Fuel Pressure Sensor Replacement (C30, S40, V50, C70)
If you car begins to exhibit strange throttle behavior, lacks throttle response, or has surging power, the likely culprit is the fuel pressure sensor. It's very common for this sensor to get gunked up around 100k miles while some of the early sensors from 2004-2007 may fail prematurely due to a flaw in the Bosch sensors used. If left unfixed for an extended period of time, the sensor may completely fail and throw a check engine light, stall out the car, or even prevent it from starting.
Even if your car is not exhibiting any of the typical symptoms, I still highly recommend replacing the sensor as preventative maintenance. A failing sensor can drastically affect gas mileage.
Luckily, new sensors are fairly cheap and easy to replace. Here's how:
- Fuse puller tool (you may use the tool located in the engine bay fuse box)
- T25 torx driver
- T25 torx bit with a crescent wrench which can turn it (often an 8mm or 1/4in wrench)
- Flat head screw driver
- 8mm or 10mm socket wrench
Fuel Pressure Sensor Replacement:
Locate the fuse box under the glove box and remove the 15amp fuse located in position #74. Please refer to your owners manual for fuse box access and exact fuse location. Pulling this fuse will disable your fuel pump relay.
Start the car and let it stall out from idling. With the fuel pump disabled, pressure will not be built up in the rail and the car will stumble from fuel starvation. After the car stalls out, attempt to start it again. Repeat this step as many times as necessary until the car fails to start, generally on the 3rd of 4th try.
Using the 8mm or 10mm socket, disconnect the negative terminal to the battery. You will be working with gasoline and fumes, which may ignite if exposed to a spark.
Locate the pressure valve on the end of the fuel rail. Remove the blue cap, place some towels around the valve, then push the center pin with a flat head screw driver to release any remaining pressure in the fuel rail. Be prepared for a bit of gas to spray out if there is any pressure left in the rail.
Remove the T25 torx screws which hold the timing belt cover in place, then remove the timing belt cover.
Locate the fuel pressure sensor on the opposite end of the fuel rail. Using the T25 torx bit and wrench, remove the single screw which holds the sensor in place. Be extremely careful not to drop the torx bit or screw.
Place a few towels below the sensor, especially over the alternator, then disconnect the electrical clip and pull the sensor off of the rail. If it appears to be stuck, you may gently prey it off using a flat head screw driver. A small amount of fuel may leak out of the rail once the sensor is removed.
Follow these instructions in reverse order to replace the new sensor. I advise allowing the engine bay to ventilate for one hour before reconnecting the battery. If a spark occurs with lingering gas fumes, it may be a risk for a fire. Do not forget to replace the #74 fuse before attempting to start the vehicle.
Upon initial start, the vehicle may momentarily stumble as it builds up pressure in the fuel rail. Allow the car to idle for a few minutes before taking it for a test drive; idle and acceleration should now remain smooth with no surges in power.
And that's all there is to it! This service requires minimal tools and time, so think about tackling it yourself before taking the car into a shop.
Written By: Michael Hallock
Michael lives in Dahlonega, GA where he works full time as manager of an accounts receivable department. Despite a bachelors in New Media Arts, his true passion is in modifying and maintaining the cars that he and his wife own; Volvo for life. Many in the Volvo community might recognize his screen name, MyNameIdeasWereTaken.