have a 99' 5.2 and i have been getting the codes p0141 and p0138
i think the p0138 is the pre cat and the p0141 is a relay? 1/2 so bank 1 sensor 2 with the p0141 i think i just want to make sure

 

this is bank 1 sensor 2, so post cat

and this is also the post cat sensor, just the relay, replace the relay, reset the computer and see if it comes back, my guess is that it will not.

 

http://www.obd-codes.com/p0138

had the p0138 a year and a half ago...replaced it with a denso and problem went away just in time for emissions.

 

ok thanks ill try and get a replacement relay and see if that clears it, ill prob get to it monday and ill post back

 

btw can i get this at an suto parts store or should i go to a dealer to get the relay. also when i replace the relay might this solve the p0138 as well?

 

you should be able to get the relay at any auto store. yes it may solve both issues (reset the PCM/clear codes after installing the relay)


if the p0138 comes back you will need to get a new post cat o2 sensor

 

+1. As for the sensor your best bet is to get a denso sensor online or at the dealer. Auto parts stores may have the densos but most will try to sell you the bosch.

 

i looked for the relay today and its not in the fuse box. my buddy had a 01 and its in there i guess the 99's have it somewhere else. looks like i will get the o2 sensor instead

 

Looks like it might be powered with the ASD relay. Swap the relay with one of the same number.

If you need O2 sensors then go to www.rockauto.com because they have the best deal on Desno O2 sensors, and search for a coupon for 5% off. I would only buy Desno or NTK sensors.

 

ill check it tomorrow