99 S70 Base - P0172, P0171 and P0174

Post by **E Showell** » 08 May 2015, 15:04

Replaced ECT and T-stat. Went for 14 mile test drive. No CEL, no codes so far. Cooling fan did not run on after engine shut-off, although in fairness, it hasn't done that every time out.

I'm thinking, and hoping, that I've got this licked.

Post by **E Showell** » 09 May 2015, 11:30

We'll we can rule out the ECT and thermostat. Turns out a 16 mile test drive would have been the ticket. Now I'll swap in a known good MAF and see how I do with that.

Post by **precopster** » 09 May 2015, 11:46

I need to know if cooling fan stays on after shut down. All my cars have done this and I feel it's a normal function of the system if coolant temp is over a pre-determined value after shut down. It was designed to minimise coolant hot spots which may weaken the (plastic) radiator.

Did you try the battery reset?

Post by **E Showell** » 09 May 2015, 13:27

Mike. Haven't done battery reset yet. That and swapping in known good MAF are next.

UPDATE -- can't swap in known good MAF. Attachment bolts stripped and can't get the good one out. Headed for the PNP on Tuesday to harvest a MAF or two along with other assorted goodies.

Post by **abscate** » 10 May 2015, 02:39

E Showell wrote:I was doing some reading on another Volvo forum -- I know, the shame -- and ran into a post by a guy who had ETM issues and theorized that a bad ETM can take down a good MAF and that, indeed, an otherwise good MAF would likely fail very shortly after the ETM failed.

I'm pretty sure the MAF is an input only device ( that is, it just gives inputs to the ECU). I have no idea how a device that is input only can be taken out by the ETM. Sounds like the other guys need to back off the crack pipe....

Post by **E Showell** » 10 May 2015, 03:57

I'be driven about a dozen miles since disconnecting both battery terminals and touching them together, then leaving the battery disconnected for a half hour. So far, no CEL and no codes pending. I'.'ve got about 100 miles to drive today. I''ll report back tonight.

Post by **abscate** » 10 May 2015, 07:06

Thats with the swapped MAF, right? Hope that nails it.

I just got my NY Inspection in the 100 miles between clearing the P1138 code, and the 50 miles I need to reset all the monitors. Its good to beat the man. Next time I win a slip and fall case, Ill spring for a new/used CVVT to put this one to bed. I cleaned it and it went from faulting right away, to going somewhere between 100-2000 miles before it faults. Maybe try cleaning one more time.

140 USD new
30-60 used

Post by **precopster** » 11 May 2015, 01:15

Same MAF is on the car. As far as I understand it's just a battery reset so far.

Steve this is a Denso MAF. There are no $140 ones unless you'd like to point me to that generous seller's link

Post by **E Showell** » 11 May 2015, 04:36

Mike is correct. Just a battery reset so far. Drove c. 80+ miles yesterday and CEL is back. Haven't read codes yet, but I am betting PO172. I'll post after I read the codes later this morning.

Post by **E Showell** » 11 May 2015, 07:00

Latest code was P0455 gross evap system leak. I removed and retightened the gas cap and am assuming that may take care of it. Gas jockey was in a hurry at last fill up and I'm betting he did not secure the cap properly.

99 S70 Base - P0172, P0171 and P0174

Re: 99 S70 Base - P0172, P0171 and P0174