Circuit Description
The PCM supplies a 5 volt fuel level sensor input and a ground for the fuel level sensor. The fuel level sensor varies the voltage relative to the amount of fuel in the fuel tank. The PCM monitors the voltage on the fuel level circuit to calculate the amount of fuel in the tank. The PCM transmits the fuel level over the Class ll communication circuit to the IP cluster. This information is used by the IP cluster to operate the fuel gauge.
Diagnostic Aids
Use the following procedures to diagnosis an intermittent condition:
Many situations may lead to an intermittent condition. Perform each inspection or test as directed.
Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Loose terminal connection |
| - | Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| - | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| • | Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
| • | Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnosis (OBD) System Check? | -- | ||
2 | Perform the Fuel Gauge Inaccurate or Inoperative Diagnosis. Refer to Fuel Gage Inaccurate or Inoperative in Instrument Panel, Gauges and Console Did you find and correct the condition? | -- | ||
3 |
Does the scan tool indicate that the Fuel Level parameter is near the specified value? | 200% | ||
4 |
Does the scan tool indicate the Fuel Level parameter near the specified value? | 3.5% | ||
5 | Connect a DMM between the fuel level signal circuit and the ground circuit. Does the DMM indicate voltage near the specified value? | 5V | Go to Diagnostic Aids | |
6 | Connect the DMM between the fuel level sensor circuit and a good chassis ground. Does the DMM indicate voltage near the specified value? | 5V | ||
7 | Test the Fuel Level signal circuit for a short to ground. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
8 | Test the fuel level signal circuit for a short to voltage or an open. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
9 | Test the fuel level ground circuit for a short to voltage or an open. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
10 | Test for poor connections at the fuel level sensor harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
11 | Replace the Fuel Level Sensor. Refer to Fuel Level Sensor Replacement . Did you complete the replacement? | -- | -- | |
12 | Test the fuel level signal circuit and fuel level ground circuit for poor connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
13 |
Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you Complete the replacement? | -- | -- | |
14 | Test the fuel level system for proper operation. Does the fuel level gauge indicate proper operation? | -- | System OK |
