S/V/C Rough Idle - P1175 / P1238 / P455

[boisebricks]

My 1999 V70 Turbo w/ 162k on it is having some intermittent rough idling. It is consistently throwing a P1175 / P1238 / P0455 code combo. I've read where the P1175 is the idle control valve, but the 99 v70 doesn't have the ICV. I'm thinking maybe the PCV or the Throttle control? Anybody have any experience with these codes or the combo of them? Thanks!

 

[CEHepp]

I can't do much with those codes.

When is the last time you cleaned your throttle?

You could also have a faulty MAF sensor. When it starts to run bad, unplug the MAF sensor. This is a basic test but it will put the ECM into calculated airflow mode and could eliminate the MAF sensor as the culprit.

 

[professor245]

It's probably ETM, Since Denso MAF's almost never go bad (I know lol) but it will throw an MAF code cause of ETM, clean the throttle body.

As explained here

http://forums.turbobricks.com/showthread.php?t=287699

 

[boisebricks]

so i went to dig into this over the weekend, thinking that it might be the ETM, or maybe the PCV, and who knows what else could be causing the issue... So i pulled the Injectors, fuel rail, intake manifold, fan & shroud, hoses, blah blah... ETM looked very clean - i thought there would be some carbon buildup, but there was none. I had a PCV to put in so i replaced that while i had all the parts out and access. Numerous vacuum lines and coolant lines replaced and everything put back together. I've got 30 miles under the repair and no error codes. I'm thinking if they do come back, then a ECU replacement?

I suspected maybe bad MAF, but when it was stumbling, i disconnected the MAF to see if that helped out and it had no effect...

 

[CEHepp]

It's probably ETM, Since Denso MAF's almost never go bad (I know lol) but it will throw an MAF code cause of ETM, clean the throttle body.

As explained here

http://forums.turbobricks.com/showthread.php?t=287699

Turbo cars have Bosch MAFs.

 

[professor245]

Missed that it was a turbo...But still has Magneti Marelly ETM, that thing really knows how to give you s**t...

 

[gsellstr]

P1175 is long term fuel trim, ECM260A.
P1238 is Turbocharger control system flow fault, ECM6806
P0455 is Leak diagnostic, ECM4308

Sounds like all 3 lead to a vacuum leak. Fresh hoses to everything very well may address it.

 

[boisebricks]

i certainly hope so. day 3 of no codes... so far so good...