weeks ago. Wanting to fix the problem myself I took my truck to autozone to get a scan and determine the trouble codes - came up 0135 and 0155, 02 sensor heater circuit malfunction. Naturally they suggested I may have a bad O2 sensor. Not having looked at the CD I got from EBay I figured I'd try a couple new O2 sensors since I've always been curious if changing them does help with gas mileage. Swapped sensors, took the truck back to autozone to erase the codes and a couple days later the light came on again.

Decided to take a look at the service manual CD and found the troubleshooting procedure for those trouble codes. Without copying the entire procedure in this post, it led to only two other possibilities - BAD PCM or a problem with the wiring. Considering my truck has only 54,000 miles on it I highly doubted it would be the wiring and also realized that I wouldn't be able to do anything to troubleshoot the PCM. So I reluctantly took my truck to the dealer.

Dealer said my PCM was bad (burned out O2 heaters). They ordered a new one and installed it last week. Unfortunately, the light came on again, got it scanned and came up with the same codes. Took it back to the dealer today and they were stumped, and mentioned it could be in the wiring but their is no way to tell without incurring more time. Not wanting to incur their hourly rate quite yet I made another appointment a couple weeks away, while I try to figure it out.

Has anybody had a similar problem? Any easy ways to check the wiring? - The passenger side connector is awful hard to reach from under the vehicle. Any help at all is greatly appreciated!

 

Welcome to the forum

The only thing that I can think of right off is to make sure that the wire hasn't rubbed thru on the frame or has layed on the exhaust manifold and melted together.
Jimmy

 

Which o2 sensors did you replace?