Yet Another ETM Thread

gspences · Post by **gspences** » 26 Dec 2017, 20:23

Subj - 2001 XC70 throwing PO102 code.

Been troubleshooting my "new" XC70 for awhile, working through the ETM flowchart provided by XEMODEX. Bottom Line - I earlier replaced the MAF with no resolution ... long story short, just bolted on the XEMODEX ETM today. The car at least runs now (before no idle at all and zero throttle response) but it's a tremendously rough idle. I've read other posts and all the XEMODEX literature ... my fuses are all good, vacuum hoses good, new gaskets for intake manifold & ETM ... and the ETM ain't bolted on backwards.

Now I'm wondering now about that Engine Management Relay ... it's on the XEMODEX flowchart as a potential problem but I'm not seeing the myriad codes on that flowchart. Still ... with a new MAF & ETM, might that relay be the problem? If so can I work with an Autozone relay or is that a critical OEM part?

Appreciate any further guidance. Just not sure how to troubleshoot further after seemingly replacing all the expected problem parts.

Post by **E Showell** » 26 Dec 2017, 20:37

Plugs, coil packs?

gspences · Post by **gspences** » 26 Dec 2017, 20:41

Plugs are new ... haven't messed w/ the coil packs.

Other background - the car was running great one day ... then the next day it wasn't. In hindsight I might not have NEEDED some of the things I've replaced, but since I know nothing of the car's history I went ahead w/ the MAF/ETM replacement. Also just did the PVC service while I had the intake off.

Post by **E Showell** » 27 Dec 2017, 05:59

Total mileage?

gspences · Post by **gspences** » 27 Dec 2017, 06:40

Mileage is at 225K.

gspences · Post by **gspences** » 27 Dec 2017, 06:52

I shouldn't state "I know nothing" of the car's history, because a mechanic friend who services Volvos sold it to me. He'd done some work on the vehicle over the last year or so, mostly minor maintenance, repair of the AC, timing belt replacement, and other gremlins that pop up on these cars. Not sure if he touched the coil packs or when they were last replaced. He said the previous owners were a couple who had been meticulous about the maintenance. But all he'd done to the throttle was a cleaning, and had had no need to service the MAF. I only put about 500 miles on the car before it started acting up. This mechanic is trying hard to retire now so I'm trying to get this running without running it over to his shop.

Post by **E Showell** » 27 Dec 2017, 07:44

If coil packs are original to car, they are about 125k past their sell by date.

gspences · Post by **gspences** » 27 Dec 2017, 07:55

OK - I'll look into that, as I'm trying to take care of any overdue maintenance; i.e. PCV as mentioned above.

I'm obviously no experienced mechanic but I don't see the connection between my problem (a very sudden onset of throttle & idling problem) with the coil pack. Do all coil packs fail, simultaneously, where the car will run beautifully one day and the next it won't? I came here for advice so I appreciate what you're offering, I'm just not understanding the connection to the PO102 code. Any thoughts on the Engine Management Relay? I've read elsewhere that this relay controls a myriad of aspects that could trigger the PO102 and cause symptoms similar to ETM/MAF failure.

Post by **abscate** » 27 Dec 2017, 09:03

When running is rough, codes are about 50% reliable as to guidance. Diagnosis by symptom is rarely successful on the 1999- cars, especially of unknown care.

At 225k the issues to understand before you five in are compression, plug evaluation, Fuel pressure, ETM history ( date code?)

It's likely you have 3-4 things out of spec that you will need to address, not a golden bullet.

gspences · Post by **gspences** » 27 Dec 2017, 10:01

abscate - thanks for that ... and yes, I recognize that golden bullets are always nice

That said, when a vehicle very suddenly changes from running like a top to having no throttle response, I figured I was looking at a likely electrical/signal issue. Given the frequency of ETM/MAF problems I started there first ... now that those are eliminated as potential problems I'm just seeking the next step. (Note that ETM/MAF & plugs have all been replaced ... that's several things from your list.) The Xemodex flowchart seemed to suggest the Engine Management Relay as a possibility. But ... sure ... maybe I need to look into fuel pressure, compression & coil packs; still, I'm not understanding how something out of spec would cause the car to run fine one minute and not run at all the next.