Circuit Description
The powertrain control module (PCM) uses the fuel level input in order to calculate the expected vapor pressures within the fuel system. These vapor pressures vary as the fuel level changes. The vapor pressure is critical in determining if the Evaporative Emissions system is operating properly. The PCM also uses the fuel level in order to determine if the fuel level is too high or too low to be able to accurately detect EVAP system malfunction.
Conditions for Setting the DTC
The fuel level sensor is more than 98% for 25 seconds or more.
Action Taken When the DTC Sets
| • | The PCM records the operating conditions at the time the diagnostic fails. The Failure Records buffers will store this information. |
| • | A History DTC is stored. |
| • | The fuel tank level defaults to 40 percent. |
Conditions for Clearing the DTC
| • | A History DTC clears after 40 consecutive warm up cycles without a fault. |
| • | Use a scan tool to clear the DTCs. |
Diagnostic Aids
| • | An intermittent problem may be caused by the following conditions: |
| - | Poor electrical connection |
| - | Rubbed through wire insulation |
| - | A wire that is broken inside the wire insulation |
| • | Any circuitry, that is suspected as causing the intermittent complaint, should be thoroughly checked for the following conditions: |
| - | Backed out terminals |
| - | Improper mating |
| - | Broken locks |
| - | Improperly formed or damaged terminals |
| - | Poor terminal to wire connection |
Test Description
The numbers below refer to the step numbers on the Diagnostic Table.
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This step determines if the malfunction is present.
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Using the Freeze Frame and/or Failure Records data may aid in locating an intermittant condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass and/or fail. Operate the vehicle within the same freeze frame conditions (RPM,load,vehicle speed, temperature, etc.) that you observed. This will isolate when the DTC failed.
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Use the connector test adapter kit to avoid damage to the harness connector terminals.
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The replacement PCM must be programmed and the Crankshaft Position System Variation Learn Procedure must be performed. Refer to the latest Techline information for PCM programming.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to | |
Is the Fuel level sensor above the specified value? | 98% | |||
Does the scan tool indicate that this diagnostic failed this ignition? | -- | Go to Diagnostic Aids | ||
Is the voltage near the specified value? | 5.0 V | |||
5 | Check for an open in the Fuel level signal circuit. Was a problem found? | -- | ||
6 | With a test light connected to B+, probe the Fuel Level Sensor ground circuit. Is the test lamp ON? | -- | ||
7 | Check the harness connector at the Fuel Level Sensor for corrosion and improper mating. Was a problem found? | -- | ||
8 | Check the Fuel Level Sensor signal circuit for a short to voltage. Was a problem found? | -- | ||
9 |
Does the DMM display continuity within the specified range from the Fuel level sensor signal circuit to any other PCM circuit? | 0-2ohms | ||
Did you find and repair the condition? | -- | |||
11 | Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
12 | Repair the Fuel level sensor ground circuit, including the PCM connections. Refer to Wiring Repairs or Connector Repairs in Wiring Systems. Did you find and repair the concern? | -- | ||
13 | Repair the short between the Fuel level sensor signal circuit and the PCM circuit that had continuity. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
14 | Repair the connector as necessary. Refer to Connector Repairs in Wiring Systems. Is the action complete? | -- | -- | |
15 | Replace the Fuel level sensor. Refer to Fuel Level Sensor Replacement Is the action complete? | -- | -- | |
16 |
Important:: Program the replacement PCM. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Is the action complete? | -- | -- | |
17 |
Does the scan tool indicate that this test ran and passed? | -- | ||
18 | Select the Capture Info option and the Review Info option using the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to applicable DTC table | System OK |
