Need Advice: Stalling, "Missing", Power loss

[bornn]

Ladies and Gents,

I seek any advice or thoughts you may have on a problem with my XC.

I own a 2005 XC70 purchased new and meticulously maintained. 80,000 miles, all factory reccd service done under waranty and after waranty, done by me. I run synthetic and really try to take care of the car.

About 2-3 months ago my wife and mother were driving the car at road speed and experienced a loss of power and hesitating. It occurred again about a week later for my mother and father in the car and this time resulted in a loss of power, hesitating, and finally a stall when reaching a traffic light. The first occurrence was after the car was warm, about 20 minutes into a drive. The second instance was just after start on a somewhat colder day.

Since these two occurrences, I have had it happen to me while driving. One of the times it occurred twice after the car was warmed up and at driving speed. The car started to lose power, RPMs dropped, I feathered the accelerator to try and keep it running, and after stopping the foot action it stalled on the side of the road. Turned the ignition all the way off, restarted, continued on and it happened a second time. Same symptoms. I did the same actions, and drove it to the destination with a few more momentary blips of problem. Shut it off. Drove it home a few hours later with no issues.

In addition to the engine related issue, I have also had the Starter Immobilizer issue "Start Prohibited Try Again". Usually clears by turning ignition off and back on again.

Here is what I have done so far and the results:

I had my Volvo Mechanic pull the error codes off the car and he came up with ECM710B Immobilizer Comm Missing, ECM291D Fuel Pump Control Module signal too low, ECM291B Fuel Pump Control Module Signal Missing, CEM9C03 antenna light ring signal missing, CEM6c49 Transponder comm faulty signal, CEM6c48 transponder type faulty signal.

I took the car to my local Volvo dealer and had the complimentary software updates done on the car. Volvo tech journal references a software bug for causing the start immobilizer problem. I also hoped the software would fix the power loss and stalling problem.

After the software flash both problems resurfaced. The Start Immobilizer issue would come up after sitting in a parking lot with the ignition in position one listening to the radio and then going right into a start-up from that position. I would turn the key all the way off and start normally on the second try.

The power loss continued to occur at random intervals. Sometimes the car seemed to idle rough, sometimes it would almost "miss/stall" for a momentary second while driving.

After talking with the Volvo dealer mechanic who performed the software update, I decided to replace the Fuel Pump Control Module (PEM) per the Volvo 23-32 4/30/2008 Service Bulletin which replaces the module underneath the car with a new one located near the spare tire in the rear compartment as I felt this was likely the culprit of the problem. His advice right after doing the software flash was to see if the new software fixes the issue, and if not, consider doing the control module for the fuel pump. The original factory part was mounted underneath the car and exposed to moisture, temperatures, etc. It was a straight forward job and I had no problems completing it.

Last night I drove the car after making the PEM replacement and for the outbound trip, it ran flawlessly. Coming back, the same hesitating, power loss, momentary "missing" happened again. (Back to the drawing board!) My father and I own two Volvo XCs, his a 2006. We discussed the problem and researched more this morning and read a bunch on all of the Electronic Throttle Module issues with the early 2000 Volvos. I had asked the dealer about this during my visit, but he told me, in his experience, my model year did not suffer from these problems. Still, after reading a bunch of kindly published information, I had a hunch that the ETM or Mass Air Flow Meter MAF was a likely culprit. Neither of these seem to throw off or generate error codes either!

To trouble shoot the MAF, we switched MAFs between our cars this morning (same identical part) and went out for a two ship test drive. Sadly I was still able to duplicate my power problems by coasting for a bit and then coming hard on to the accelerator. The car would momentarily jerk or lose power during the acceleration. It was also idling rough which was noticeable on the RPM gauge and by listening to the muffler.

Next, I went ahead a garaged the car and took off the ETM and cleaned it thoroughly with carb cleaner and a tooth brush. I had read about dealers performing this work as a potential fix. Most of the authors seemed pretty skeptical.... After the replacement of the cleaned ETM (which was dirty), the car is still idling a bit rough. It has not had the loss of power, stalling , or other symptoms yet, but realistically, I am waiting for it to happen. I am skeptical that the cleaning fixed the problem.

The only other data I can provide is that as part of the recent factory rccd maintenance work I did replace the plugs. I did not replace the plug wires, fuel filter, vac hoses, etc. as they "appeared" to be in good shape.

I am starting to be at a loss as to the cause of my loss of power issues. I am obviously hesitant to outright replace the ETM due to the cost. (It also burns me up that I can easily do the install myself but the dealer has to flash the software....)

Do you feel it could be related to the start inhibit, immobilizer problem? Could a lose antenna ring cause ignition cancel signals to be generated? the immobilizer issues never "shows" itself while the loss of power problem is occuring?

I have thought of vacuum leaks but felt those might be present full time, or at least every time a hard power input is made?

What would you do at this point? What other ideas do you have to check, perform, do?

Many thanks.

[Cyrus]

Ohm test the coil packs, they fall like dominos. When warmed up is when they start to show signs of failure. ( your car does not have wires)

[bornn]

Duhh! Yeah I guess I have cross pollination contamination on my brain from wrenching my pathfinder too! It has wires

I can ohm test the coils. I have not noticed before, but was under the assumption that the XC70 has one coil for all the plugs or does it have one for each plug?

What resistance number or range am I looking for?

[Cyrus]

One for each and call your local Autozone and see if your coil packs are listed in their test guide...this is where you will find the resistance numbers or perhaps one of the elders here have that info ready to post?

[Astro14]

I've had one coil fail - it was on the T-5, no. 2 or 3 - and it set the CEL, so I was able to narrow down the cylinder very easily. When I pulled the coil to check, it was obvious that it had failed since the oil from the transformer had leaked down the plug socket...I put a new one in, problem solved.

Is the CEL on?

[dpaton]

I would check those plugs gaps if it was me and my 05 seems to like only a few plug types (seems to be related to running 87 gas with ethanol and few other plugs types seem to be recommended with the turbo).

You can never go wrong with Volvo plugs but they are more $$$.

You can also purchase a single coil and cycle it through each spot.

Coil breakdown may not throw a CEL.

[MacNoob]

If this were my good ole Saab I would have the battery tested (old/weak battery can cause a host of wierd electrical problems) then think about a broken fuel pump. Longer shot would be a crank position sensor (don't know what the XC uses for that).

[bornn]

Hi guys. I have progressed further in my trouble shooting.

After cleaning the ETM the car did not show the problem again, however, I was skeptical, and worked on the car yesterday.

First I checked the battery at the engine hot post. With car turned off read right at 12 volts. With car running, read 13-14 showing alternator was charging. (As a side note, I always thought a good battery would be at around 12.2-12.4 at rest?)

As rccd, I removed and checked each coil with a voltmeter measuring Ohms. All coils checked out with uniform readings and no signs of cracking or damage. Pulled all the plugs (which were by the way Volvo OEM plugs I had replaced) and no signs of of wear, bad coloration, or not firing.

Next, I pulled and reseated every fuse that was applicable to engine/power operation. I also reseated all of the injector electronic plugs.

Next, I examined every vacuum hose, pipe, and connection in the engine with a mirror and light. Nothing.

Last, to trouble shoot a sensor, I swapped the Cam Shaft Sensor with my dad's XC.

Today driving the car, the trip out from home was normal. Coming back the problem resurfaced. No stalls, but while accelerating, the car will momentarily lose power and jerk. I found I can induce it every so often by coasting and then making a hard acceleration. ALSO, when the car jerks, I can instantly induce more jerks by pumping the accel pedal on and off. This will cause a series of jerks. Back in the garage at idle (to let the turbo cool) the car ran rough a couple of momentary instants.

I'm interested to hear your thoughts on the battery.

The remaining sensors I have not swapped to troubleshoot are the 1. crankshaft sensor 2. fuel pressure sensor.

I have not yet replaced the fuel filter but correct me if i'm wrong, but the symptoms don't really represent a clogged filter?

Does the car have a sensor/transmitter on the accel pedal?

I'm also wondering if anyone knows if its possible for me to swap the main computer (CEM?) with my dads XC without having to reflash software since both are already programmed? This would troubleshoot the computer.

At this point, I am still leaning towards the ETM being bad, a bad fuel pump, or something like a wire that is shorting or worn? Is there another intermediate boost pump for fuel?

Thanks for your thoughts. I'm still wanting to trouble shoot more items before I go to the dealer and "fix" or not fix the problem for mucho dollars.

[billr99]

Yep, a new 12V battery at rest should read closer to 12.6V. With the engine running, you should see 13.8 to 14.2V. Keep in mind that it is possible for a shorted or heavily sulphated battery to still show 12V but not have sufficient current to crank the engine and/or drive the electronics.

Cheers,

Bill

[TXC]

Hi all, new to forum, will post in the newbies bit later.

Ignore the battery voltage at the jumpstart points for now, go to the battery itself, thats where it matters, you may find a loose terminal if you're lucky and solve it in one check, give the terminal clamps there a good wriggle. (This could affect your immobiliser issue and hesitation)

Swapping batteries for a road test can't hurt either, seen many cars crippled by high internal resistance batteries.

Swap over or clean up (preferably swap) your crank sensor and road test again, this is most likely candidate for causing a complete stall/cut-out. Resistance checks won't really help you here, as your car runs as it is, not a valid test for this fault.

To rule in/out your ignition coils, number them up with correction fluid and swap them over with your donor car, one by one until thery're all swapped (time consuming but financially free). Also i.d the coils to they're original vehicle or else you'll get them mixed up. Resistance checks also invalid tests for these unless you have an obvious failure of one coil.

Misfiring/jerking on a sudden throttle load is a symptom of failing ignition components (I know, so is low fuel pressure, but lets start here).

Hope this helps.

Tone.