Surging idle!! Help!!
 

ok so I just bought my 01 s60 t5. I bought it with it needing the TB replaced so I had that replaced and I also replaced the MAF sensor. It ran fine for a month and i didnt even drive it 200 miles. Yesterday I started it and it was surging like crazy at idle but when driving it run fine until you slow down. I just replaced the speedo and i also changed the coolant. Could a speedo or coolant change cause this?! I need some help please!

You said you had the TB (I assume you meant the ETM assembly?) replaced.

Did you install a new OEM type from Volvo, or an after-market unit?

I am going through the same problem* now, so am interested in following this thread.

Are you getting any text message, or MIL (CEL)?

Bob
'01 S60 T5 104,000mi
*More-or-less. Mine surges on light throttle, but is OK at idle or with heavy accerelation.

yes i did mean the ETM assembly and i had volvo replace it at the dealership so im guessing it is OEM, when i replaced the the MAF sensor it was an aftermarket. Im not getting an messages from my reader.

Since you had your Volvo dealer replace it, I am sure you went back to them with the car.

What did THEY say?

I am sure their work is warrantied so that's the first place I would start, THEN come back here and update us if you would. Did they replace it under the ETM Campaign of free replacement under the 200,000mi or 10 year terms?

The ETM problem is well known, unfortunately, but you may have something else at work here. Most things would throw a code (fuel trim, for example) that affect the idle.

As far as the coolant or speedo, I doubt either could cause the problem, though the speedo gets signals from the speed sensor through (I imagine) the ECU, so if the ecu wiring was somehow damaged, then "perhaps" would be my guess, but otherwise, even a bad speedo shouldn't cause a problem I wouldn't think.

"Modern" cars are far more complicated and the newest ones need the computer re-flashed with "adaptations" when things like power steering pumps, or alternators, or other parts are changed, but I do not think the speedo would in an '01 S60.

Again, you should have a 90 day warranty on the ETM, so ask Volvo.