Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Fuel Level Sensor Reference Voltage Circuit | P0462 | -- | -- | P0461 |
Fuel Level Sensor Signal Circuit | P0462 | P0463 | P0463 | P0461 |
Fuel Level Sensor Low Reference Circuit | -- | P0463 | P0463 | P0461 |
The primary fuel level sender and the secondary fuel level sender changes resistance based on fuel level. The powertrain control module (PCM) monitors the signal circuits of the primary fuel level sender and the secondary fuel level sender in order to determine the fuel level. When the fuel tank is full, the resistances of both fuel level senders are high and the PCM senses a high signal voltage on both the signal circuits of the primary fuel level sender and the secondary fuel level sender. When the fuel tanks are empty, the resistances of the fuel level senders are low and the PCM senses a low signal voltage. The PCM uses the signal circuits of the primary fuel level sender and the secondary fuel level sender in order to calculate the percentage of remaining fuel in the tank. The PCM sends the fuel level percentage via serial data circuit to the instrument cluster in order to control the fuel gage.
The ignition is ON, with the engine running.
• | The primary fuel level signal is greater than 4.5 volts. |
• | The above condition is present for greater than 20 seconds. |
• | The fuel gage defaults to empty. |
• | The driver information center (DIC) displays the FUEL LEVEL LOW message. |
• | The PCM records the operating conditions at the time that the diagnostic test fails. The PCM displays the failure information in the Failure Records on the scan tool. |
• | 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 PCM receives a clear code command from the scan tool. |
• | Engine Controls Schematics for the 5.7L engine |
• | Powertrain Control Module Connector End Views for the 5.7L engine |
Fuel Gage Description and Operation
With the scan tool installed and the ignition ON, the Fuel Tank Level Remaining parameter in the PCM EVAP Data List indicates a value at or greater than 98 percent.
⇒ | If greater than 1 ohm, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the PCM. |
⇒ | If greater than 98 percent, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the PCM. |
⇒ | If not within the specified range, replace the primary fuel level sensor. |
• | Primary Fuel Level Sensor Replacement for the 5.7L engine |
• | Control Module References for the PCM replacement, setup, and programming |
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Fuel Level Sensor Reference Voltage Circuit | P0462 | -- | -- | P0461 |
Fuel Level Sensor Signal Circuit | P0462 | P0463 | P0463 | P0461 |
Fuel Level Sensor Low Reference Circuit | -- | P0463 | P0463 | P0461 |
The primary fuel level sender and the secondary fuel level sender changes resistance based on fuel level. The engine control module (ECM) monitors the signal circuits of the primary fuel level sender and the secondary fuel level sender in order to determine the fuel level. When the fuel tank is full, the resistances of both fuel level senders are high and the ECM senses a high signal voltage on both the signal circuits of the primary fuel level sender and the secondary fuel level sender. When the fuel tanks are empty, the resistances of the fuel level senders are low and the ECM senses a low signal voltage. The ECM uses the signal circuits of the primary fuel level sender and the secondary fuel level sender in order to calculate the percentage of remaining fuel in the tank. The ECM sends the fuel level percentage via serial data circuit to the instrument cluster in order to control the fuel gage.
• | The engine is running. |
• | The system voltage is between 10-18 volts. |
• | Fuel level state is stable. |
• | The primary fuel level signal is about 3.2 volts. |
• | The primary fuel level sensor signal is about 64 percent. |
• | The above condition is present for about 60 seconds. |
• | The fuel gage defaults to empty. |
• | The driver information center (DIC) displays the FUEL LEVEL LOW message. |
• | The ECM records the operating conditions at the time that the diagnostic test fails. The ECM displays the failure information in the Failure Records on the scan tool. |
• | 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 ECM receives a clear code command from the scan tool. |
• | Engine Controls Schematics for the 3.6L engine |
• | Engine Controls Schematics for the 2.8L engine |
• | Engine Control Module Connector End Views for the 3.6L engine |
• | Engine Control Module Connector End Views for the 2.8L engine |
Fuel Gage Description and Operation
With the scan tool installed and the ignition ON, the Fuel Tank Level Remaining parameter in the ECM EVAP Data List indicates a value at or greater than 4.5 volts.
⇒ | If greater than 1 ohm, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | If greater than 4.5 volts, test the primary signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | If not within the specified range, replace the primary fuel level sensor. |
• | Primary Fuel Level Sensor Replacement for the 3.6L engine |
• | Primary Fuel Level Sensor Replacement for the 2.8L engine |
• | Control Module References for the ECM replacement, setup, and programming |