DTC P1172: Secondary Fuel Level Sensor - Lack Of Variation: Description

The right fuel level sensor measures fuel level changes within the right fuel tank. When the fuel level is high the sensor signal voltage is high. When the fuel level is low the sensor signal voltage is low. The control module uses inputs from the left fuel level sensor and the right fuel level sensor in order to calculate the total fuel remaining in both sides of the fuel tank. The control module sends this information via class 2 to the instrument panel cluster.

This diagnostic tests for a restriction in the fuel system between the secondary and primary of the fuel tank. If the control module determines that the fuel level, secondary side of tank, signal appears to be stuck based on a lack of signal variation expected during normal operation, this DTC sets.

The fuel pump also supplies a small amount of pressurized fuel to the siphon jet pump through the fuel feed pipe. The pressurized fuel creates a venturi action inside the siphon jet pump. The venturi action causes the fuel to be drawn out of the secondary side of the fuel tank. Fuel is then transferred from the secondary side of fuel tank to the primary side of fuel tank through the internal fuel transfer tube.

The fuel level in the fuel tank will equalize when the following occur:

• The electric fuel pump is operating.
• The fuel level is more than 50 percent.
• The vehicle is being re-fueled.