My car has had an intermittent problem with shutting off completely at certain situations. This occurs both while braking to a stop, like at the traffic light, as well as while accelerating from a stop. The car would shut off in these conditions and always at lower speeds. I would then have to put it in park and start it up again. There are no problems with starting the car. It starts immediately. The dealers cannot recreate the problem so they cannot solve it. No error codes came up. The repairs done so far include the alternator replacement and throttle valve control unit carbon buildup cleaning. What could be causing this?
There are numerous potential causes for your problem. One common issue with Volvos such as yours, is a faulty Electronic Throttle Module (ETM). It sounds like you had it cleaned, but it may need to be completely replaced. Using inputs from various sensors including the accelerator position sensor, the ECM uses a motor to open and close the throttle. A malfunctioning ETM can lead to engine performance problems such as stalling. I suggest you have your vehicle inspected by another mechanic to diagnose the stalling issue and see if this is indeed the problem. The team at YourMechanic is an excellent option since we make house calls.
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