2003 GMC SIERRA 1500 (5.3L) FUEL TANK PRESSURE SENSOR REPLACEMENT SHORT CUT
How to replace a commonly failed fuel tank pressure sensor on GMC sierra.
- 15 mm socket
- pick set (optional)
- Fuel tank pressure sensor
The most common way to replace a commonly failed fuel tank pressure sensor is to remove the fuel tank since the sensor is on top of the fuel sending unit; however, you do not have to on sierra trucks. It is not easy is you are not good at working where you can't see. It is possible to go between the bed and the top of the tank from the outside of the frame rail and get to this sensor.
For this customer, he was showing a P0446 code. Most people will replace the EVAP canister and it won't fix the problem. Using a scanner that will read live data shows that the tank pressure sensor has very low voltage and a mmHg (pressure) reading that is too high. Removing the fuel cap did not change this reading. This leads me to believe that the sensor has failed. After replacing the sensor, the readings for voltage and mmHg were correct and within range. Attached is the readings from the scanner.
Removal: Start by disconnecting the negative battery terminal. Use compressed air to blow off the top of the sending unit so little to no dirt can get into the fuel tank. Going from the outside of the frame rail, reach above the fuel tank and feel for the fuel tank pressure sensor. A flash light and mirror will help you to find this. This will be on the right side. Once this has been found, remove the electrical connector on the sensor. You can now remove the sensor. Use a pick to help you get under the sensor and remove it. The only thing holding it in is the rubber grommet on the sensor. Be careful not to break off the nipple in the tank. This will be difficult to get out and could fall into the tank.
Installation: Once the sensor is removed, you can install the new sensor. A little soapy water on the rubber will help you press it into the hole on the sending unit. Once the sensor is in, reconnect the electrical connector. This will complete the install.
TIP: If it is hard to get your hand between the tank and the bed, you can loosen the tank straps to lower the tank some. Do not remove the bolt all the way or the tank will fall out and cause damage.