Just woundering.... Is there a difference between getting codes yourself and the dealer getting codes for you? Ford replaced my bad Map sensor. They also replaced the IAC gasket, because of a vacuum leak. I dont know if they replaced the IAC gasket before reading for trouble codes. Why did I get codes for EVP and EGR, codes 31 and 33? Will a bad Map and a IAC vacuum leak cause these codes?

I got these codes while running on the rear fuel tank.

12 IAC
13 IAC
31 EVP
33 EGR

I got these codes while engine was hot and not running

22 Map Sensor
33 EGR

Thanks guys,
Mike

 

The dealer gets the same codes you do, just quicker if they have a certain kind of tester. The MAP and IAC vacuum leak should not cause the EGR codes.

 

Code 12 and 13 could be provoked by vacuum leaks and/or a bad MAP.

They mean that the ECM, using the IAC alone, couldn't get the RPM fast enough (12) or slow enough (13). If too much air is coming from somewhere else (a bad leak), then the IAC has insufficient influence on the air entering the engine, and thus the idle RPM.

If any issues with the MAP cause an unstable idle, then it is very difficuly for the computer to get the kind of steady-state behavior it likes to see to get a pass on codes 12 and 13.

Codes 33 and 31 is unlikely to be caused by a vacuum leak, unless the plumbing to the EGR valve is what is leaking, and it is leaking so badly that there is not enough vacuum left to work the diaphragm and open the valve valve.

Code 33 is not listed as a valid KOEO code -- it is KOER or continuous memory only.

Typical dealer behavior is likely to be to pull the KOEO codes first. If any of them show up, they are reported and any continuous memory codes ignored. So that's probably why the dealer only reported code 22 to you.