How to Repair the Fuel Cut-Off Sensor
The fuel cut-off sensor is what activates your inertia fuel shut-off switch. Either of these components might be compromised if your vehicle ever stalls on you or fails to start suddenly. They're in fact one of the first things you should check out if ever such an event were to happen. The sensor tells the switch to trip and cut power to the fuel pump in case a collision happens (so things won't go from bad to worse). However, you can also trigger it with a pothole or a large bump. You might need to reset the inertia switch by pressing down the reset button or repairing it if it still fails.
Difficulty Level: Moderate
What You'll Need
- Replacement fuse
- Socket set (metric and standard)
Step 1: Test the switch to see if it has gone bad. If it hasn't gone bad, then it might be your fuel pump that's damaged. If it is the switch, push the reset button. It can be activated by even a sharp blow of the trunk lid.
Step 2: If the vehicle isn't starting, unplug the wiring connector and test one side of the connector for the power and the other side for the ground. The ground is found through the fuel pump and the power comes from the fuel pump relay.
Step 3: If you're not getting power but there is ground then either part could be defective. Having no ground but having power indicates there's an issue with your fuel pump wiring or maybe the pump itself has a defect.
Step 4: If you have power and ground, bypass the switch with a jumper wire. If the engine starts and runs normally immediately afterwards, then the switch and/or the sensor is busted and requires immediate replacement. A reset isn't enough to fix it.
Step 5: If after putting on the jumper wire over the switch your engine still won't start, check the fuel pump's power. If there's power and ground there, then the fuel pump itself is defective rather than the switch and sensor.
Step 6: Search for your vehicle's inertial trigger or switch. Use your user's manual to do so. If it's not indicated there, look inside the driver-side or passenger-side kick panel, behind the glove compartment, and under the front seats.
Step 7: The location of the switch varies from maker, year, and model. However, there are some common places to search for. Van, SUV, and pickup trucks tend to have the sensor under the dashboard on the driver or passenger side. Cars, on the other hand, usually have it in the trunk.
Step 8: Push your switch's button. It should clearly be marked as "fuel pump reset" with a contrasting color to the case to make it even more obvious. You might need to energize the module by turning the ignition key to the accessory or on position.
Step 9: If the inertia trigger lacks a reset button, remove the cover by taking off the screws that's holding it in place or prying the plastic clips loose. Within the switch, you'll see a fuse, a circuit breaker switch, or a button.
Step 10: Flip the breaker switch or push the button back to its original position. If the switch makes use of an internal fuse, pull the fuse out and replace it with a new fuse that has the same rating. This should repair your sensor or reset it to normal.