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Edward, ASE Certified Technician
Category: Volvo
Satisfied Customers: 3153
Experience:  I've had 10 years of experience on the car line at 2 Volvo dealerships, Quality level Volvo tech.
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2001 V70 T5: rough idle..coolant..idle, low rpm..coasting..low speeds

Customer Question

Can anyone help: 2001 V70 T5 rough idle, RPM surging, engine dying, coolant leaaking? What do I do next?


Hello Expert,


I have a 2001 V70 T5 with 160K miles in TX and have had problems recently with the car dying when at idle, low RPM and even when coasting at low speeds.  Please keep in mind I have very little mechanical knowledge or experience, but I know from past work I have had done that taking it to be a dealer/shop would be a total cash-i-ectamy on my wallet.

Local Mechanic told me to replace vacum lines which had hardened and cracked.  I replaced all the lines that looked bad visually. Still have problem.

Q1. Is there a link or instructions anywhere on how to check the system more thoroughly for vacum leaks?? (I think I should start here)

 I took it to dealer and after agreeing to a $120 diagnostic fee.  They will NEVER work on my car. Sounding somewhat amused they said “You have a lot wrong with this car, we can NOT diagnose it until you replace the PCV valve.  It will be $1,100, would you like us to replace it?"   I might as well have gone in pulled my pants down and bent over , that’s the feeling I got because I replaced the PCV valve myself which took me 4 hours and cost me around $130 in parts..(Dealer gave me wrong PCV valve which was bolted on the engine before I realized it was for the wrong car, so + 1-2 hrs scratching head and 2hr round trip back to dealer) Car still dying..

Looked online to see if I could find any solutions and suspected the MAF or ETM.

Auto Zone gave me these codes free of charge:

P0121 - Throttle pedal position

P0102 - Mass air flow sensor

I disconnected the Mass air flow sensor and found that my car was idling very rough still, with RMP fluctuating from(NNN) NNN-NNNNbut NOT dying with the MAF sensor disconnected.

Replaced Mass air flow sensor ($125 + 1hr labor), spark plugs($35), and wireless electrodes ($55) (spark plug boot' but not coils packs) Car was still idling very rough and was back to dying again.

Luckily, I thought to replace the fuel filter ($25 + .5 hrs) as well and found the old one clogged up, and barely dripping out dark brown fuel when flipped over.

I started the engine up and it was purring... The rough idle seemed to be gone, and the engine was not shaking and struggling as before.  Although engine was running more smoothly the RPMs were still fluctuating from(NNN) NNN-NNNNrpm. Took it on the road and found that check engine light, service light, and engine system service required message had disappeared. Then they reappeared about 10 miles later and the car is back to running very rough in low RPM and coasting at very low speeds.  It now feels like the car is jerking/surging forward when approaching a stop in sync with the fluctuating RPMs. The engine is dying less than before, but still has a very hard time idling and it seems like the timing belt is struggling to turn and is barely moving.  When at idle the exhaust  seems very weak then very strong in sync with the RPMs.  It feels like it is building up pressure then releasing it every time the RPMs increase.

To compound my problems I have a coolant leak which has gotten worse lately.  I have looked at the hoses and under the car and have not found the leak.  I have read it can leak in many spots.  It seems to leak when I am driving and not when parked.  It has progressed to adding coolant every other day.

Q2. What coolant components are prone to leaking? Where all should I check for these leaks? Do my other symptoms along with this leak point to head gasket problems?

Q3. I am not sure what to do next.  I have looked at cleaning the ETM and will probably try this next.  I am not eligible for free replacement from Volvo for this 2001 model.  If cleaning does nothing how much should I expect to pay for the replacement part/programming?

Could it be a bad Catalytic converter?  Should I try cleaning this? Does a gallon a lacquer thinner in the gas tank work for this?  Soaking it in soapy water do the trick? Anybody have any aftermarket cut and clamp recommendations? 

Any advice is greatly appreciated. Many thanks!


Submitted: 5 years ago.
Category: Volvo
Expert:  Edward replied 5 years ago.
Hello, I will try to help. Is your check engine light on or off? thanks.
Customer: replied 5 years ago.

The Check engine and service lights were on codes read: P0121, P0102


Expert:  Edward replied 5 years ago.
OK, and you replaced the MAF. Did you check the fresh air pipe for any cracks? any holes in the rubber hose off the turbo? Any vacuum leaks that let unmetered air in after the MAF will cause issues.
Expert:  Edward replied 5 years ago.
I wouldn't worry about cleaning the ETM. It's probably not that dirty, and I haven't had much luck cleaning them after they set a code. "Cleaning" the ETM at first was Volvo's way of getting it to go a little further and hopefully out of warranty before they had to replace it. 94% failure rate on those btw. so If yours is original. I'm surprised it made it this far. Is it original?
Customer: replied 5 years ago.

Thank you for the quick reply + info,

Yes the MAF was replaced. The fresh air pipe look fine. The turbo hose is going from next to radiator to ETM correct? if so, it looks intact but has some oil build up on the bottom directly below the ETM and even more at the connection near the radiator.


I would really like to test fro vacum leaks and unmetered air as a starting point. I replaced all the lines I could see and reach easily but wonder where else they live. Are there instructions on how to do a smoke test anywhere?


I bought the car with 60k on it and would guess that the ETM is original. Any recommendations on replacing it without going to the dealer?

Expert:  Edward replied 5 years ago.
Is the sticker on the front of the ETM yellow or white? Smoke test requires a machine (like a fog machine at a concert) and adaptors that pressurize the intake system at the MAF. . Friend of mine used to blow smoke from a cigarette into the vacuum lines, but he didn't have much success at that. Without that machine I don't know how to tell you to smoke test it.
Expert:  Edward replied 5 years ago.
Ever check the fuel pressure? with a gauge on the fuel rail? Should be running at 40 psi. Check the fuel pressure regulator vacuum line. If you smell or see gas in that fuel pressure regulator vacuum line, that will allow raw fuel to be sucked in the engine and give you all kinds of problems.
Customer: replied 5 years ago.

Yeah thats pretty funnny about your friend, I was hoping to throw a smoke bomb in it somewhere.


The ETM has a yellow sticker.

Never checked the fuel pressure. Will do.. Where can I find the fuel pressure regulator vucuum line? I will look at that as well.

Expert:  Edward replied 5 years ago.
OK, The yellow sticker are the original ones, Your's made it just out of the 10 year extended warranty period. I hate to be the bearer of bad news, but with that code and the way it's acting, It will most likely need one, the fuel pressure regulator is on the fuel rail, near the injectors towards the front of the engine. If fuel pressure is with in spec (around 40 psi) and that code PO121 comes back. I'm fairly certain you'll need an ETM. The bad news is that's about 1,000 dollars at the dealership. However, There is a company that is remanufacturing them now called Xemodex which is about 50% of that. It's a plug n play too because when you get one from them, the software doesn't need to be downloaded like at the dealership. (Which results in another charge). Here is the link to Xemodex.
Customer: replied 5 years ago.

Thank you so much for the information, I really appreciate the help!


I will order a rebuilt ETM and see if that solves it.


If the problem persists what would be the next step? Is it possible that the Catalytic Converter is blocked up and causing this problem? Can cleaning it be effective, if so what is the best method? ( I have heard but find it hard to believe that a gallon of Laquer thinner in the gas tank can work, or soaking it in water/dishsoap mixture can work to remove blockages).


Last thing, about the coolant leak; Where should i check to see where it is coming from?

Do I need special tools to do a pressure test? (I really can not put much money into this car anymore so I would like to do it myself if posible. Are there any parts in coolant system that have a high percentage of failure or leaking?


Many thanks,


Expert:  Edward replied 5 years ago.
If the vehicle has good power when you nail it, then the convertor is most likely NOT stopped up. I have seen a couple, but Volvo convertors seem to me better than other manufacturer's convertors as far as getting clogged goes, I don't believe that is your issue. Do not put anything but fuel and/or fuel injection cleaner in the tank, I don't recommend paint thinner in the fuel tank. Cleaning the throttle body is best done by removing the throttle body, on your vehicle, that is not the easiest task in the world, but it can be done, you remove the electric fan assembly for more access. the 7mm bolt that holds the fresh air hose to the ETM. and 4 10mm ETM bolts from the bottle of the vehicle with a long 1/4 inch extension is how I do it. Also, You will need to remove the rear starter bracket, because Volvo for some reason ran the harness behind that starter bracket. I route the wires differently when re-assembling and secure them with a tie wrap. The coolant leak could be from anywhere, the main areas are radiator (near the tanks where they are crimped). or water pump, or hoses can leak. There is a cooling system pressure tester than can screw onto the coolant overflow tank that can pressurize the cooling system when it's cold to find leaks. Pay close attention to the radiator and hoses near the intake manifold.
Edward and 2 other Volvo Specialists are ready to help you
Customer: replied 5 years ago.

Tightened up all clamps on air hoses after one hose popped off turbo.


Reset computer by disconnecting battery terminals, zip tying them together for 10 minutes, pressing brake fully 3 times, then rubbed my stomach and patted my head..


Check engine and service light are GONE. Idle is STEADY at 800 RPM. NO Stahling of engine. Test drove for 20 miles and power has increased MAJORLY. I hope this isnt just temporary good behavior. If codes return, Im swapping out the ETM.


The coolant leak is coming from behind the timing belt and not the tank or radiator. Looking at the timing belt with covers off from the passenger side it seems to be the gear between 6 & 9 o'clock. Im guessing this is the water pump? Can you give me some insight on how much the part/repair would cost? Any links or info on DIY? Are there any coolant system leak stoppers available that are effective, as I expect the water pump replacement to be pretty involvOing?


Thanks so much for your help!

Expert:  Edward replied 5 years ago.
It definitely sounds like the water pump. Water pump replacement involves removing and replacing the timing belt. OK, If any hose pops off (and they can) you probably found your biggest problem. This is important, Your 5 cyl. engine is an interference engine! Which means if that timing belt breaks, It will bend valves and then you have to remove the cylinder head and have new valves installed. You DO NOT want that to happen. Replacing the timing belt/water pump is somewhat detailed. and If you have not ever done one on a Volvo, Then I wouldn't recommend you doing it, as getting the cams timed correctly involves some special tools, (one to hold the crank, and 2. to tensioner the belt correctly). I don't know you skilll level, and I don't mean to sound like I'm criticizing, but I've seen more than one Volvo towed to the dealership with bent valves after a timing belt was attempted. So, It would be my advice, to call some prominent local import shops and ask them what they will do a timing belt/water pump for on your model Volvo. A reasonable amount for that job is 3-4 hours labor and around 200 in parts.
Expert:  Edward replied 5 years ago.
The mileage interval that Volvo says replace the belt is 105K. If it's never been done, then I would get it done ASAP.