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Chris (aka- Moose)
Chris (aka- Moose), Technician
Category: Transmissions
Satisfied Customers: 46447
Experience:  16 yrs. experience with auto, manual, & CVT drivelines
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My 2006 Volvo XC90 V8 kicks down gears quite quickly when I

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My 2006 Volvo XC90 V8 kicks down gears quite quickly when I hit try to accelerate at highway speed. By way of comparison, our 2004 XC90 with the T5 tends to hold gear and just accelerate in the same gear under the same gas pedal pressure. Is that normal for the V8's? It almost seems like it has less power than the T5. There are no codes coming up on the ECM or the transmission (I have an Aurelia Maxidiag reader).

Welcome, I'm Chris (aka Moose), my normal schedule online is around lunch and after dinner past midnight.

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Customer: replied 5 months ago.
Actually I was wrong that there's no codes showing on the Volvo ECM. It looks like one of the intake manifold runner controls is stuck closed, so this could be robbing the engine of power. Is there anybody there who can help me check that first?
Customer: replied 5 months ago.
34;Autel" auto-corrected to Aurelia for some reason. Anyhow, the Volvo trans,is Simon module isn't reporting anything. The vehicle has been used for some light towing, has 220,000km on it, and apparently had a tranny flush 4-5 years ago. These are sealed transmissions, so I can't even really check the fluid.
Customer: replied 5 months ago.
Transmission, not "trans,is Simon"

How did you come to the conclusion that the runner control is stuck closed with no codes stored?

Customer: replied 5 months ago.
Although no OBD codes are showing and the MIL is not on, a Volvo specific scanner found faults recorded in the ECM that I had overlooked when I first posted my question. I had cleared the fault, ran the car down the highway for a few hours and it came back again. Are there any Volvo guys there available that are familiar with these two engines and whether a stuck IMRC could make the trannys shift so differently under acceleration?

The IMRC is going to effect the engines power. When the runner is commanded open the computer expects X performance but if it gets Y instead this will effect the way the transmission operates because it to is being commanded by the computer based on getting X performance from the engine. At most a IMRC concern may cause the trans line pressure to be a little off or the time when it up or downshifts based on throttle pressure. It will not cause a harsh shift or wrong gear or slipping.

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Customer: replied 5 months ago.
Sorry, Chris, you didn't tell me anything I didn't already know, as you'll see by reading my messages. I repeatedly asked for help from a Volvo tech, and specifically asked for assistance diagnosing the IMRC fault.

I will opt out so someone else can help.

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Customer: replied 5 months ago.
Thank you, ***** ***** that!