The PCM uses a fuel level input in order to calculate the expected vapor pressures within the fuel system. These vapor pressure vary as the fuel level changes. The vapor pressure is critical in determining if the evaporative emission (EVAP) 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 an EVAP system malfunction.
• | The ignition is ON. |
• | The system voltage is between 11and 16 volts. |
The fuel level sensor reading is more than 98 percent for 25 seconds or more.
• | The PCM will record the operating conditions under which the diagnostic fails. This information is stored in the Failure Records buffer. |
• | A history DTC is stored. |
• | A history DTC clears after 40 consecutive warm up cycles without a fault. |
• | Use a scan tool to clears the DTCs. |
• | Inspect for the following conditions that may cause intermittents: |
- | Poor electrical connections |
- | Rubbed through wire insulation |
- | A wire that is broken inside the wire insulation |
• | Thoroughly inspect any circuitry that is suspected as causing the intermittent complaint. Inspect for the following conditions: |
- | Backed out terminals |
- | Improper mating |
- | Broken locks |
- | Improperly formed or damaged terminals |
- | Poor terminal to wire connections |
• | Before replacing the PCM, inspect the PCM electrical connector terminals for the following conditions: |
- | Improper mating |
- | Broken locks |
- | Physical damage to the wiring harness |
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Value(s) | Yes | No | ||||
---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check ? | -- | ||||||
2 |
Is the fuel level sensor value more than the specified value? | 98% | Go to Diagnostic Aids | |||||
3 |
Did the fused jumper open? | -- | ||||||
4 | With the scan tool, observe the fuel level sensor value. Is the fuel level sensor value less than the specified value? | 3.5% | ||||||
5 | Connect a jumper wire from the sensor input circuit to ground. Is the Fuel Level sensor value more than the specified value? | 3.5% | ||||||
6 |
Did you find and correct the condition? | -- | ||||||
7 |
Did you find and correct the condition? | -- | ||||||
8 |
Did you find and correct the condition? | -- | ||||||
9 |
Did you find and correct the condition? | -- | ||||||
10 | Repair short to voltage on the Input circuit. Did you complete the repair? | -- | -- | |||||
11 | Replace the fuel level sensor. Refer to Fuel Level Sensor Replacement . Did you complete the repair? | -- | -- | |||||
Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the repair? | -- | -- | ||||||
13 |
Does the DTC reset? | -- | System OK |