Circuit Description
The engine control module (ECM) uses the signal from the fuel level sensor to calculate expected vapor pressure within the fuel system. Vapor pressure varies as the fuel level changes. The fuel level signal is also used to determine if the fuel level is too high or too low to be able to detect evaporative emission (EVAP) system faults. This DTC detects a continuous short to low or open in either the signal circuit or the fuel level sensor.
Conditions for Setting the DTC
| • | Fuel level sensor output is less than 2 percent of the sensor reading scale. |
| • | The ignition is ON. |
Action Taken When the DTC Sets
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in Failure Records buffers. |
| • | A history DTC is stored. |
Conditions for Clearing the MIL/DTC
| • | A history DTC will clear after 40 consecutive warm-up cycles without a fault. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnect the ECM battery feed for more than 10 seconds. |
Diagnostic Aids
| • | Inspect the harness connector for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and a poor terminal-to-wire connection. |
| • | Inspect the wiring harness for damage. |
| • | A stuck fuel level sensor may cause the DTC to set. |
| • | If the DTC P0462 cannot be duplicate, the information included on the Failure Record data can be useful in determining vehicle conditions when the DTC was first set. |
| • | Resistance measurements for fuel level sensor: |
| - | Empty equals 280 ohms or over. |
| - | Half full equals about 90 ohms. |
| - | Full equals 38 ohms or less. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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The On-Board Diagnostic System Check prompts the technician to complete some basic checks and store the Freeze Frame and Failure Records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.
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Determine if fault is present. Review Freeze Frame data to determine when the DTC set. Always record this information.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Perform an On-Board Diagnostic System Check. Was the check performed? | -- | Go to Step 2 | ||
Is DTC P0462 set? | -- | Go to Step 3 | Go to Diagnostic Aids | |
3 |
Is the voltage within the specified range? | 0.4-4.5 V | Go to Step 4 | Go to Step 6 |
4 | Inspect for a proper ground connection at the fuel tank and repair as needed. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 5 |
5 |
Does the fuel level sensor value on the scan tool increase and then decrease steadily when the float is moved? | -- | Go to Diagnostic Aids | Go to Step 8 |
6 | Inspect for an open or short to ground in the fuel level sensor circuit and repair as needed. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 9 |
7 | Repair the open or short to ground in the fuel level sensor circuit between the fuel level sensor harness connector and fuel level sensor. Did you complete the repair? | -- | Go to Step 11 | -- |
8 |
Did you complete the replacement? | -- | Go to Step 11 | -- |
9 |
Is the voltage within the specified range? | 4-5 V | Go to Step 10 | Go to Symptoms - Instrument Panel, Gages and Console in Instrument Panel, Gages, and Console |
10 |
Did you complete the replacement? | -- | Go to Step 11 | -- |
11 |
Does the scan tool indicate that this diagnostic has run and passed? | -- | Go to Step 12 | Go to Step 2 |
12 | Are any DTCs displayed that have not been diagnosed? | -- | Go to applicable DTC table | System OK |
