i decided to read codes on my 96 bronco and came up with p0420 and p1401. what should i do now?

 

Code p0420: Catalyst System Efficiency Below Threshold (Bank 1) indicates that the readings received by the THIRD O2 sensor (downstream of the catalytic converter) showed less oxygen than acceptable. The short answer is that the catalytic converter is failing either because it is clogged or the substrate has deteriorated to a point where the unit is simply not functioning well enough.

Code p1401: indicates that the voltage received from the EVP (EGR Valve Position) sensor was higher than expected. This means that the EVP sensor is allowing more voltage than it should back to the computer. The short answer is that the sensor should be replaced. It is mounted atop the EGR valve on the passenger side of the engine. It has a 3-wire connector.

To troubleshoot the EVP sensor, apply vacuum to the valve manually and release it slowly. You should be able to connect a meter to the center and left-hand pin of the sensor and (with the meter set to read resistance) watch it slowly decrease resistance as the vacuum is released. However, even with no vacuum applied, there should still be some resistance. The meter should never drop to zero.

 

i dont have anything on top of the egr valve, is there somewhere else i should look for it? or does my truck use a dpfe sensor instead? i've done alot of reading and looking at pics but i'm kinda confused at this point.
thanks for the info greystreak.

 

Oh hell, yeah, no EVP on a '96. DPFE sensor but I cannot recall the test procedure for it right now to save my soul. I'll see if I can find the info. I'm stuck at work right now and the Rockettes are still rehearsing so it'll be a late night.

 

ohh, Rockettes, sounds like fun! anyway, i replaced the dpfe sensor today and the truck runs alot better and gets 3mpg more now according to the SG2. i cleared the codes again and have'nt had any come up yet but i only drove for 9 miles so far. i'll see tomorrow morning on the way to work, it's a 30 mile drive. maybe the egr malfunction caused the o2 sensor code, who knows.
thanks for all the help

 

Yeah, they (Rockettes) are here until the 17th of November... glad the sensor replacement helped. By the time you make that 30 mile drive, the ECM should have "relearned" the operational parameters of the system.

 

all is well but i came up with a p0320 code. what should i look for?

 

If the truck starts and runs clear all codes and run the test again. p0320 is an ignition fault Code that triggers under initial startup misfire conditions. Basically means that there was a misfire at some point since the last time Code memory was cleared. If the truck runs fine and idles properly, you shouldn't need to worry about it.

 

yup starts and runs great but, i've had an intermitent belt squeal that i can't figure out. i think i've narrowed it down to the smog pump because when it starts squealing the smog pump pulley slows down while the other pullies spin the same. doe's it sound like i'm on the right track or am i pissin in the wind here? thanks for all the help, you really know your chit bout these broncos.

 

If you can actually observe the smog pulley slowing, you're probably on the right track. The drawback is that there really is no repairing a smog pump that seizes.