hi guys, truck still idling super rough. got a scanner, but don't understand some of the codes. this is what came up.

31 - chilton says PFE, EVP, or EVR - code manual says EGR sensor or EVAP control system low voltage - i ordered a EGR sensor/will install tommorrow

21 - chilton says ECT out of self test range - manual says cooling temp sensor - i replaced coolant temp sensor

40 - can't find this listed anywhere

31 - again ?

35 - chilton says PFE or EVP circuit above closed limit - manual says no EGE position signal RPM low or EVAP control system fault - no idea what this means

41 - chilton says HEGO sensor circuit indicates lean or no HEGO switching detected - manual says HEGO (HO2S) sensor low/system lean - i don't lnow what this means

PLEASE HELP I'M HAVING TROUBL FIGURING OUT WHAT ALL THIS MEANS

 

If you have a coolant sensor that is bad the engine may be not be switching from open loop (cold engine - engine runs on predeterimened program - no sensors input used) to closed loop (engine uses input from sensors). That may be why the oxigen sensor fault is coming up. Keep track of the codes you now have. Make the changes - replace the senors and such - clear the codes and see which one come back after the repairs.

 

After changing the sensors, if you still have sensor error codes, you need to measure the wires at the sensors and see if you have 5 volts there. You may have a wiring problem.

 

HEY GUYS,
replaced thermostat and engine coollant temp sensor.ran the truck 15-20 min was still idling rough. let it sit a couple of hours and then it ran much better. pulled the codes again and got 11 - 10 - 21c. am i correct to believe this means system OK and that 21 was the last code tripped?

 

It's been a while since I've messed with mine. If I remember right 11 means the system passed. Are these codes with the engine off key on or with the engine running?

If you are still getting the coolant sensor fault check your wiring, connections and reference voltage going to the sensor.

Did you clear the codes after putting on the new sensors? Was the engine warmed up when you tested it?

 

engine was warm at retest, but i did not clear the codes