Although not exclusively limited to, the most likely cause of this problem might be a failing Volvo Electronic Throttle Module (ETM).
These cars use a fly-by-wire throttle. The failure is caused by wear in the internal throttle position sensor contacts.
Symptoms of failing ETM
What you might experience:
- rough and fluctuating idle
- engine stalling or dying
- hesitation on accelerations
- the engine goes into limp mode
- Illuminated check engine light
- idle fluctuates between 500 and 1000 RPM
- error codes 91A7, 9190 or 917F
If experiencing some of these symptoms, your Volvo likely has a bad electronic throttle module, especially if any codes are present.
The problem lies within the throttle position sensor that is integrated into the ETM.
Being a mechanical contact type, it relies on physical contact between two small moving parts. With time, these parts wear out, causing loss of contact. Newer cars don't experience this problem as they have contactless throttle position sensors.
Dirt on Butterfly Valve
Over time dirt and grime can build up inside the throttle body. You can remove the intake air hose connecting the throttle body. Then use Throttle Body Cleaner and a clean cloth to remove the dirt.
Remove any loose dirt from the throttle body, or it will end up in the cylinders.
As dirt build-up can cause symptoms similar to the failing ETM, checking this should be your first step. Use a cleaner to clean the throttle butterfly valve thoroughly.
Volvo ETM Failure
The Electronic Throttle Module itself can fail. Replacing your ETM with a new one is an obvious and easiest solution but also the most expensive. If done by a dealer, you are looking at a $1000+ repair. An alternative solution would be to buy a new Volvo throttle online. Keep in mind it may need to be programmed.
Replacing your ETM with a used one is a much cheaper option. Still, as with any used part, this is always risky. You don't know how long the used part will last, plus it may also need programming.
A cost-effective way to fix Volvo ETM is to have a specialist repair your existing unit. You will need to remove it and send it in for repair. As ETM failures are widespread, several specialists offer Volvo ETM repair service on eBay. See the instructions below on how to remove Volvo ETM.
If possible, ask that your specialists replace the mechanical type TPS with a contactless type, eliminating potential problems in the future.
An alternative solution is to buy a contactless Volvo throttle body position sensor on eBay repair kit and repair it yourself. As this can be done within one day, it is much faster than sending the unit to the specialist. And it will save you some money, too. However, it does require quite a bit of skill and patience and some of the more-than-basic tools.
Removal and installation procedure
Whatever the Volvo ETM repair method you choose, the ETM unit will need to be removed from the car. The good news is that there is no need to remove the manifold itself.
- Open the hood and disconnect the negative battery cable.
- Remove the intake air pipe that connects to the throttle body. Remove the inlet pipe to the air filter housing if necessary.
- Remove any pipes that go to the throttle body.
- Disconnect the ETM connector.
- Unbolt 4 bolts that hold the ETM.
- Carefully separate the ETM from the inlet manifold.
- Installation is in reverse order of removal. Always use a new ETM gasket.
If you are still experiencing problems after repairing your Volvo ETM module, read the fault codes via the Diagnostic Port located under the dashboard. To better understand the problem, use a Volvo specific scanner instead of a generic OBD2.
Whether you have acquired another ETM or have yours repaired, some programming might be required.
A sticker color can be used as a rule of thumb. Units with white stickers will require programming, also called ETM Reload, after installation.
You will need a Volvo proprietary diagnostic for this.
Otherwise, programming will need to be done by the dealer. If the tag is yellow, all you need to do is to reinstall it.