GMC Suburban with CEL code P0430 , slight rough idle -- AFTER charging a/c ???

Hi

downloaded test results from scan tool. here's the file:

formatting link
recently, had a/c serviced. when picked it up, it had this code (didnt have it before took in.)

the a/c shop siad that6 compressor wasnt running because a/c/ system empty. so, they injected dye, leak tested it with a light , found no leaks, and recharged the system. when i picked up the truck (via lockout and 2nd key), truck had CEL.

P0430 , and the test results in the file.

i dont know what recharging the a/c would have to do with inefficiency in the 2nd bank, but maybe just a coincidence??

what to check ?

best regards stu

Reply to
Stu Weber via CarKB.com
Loading thread data ...

sorry- that xml link wont work for some. try this one?

formatting link
thanks

Reply to
Stu Weber via CarKB.com

Can't open either link. P0430 is TWC efficiency bank 2. If you have a scanner check the O2 sensors and compare bank 1 to two. Also look at misfires on the cylinders since you get a rough idle. They may have disturbed a plug lead or something in the bank two area or moved a plug wire against the exhaust. I don't know for sure but bank 2 may be the side the A/C lines and compressor are on.......

Reply to
Woody

sorry about that- didnt know what to do with that xml file. wish i could convert it- ill try

i did manage to get the voltage graphs for B2S1 and B2S2 going for a bit on my scan program. The white line of S1 varies up and down, while the yellow line of S2 stays down alomost flat. when tapping the pedal, the yellow line approximates the pattern of the white line. but, B1S1 and B1S2 behave the same way. the knock sensor is at 95%, no misfires in any cylinder. on the test page of the program, the EVAP excess vacuum test 1 is almost at a hair below max value as is the EVAP weak vacuum fail test 1 and the EGR deceleration test.

Reply to
Stu Weber via CarKB.com

Have you reset the code and see if it returns. If not it is possible something happened when they worked on it temporarily. If they disconnected the battery or reset the computer it could take several drive cycles to relearn the computer and set the test cycles. Some roughness at idle could be because of this and should go away with drive cycles.....

Reply to
Woody

well i cleared the code, abd it hasnt come back, but the idle is still a little rough. also, while driving, i see the EGR functioning on a graph, but the truck's tests still have the same errors, a failed egr deceleration test, and the vacuum tests mentioned above.

is there a hose or vacuum regulator somewhere i need to check?

Reply to
Stu Weber via CarKB.com

Reply to
Shep

i shoudl mention that we recently has the a/c serviced. he said the system was empty, so he charged it and looked for leaks. i know some of this stuff is near the compressor, but a differnt system. what could he have knwokced loose, etc etc?

Reply to
Stu Weber via CarKB.com

Reply to
Shep

Shep, did that. didnt see anyting loose. actually touched the hoses and connections from the EVAP ssyste. nothing seems loose or cracked. dont know what to check next

Reply to
Stu Weber via CarKB.com

another piece- we've had this code about 2 weeks.

2 weeks before that, the fuel pump was replaced. i KNOW the EVAP system is hooked into that somewhere- could be a loose connection in that job (shop did)?
Reply to
Stu Weber via CarKB.com

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