System Description
The evaporative emission (EVAP) system includes the following components:
| • | Fuel tank |
| • | EVAP vent solenoid |
| • | Fuel tank pressure sensor |
| • | Fuel pipes and hoses |
| • | Fuel vapor lines |
| • | Fuel cap |
| • | EVAP canister |
| • | Purge lines |
| • | EVAP emission canister purge valve |
| • | EVAP service port |
The EVAP purge canister solenoid is controlled by the engine control module (ECM). The ECM applies a ground to the EVAP purge canister solenoid. The ECM determines when to activate the EVAP canister purge solenoid depending on operating conditions, including throttle position (TP), engine speed, engine coolant temperature (ECT), and ambient temperature.
The DTC will detect an open or short circuit.
Conditions for Setting the DTC
| • | The ignition is ON. |
| • | Ignition voltage is greater than 11 volts. |
Action Taken When the DTC Sets
| • | The malfunction indicator lamp (MIL) will illuminate after 3 consecutive trips with a fail. |
| • | The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers. |
| • | A history DTC is stored. |
Conditions for Clearing the MIL/DTC
| • | The MIL will turn OFF after 4 consecutive ignition cycles in which the diagnostic runs without a fault. |
| • | A history DTC will clear after 40 consecutive warm-up cycles without a fault. |
| • | DTCs can be cleared by using a scan tool. |
| • | Disconnect the ECM battery feed for more than 10 seconds. |
Diagnostic Aids
Using Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If the DTC cannot be duplicated, the information included in the Freeze Frame and/or Failure Records data can be useful in determining how many miles since the DTC set. The fail counter and the pass counter can also be used to determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same Freeze Frame conditions, such as RPM, load, vehicle speed, temperature, etc., that were noted. This will isolate when the DTC failed.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Perform an On-Board Diagnostic (EOBD) System Check. Was the check performed? | -- | Go to Step 2 | |
2 |
Does the solenoid turn ON and OFF with each command? | ON - 99% OFF - 0% | Go to Step 3 | Go to Step 5 |
3 |
Does the current draw measure less than the specified value? | 0.75 A | Go to Diagnostic Aids | Go to Step 4 |
4 |
Does the ohmmeter display infinite resistance? | -- | Go to Step 12 | Go to Step 10 |
5 |
Does the test light turn ON and OFF with each command? | -- | Go to Step 8 | Go to Step 6 |
6 | With a test light connected to ground, probe the ignition feed circuit, terminal 2 in the solenoid harness connector. Does the test light illuminate? | -- | Go to Step 7 | Go to Step 11 |
7 |
Does the solenoid operate? | -- | Go to Step 9 | Go to Step 10 |
8 | Inspect the connections at the solenoid. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 12 |
9 | Inspect the connections at the powertrain control module (PCM)/ECM. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 13 |
10 | Repair the faulty solenoid control circuit. Did you complete the repair? | -- | Go to Step 14 | -- |
11 | Repair the faulty solenoid ignition feed circuit. Did you complete the repair? | -- | Go to Step 14 | -- |
12 |
Did you complete the replacement? | -- | Go to Step 14 | -- |
13 |
Did you complete the replacement? | -- | Go to Step 14 | -- |
14 |
Does the scan tool indicate that this diagnostic has run and passed? | -- | Go to Step 15 | Go to Step 2 |
15 | Are any DTCs displayed that have not been diagnosed? | -- | Go to applicable DTC table | System OK |
