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For 1990-2009 cars only
Table 1: DTC P0459 Evaporative Emission (EVAP) Purge Solenoid Control Circuit High Voltage

Circuit Description

The evaporative emission (EVAP) canister purge valve is used to purge fuel vapor from the EVAP canister to the intake manifold. The EVAP canister purge valve is pulse width modulated (PWM). Ignition voltage is supplied directly to the EVAP canister purge valve. The engine control module (ECM) controls the solenoid by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. If the ECM detects the control circuit voltage is more than a predetermined value when the circuit is commanded ON, this DTC sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0459 Evaporative Emission (EVAP) Purge Solenoid Control Circuit High Voltage

Conditions for Running the DTC

    • The engine speed is more than 80 RPM.
    • The ignition 1 voltage is between 10.5-18 volts.
    • The ECM has commanded the EVAP canister purge valve ON and OFF at least once during the ignition cycle.
    • DTC P0459 runs continuously once the above conditions have been met.

Conditions for Setting the DTC

    • The ECM detects the voltage on the EVAP canister purge valve control circuit is more than 4.6 volts when the driver is commanded ON.
    • The condition exists for more than 4 seconds.

Action Taken When the DTC Sets

    • The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

    • The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

The following table illustrates the ECM connector locations:

ECM Connector Location

C2

C1

Front of Vehicle

    • Use the J 35616-A/BT-8637 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
    • If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the circuit status for the component with a scan tool. The circuit status parameter changes from OK or Indeterminate to Fault if there is a condition with the circuit or a connection. The ODM information is in the output driver module (ODM) data list.
    • For an intermittent condition, refer to Intermittent Conditions .

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step determines if a condition exists. The EVAP canister purge valve is PWM. An audible click should be heard when the purge valve is commanded to 50 percent and should stop when the EVAP canister purge valve is commanded to 0 percent. The rate at which the valve cycles should increase as the commanded state is increased and decreased as the commanded state is decreased. Repeat the commands as necessary.

DTC P0459 Evaporative Emission (EVAP) Purge Solenoid Control Circuit High Voltage

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Start the engine.
  2. Allow the engine to reach operating temperature.
  3. Observe the DTC Info with a scan tool.

Does the DTC fail this ignition?

Go to Step 4

Go to Step 3

3

  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 4

Go to Diagnostic Aids

4

  1. Turn OFF the ignition.
  2. Disconnect the evaporative emission (EVAP) canister purge valve harness connector.
  3. Turn ON the ignition, with the engine OFF
  4. Connect a test lamp between the control circuit of the EVAP canister purge valve to the engine control module (ECM) housing.

Does the test lamp illuminate?

Go to Step 5

Go to Step 6

5

Important: The control circuit for the solenoid is pulled-up to voltage within the ECM, 2.6-4.6 volts on the control circuit is normal.

Test the control circuit of the EVAP canister purge valve for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 10

Go to Step 7

6

Test for shorted terminals and for poor connections at the EVAP canister purge valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 10

Go to Step 8

7

Test for shorted terminals and for poor connections at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 10

Go to Step 9

8

Replace the EVAP canister purge valve. Refer to Evaporative Emission Canister Vent Solenoid Valve Replacement .

Did you complete the replacement?

Go to Step 10

--

9

Replace the ECM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 10

--

10

  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 11

11

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK