Circuit Description
The fuel level sensor changes resistance based on fuel level. The body control module (BCM) monitors the signal circuit of the fuel level sensor in order to determine fuel level. When the fuel tank is full, the sensor resistance is high and the BCM senses a high signal voltage. When the fuel tank is empty, the sensor resistance is low and the BCM senses a low signal voltage. The BCM uses the signal circuit of the fuel level sensor in order to calculate the total remaining fuel in the tank. The BCM sends the fuel level percent via the class 2 serial data circuit to the instrument panel cluster (IPC) in order to control the fuel gauge.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
| • | The fuel level signal is less than 0.4 volts. |
| • | The above condition is present for greater than 10 seconds. |
Action Taken When the DTC Sets
| • | The fuel gauge defaults to empty. |
| • | The low fuel indicator illuminates. |
Conditions for Clearing the DTC
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The history DTC clears after 40 malfunction free warm-up cycles. |
| • | The BCM receives the clear code command from the scan tool. |
Diagnostic Aids
Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Instrument Cluster Schematics | ||||
1 | Did you perform the Instrument Cluster Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Does the fuel gauge display FULL? | -- | Go to Step 4 | Go to Step 3 |
3 | Test the signal circuit of the fuel level sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 5 |
4 | Test the signal circuit of the fuel level sensor for a short to ground between C415 and the fuel level sensor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 6 |
5 | Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 7 |
6 | Inspect for poor connections at the harness connector of the fuel level sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 8 |
7 | Replace the BCM. Refer to Body Control Module Replacement in Body Control System. Did you complete the replacement? | -- | Go to Step 9 | -- |
8 | Replace the fuel level sensor. Refer to Fuel Sender Assembly Replacement in Engine Controls. Did you complete the replacement? | -- | Go to Step 9 | -- |
9 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
