1999 C70 P1171 then P0236 and P0237 aft radiator replace

Post by **Kazthebassman** » 20 Jun 2015, 10:49

1999 C70 cabriolet 2.4 T5 automatic
I replaced the radiator a little more than a month ago.
Afterwards, the car seems lack power and to have possibly have lost some of the turbo boost.
I inspected what vacuum lines that I could find. They are not in great shape but seemingly ok to the eye.
A p1171 code appeared. I cleaned the MAF, changed spark plugs, fuel filter and air filter. It was about time for my scheduled 'tune up' anyway. There was an improvement but the P1171 code appeared again, in about 80 miles of driving. Then it would not stay cleared.
Yesterday(a month later), the car had symptoms of throttle position issues..(IE: hunting, surging.)
The codes I pulled are :
P1171(LFT),
P0236(Turbor Super Boost Sensor A CKT Range/Perf) and
P0237 (Turbo Super Boost Sensor A Circuit Low Input).
When I replaced the radiator, I left the fan in place. I am wondering if the intercooler may have acquired a small hole while squeezing it into place. Does this seem like it may be indicative of the ensuing symptoms and codes after the radiator replacement?
I did not remove any vacuum lines during the radiator replacement.
Could there be a vacuum line that I may have inadvertently knocked off or damaged during the radiator replacement?
As many of us know on these aging Volvos, it can be one problem after another or even one problem during another.
Do you think these codes are related or maybe I am having several issues?
From what I have read (and some experience) The P1171 is usually MAF related.
The P0236 and P0237 can be (turbo control valve- TCV) or maybe other things.
The 'hunting/ surging is indicative of the TPS, ETM.
NOTEs: The intercooler and radiator inlets where not plugged, while I waited a week for my radiator to arrive. I do not know if moisture or pollen could have some how entered the system. The hood was closed.
Also, there was no overheating.
Any suggestions would be most welcome. Thanks, Kaz

Post by **Kazthebassman** » 20 Jun 2015, 10:52

Another note: I did an oil change and filled to the top of the hash marks(not over) the day before the throttle issues occurred.

Post by **abscate** » 21 Jun 2015, 04:39

Almost certainly bad vacuum lines and probably related to bumping or stretching them during the radiator job.

The two 023X codes could be a bad MAP ( not MAF) sensor on the ELectronic throttle body. That's another place which gets banged around during radiator swaps. Best diagnosis for MAFs is a scan tool that reads airflow

Post by **Kazthebassman** » 25 Jun 2015, 20:47

Great advise Abscate, and much thanks.
I replaced the 2 MAP sensors.I found a nice deal on the 2 used. I changed a few more vac tubes. P0236 and P0237 are gone.
The P1176 came back.
I bought the harbor freight vac pump/gauge and pumped it up to 25 inhg on the turbo waste gate. The arm did not move.
Do you think that is enough vacuum? It runs ok til you give it some heavier throttle. Sounds like you can hear the turbine banging a bit when you do throttle it. Any idea if this may have caused my sensor problem or vice versa? Thanks

Post by **Kazthebassman** » 25 Jun 2015, 21:06

I just found out it's pressure, not vacuum that actuates it...I'll try that tomorrow.

Post by **abscate** » 25 Jun 2015, 23:34

I actually have the IPD turbo pressure gauge kit and might be through NJ in a couple weeks. Let's stay in touch. In MUC at moment

Post by **Kazthebassman** » 27 Jun 2015, 13:13

I tested the waste gate properly and it moves nicely.
I then proceeded to pressure test the rest of the turbo system with compressor at 10 psi, clamps and bags and such.
I heard a hissing at the bottom of the intercooler. I thought eureka ! I must have cracked something during my radiator replacement. I found an intercooler local, in nice shape at a nice price.. I thought this is all going very well. I pressure tested that intercooler....hissing out of a weep hole in the bottom. I researched the net some more. It seems this may be normal.
After I get my intercooler out of the car...the same hissing through the weep hole. There are no other leaks in my present intercooler. Now I have to put it all back together again.
I guess I'll try a new MAF sensor next. It only runs slightly worse with it removed. It runs pretty decent til I hit the gas a bit. Maybe at +2000 rpms. Absate, I'm in North Brunswick NJ. I hope to have this remedied before your NJ trip but yes let's stay in touch.

Post by **abscate** » 02 Jul 2015, 16:55

The weep hole is normal. It's really easy to have a loose induction clamp in a turbo which will make you think your engine is toast

bansheelos · Post by **bansheelos** » 06 Nov 2015, 13:49

Kazthebassman wrote:I tested the waste gate properly and it moves nicely.
I then proceeded to pressure test the rest of the turbo system with compressor at 10 psi, clamps and bags and such.
I heard a hissing at the bottom of the intercooler. I thought eureka ! I must have cracked something during my radiator replacement. I found an intercooler local, in nice shape at a nice price.. I thought this is all going very well. I pressure tested that intercooler....hissing out of a weep hole in the bottom. I researched the net some more. It seems this may be normal.
After I get my intercooler out of the car...the same hissing through the weep hole. There are no other leaks in my present intercooler. Now I have to put it all back together again.
I guess I'll try a new MAF sensor next. It only runs slightly worse with it removed. It runs pretty decent til I hit the gas a bit. Maybe at +2000 rpms. Absate, I'm in North Brunswick NJ. I hope to have this remedied before your NJ trip but yes let's stay in touch.

Any luck? I'm located in Bergenfield NJ.

Post by **Kazthebassman** » 25 Nov 2015, 13:29

I put in a used MAF. That seemed to fix it.I also put in a new turbo boost control. I believe it was the sensors MAPs and MAFs. Cleaning the MAF wasn't enough that time. I think I may have fouled things up by putting in some old fuel additive.
My latest issue is https://www.matthewsvolvosite.com/forums ... =1&t=73201
this new issue came a couple months later.