S60 Engine Surge, "Engine Service Required" TEXT

[BobbyC]

2001 S60 T5 Auto Trans 104,000mi

I am experiencing surging/hesitation on light acceleration, and to a minor extent during cruise. At times it feels like the throttle is being cycled w/o my input.

The idle is very smooth and consistent, however. I would remove and clean the throttle body unit and clean it, but usually an inconsistent idle is the first signal that a cleaning is needed, and I don't have that.

The surge/hesitation is much worse w/ the Air Conditioning on.

The Cruise Control is intermittant. The switch will often not make the "CRUISE: light illuminate in the speedo window, though when it will, the cruise control works fine, but usually quits in a few minutes. Sometimes re-starting the car will allow the cruise control to function again. Not sure if this is related to the condition.

There is NO "MIL" or "Check Engine Light" illuminated, though most of the time I get a yellow triangle warning, and a text message "Engine Service Required" (I believe it says). It sometimes goes out, though surge is still there.

I have not yet had my car go into the "Limp Home Mode" as have many owners with the warning apparently have.

I hooked up a Equus Innova 3100 OBD II Code Scanner to the car, and it is evidently not communicating with the ECM properly, because I get the "Run Monitor," but it ONLY shows the CC (Catalytic Converter) monitor, and none
of the other ones displayed or are blinking. I also do NOT get the "DONE" message which is supposed to tell the operator that the scan is complete. It shows "00" for Codes, which would indicate that there are NO codes storred, though without the "DONE" I have my doubts. The scanner works fine with other vehicles I use it on, BTW, including other (older) Volvos.

I know there is a silent recall, of "campaign" for the ETM (Electronic Throttle Module) on the car (National Highway Traffic Safety Administration #06V441000), extending the warranty to 200,000 or 10 years, but am not sure if this is my problem. MOST 2001/2002 Italian Marelli ETMs have, or will go bad according to what I read.

I welcome any advice or counsel regarding this problem.

My closest Volvo dealer is 1.5 hours drive time away, so I'd like to be prepared when I visit.

Thanks,
Bob

[randyman]

I experienced similar surging on my S60. No codes. Plugs were not more than a year old, so I pulled all the coils and tested them with my multimeter. 4 tested the same resistance on the primary and secondary sides. 1 had a very high reading compared to the others. I replaced it and never had a surge since.

[BobbyC]

Interesting.

From the service records on the car I have, the spark plugs and ALL of the coils have already been replaced less than 10,000mi ago. They were re-newed at 94,000mi, and the car is at 104,000mi.

Curious...Was your idle super smooth like mine is?

Also under heavy throttle, I have no miss. The car really does get up and go smoothly under heavy throttle.

It's under light throttle it surges (badly w/ the A/C running).

The surging is much worse after the engine was hot, shut down, then re-started after a few minutes (as one does when after shopping at a store).

Did you have any hard miss under any conditions?

Bob

[randyman]

I had the surge while asending hills and such, my A/C is on most of the time. The more "load" on the engine, the more likely the surge will appear. The ignition system and the fuel system (lean conditions) will cause your problem. It doesn't take long to perform the check I suggested. I would start there first. My experience is, just because the electrical parts are new doesn't mean their good today. A good analagy is a light bulb. A new one could go bad for any reason a week after install. Low fuel pressure from a worn pump or restricted fuel filter would be another place to investigate.

[BobbyC]

Your point about the electrical parts is a good one (and I will do a primary and secondary check of the coils today), but with regard to the restricted fuel, if that were the case, the higher the demand for fuel, the worse the surge would be, until at some point, the fuel delivery could not match the engine's need for fuel, and the engine would literally starve for fuel. At that point, OBD II should start kicking out codes for misfires and fuel trim as the computer goes full rich trying to make the O2 sensor happy. Of course, a bad O2 sensor could cause surge, though again, it was also replaced less than 10,000mi ago (I know, that proves little).

In your case, you said the higher the load, the worse the surge, so fuel delivery could have been a cause. In my case, however, the higher the load (beyond steady-state and light acceleration) the more the load, the LESS the surge.

If I increase the throttle beyond maintaining speed, or beyond very gentle acceleration, the car accelerates very smoothly, and very strongly, with no noticeable surge and pins you to the back of the seat. I haven't driven above 100mph, but if I apply 3/4 or full throttle, 40mph to 100mph happens very fast. The T5 turbo is invisible during normal driving, but it apparently does make 257hp without fuss or fanfare when asked to do so.

If there were a shortage of fuel to the fuel rail, this would not be the case, because full throttle with full turbo boost demands a LOT of fuel compared to just maintaining speed, or gently accelerating. As the pressure at the fuel rail fell, the computer program could not keep the injectors open long enough (compensating for low fuel pressure) to keep the engine from lean-misfiring, and one would feel that condition, and (hopefully) the OBD II monitoring system would set a MIL.

I would like to know MORE about the "Engine Service Required" text warning I DO get. Does it set some code into memory that one cannot "see" with a generic OBD II scanner (like the Innova 3100 I used)? Will the dealer be able to see more than the codes one would see with a generic unit, and WHY did my scanner fail to see the Readiness Monitors? In that regard, I have enroute a more sophisticated scanner that has freeze frame and live stream data available ( http://tinyurl.com/3a7qv6q ) that may help with better identification of computer data. I will at least try that one after any other testing I do (like coil testing) before calling the stealer.

Bob

[randyman]

I would check the coils and if you find a bad one replace it, disconnect battery to clear the code if there is one in there. Then see what happens after driving. if coils seem OK then get it scanned with something better than what you have. The autoparts stores do it free.

[BobbyC]

I do plan to check both the plugs and coils this week despite their relative new age.

Yesterday I spoke with a Volvo dealership service manager about the problem, and he was not hopeful. Even if my ETM is bad, I should expect to sped close to $500 in pre-replacement diagnostic work and ETM cleaning at my expense before they would make the change later for free.

He said that even if the idle is dead smooth, and greater than light acceleration is normal, cleaning the ETM could cure the problem. He also said that there are a slew of sensors that may not throw a code (turbo sensors, throttle pedal position sensor, ...) that even their computer (I made the mistake of calling it a scanner, which insulted him) wouldn't show. It could take several hours and parts changes to find and fix the problem, in other words.

Same with cruise control.

My code reader is a Equus 3100, which is what the local parts stores use. I just purchased a better one, their top-of-line 3160 that will do freeze-frame, and live stream data capture ( http://tinyurl.com/2ef25ym ), but the Volvo tech said Volvo's system is made to be "proprietary" so only Volvo dealership computers will work well with it. That was confirmed by a friend in WA State who has an independent shop w/ a $6000 diagnostic/interactive tool that works with virtually everything, but sucks on Volvos.

[BlackV]

I’d really love to know what the solution was!