Does anyone have any experience with this code? it reads out EGR sensor A circuit High. What does it mean? What can be done to correct it? Thanks alot guys

I'm not 100% on the EGR but it could be stuck.





I hear the way to deal with it is to take the lower intake off and replace it with the "F" engine gasket and then block off the EGR with a shim and plug the vac line.

Pfloyd update your sig so I know what yr & stuff you have, home for lunch rite now, gotta go back, will check my book when I get back home.

it should pop up, but its a 96 tahoe

PM me your fax no, I have a 98 manual that should be close, here are the words


A EGR control pressure/baro sensor is used to monitor the vac in the EGR circuit, It senses actual vac in EGR vac line and sends sig to PCM. This sig is used to control EGR duty cycle calculated by duty cycle calcd by PCM. This is a type B DTC.


PCM checks this continiously when IGN is on.


DTC is setwhen EGR control press signal is greater than 3.96v (85kPa) > 2 sec.


PCM shuts down EGR, ilum the MIL on 2nd consecutive drive trip the diagnostic fails.


With IGN on and engine off, manifold press =to atmospheric with sig volt being hi. This info used by PCM as indicator of vehicle altitude, the Adaptive Learn atrix is used to adjust vac control based on Mass Air Flow.


ALM may change as result of backpressure increases over life of vehicle or other engine system variation,.


What does all that above mean, PCM regulates EGR by varying vac via pulse width modulation of EGR vent solenoid to supply side of EGR sol, baro sensor on firewall teed into EGR sol. outlet to know how much vac is available to EGR. Baro at start up vs vac on EGR is feedback to PCM of EGR position. PCM using EGR poss vs load(mm 3) vs MAF and ALM hi or low determines if EGR functioning properly.


Three solenoids in row front to back WG, EGR Vent (pwm) ,and EGR, mechanical leak on any of those vac insufficient will set code. Problem with EGR vent-EGR sol-firewall baro sensor most probable cause of EGR problem, leaking EGR valve diphragm, another possibility.


least likely but possible plugged cat-EGR manifold-MAF or PCM but should have other codes with those as well as P0406.

does anyone have a procedure for disabling the EGR function? Id be interested in just getting rid of it all together. Thanks alot

Now this is for off road puropses only, all that is required is to place a 18 ga sheet metal shim under the EGR valve body, but it wont fix your code problems, as I suspect one of your inputs to the PCM is in error, only way to make it go away completely is a reflash so the PCM does not look for EGR feedback signals.


Yes plugging the hose will do the same but I have found with a weak EGR valve spring, and "getting on it" the valve can be lifted off its seat I block mine off when offroading so that mechanically is impossible.

pull the intake manifold and install HD gaskets, now your EGR will still appear to funtion normally, but there will be no exhaust flow to it so it won't affect anything. also eliminates problems with exhaust leaking into the intake, and keeps it looking fully legal.

i achieved this and some performance when i swapped my "s" upper and lower manifolds for "f" styles. still provided me with a flat area to mount the egr but no hole undernieth and no xtra obstructions in the intake path