DTC P0443 Evaporative Emission (EVAP) Purge Solenoid Control Circuit. Buick GL7 (Export) 2000

For 1990-2009 cars

Refer to Engine Controls Schematics

#### Engine Data Sensors, MAF and EGR

.

### Circuit Description

Output driver modules (ODMs) are used by the powertrain control module (PCM) to turn on many of the current-driven devices that are needed to control various engine and transaxle functions. Each ODM is capable of controlling up to 7 separate outputs by applying ground to the device which the PCM is commanding ON. A DTC P0443 set indicates an improper voltage level has been detected on the output circuit which controls the EVAP purge valve.

### Conditions for Setting the DTC

• | The ignition is ON.

• | An improper voltage level has been detected on the output circuit which controls the EVAP canister purge valve.

• | The above conditions are present for at least 30 seconds.

### Action Taken When the DTC Sets

• | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.

• | The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

### Conditions for Clearing the MIL/DTC

• | The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.

• | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

• | The DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

### Diagnostic Aids

Inspect for the following conditions:

• | A poor connection at the PCM. Inspect harness connectors for the following conditions:

- | Backed-out terminals

- | Improper mating

- | Broken locks

- | Improperly formed or damaged terminals

- | Poor terminal-to-wire connection

• | A damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the PCM, turn the ignition ON, and observe a digital multimeter (DMM) connected between the control circuit of the EVAP canister purge valve and ground at the PCM harness connector while moving the connectors and the wiring harnesses related to the EVAP canister purge valve. A change in the voltage will indicate the location of the malfunction.

Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. The Powertrain OBD System Check prompts you to complete some basic checks and store the Freeze Frame and Failure Records data on the scan tool.

2. Listen for an audible clicking when the purge valve operates. Command both the Increase and Decrease states. Repeat the commands as necessary.

3. Tests for voltage at the feed side of the solenoid.

4. Verifies that the PCM is providing ground to the EVAP purge valve.

5. Determines if ground is constantly being applied to the EVAP purge valve.

6. The PCM utilizes electrically erasable programmable read-only memory (EEPROM). If the PCM is replaced, the new PCM must be programmed.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check

2

1. Turn ON the ignition, leaving the engine OFF.
2. With a scan tool, Increase and Decrease the purge valve up and down.

Does the valve respond to each command?

--

Go to Diagnostic Aids

Go to Step 3

3

1. Turn OFF the ignition.
2. Disconnect the solenoid.
3. Turn ON the ignition, leaving the engine OFF.
4. Probe the feed circuit of the purge valve with a test lamp connected to ground.

Does the test lamp illuminate?

--

Go to Step 4

Go to Step 10

4

1. Connect a test lamp between the control circuit of the purge valve and the feed circuit of the purge valve.
2. With a scan tool, command the purge valve ON and OFF .

Does the test lamp turn ON and OFF with each command?

--

Go to Step 8

Go to Step 5

5 | Does the test lamp remain illuminated with each command? | -- | Go to Step 7 | Go to Step 6
6 | Test the control circuit of the purge valve for a short to voltage or an open. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9
7 | Test the control circuit of the purge valve for a short to ground. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9
8 | Inspect for poor connections at the purge valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11
9 | Inspect 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? | -- | Go to Step 13 | Go to Step 12
10 | Repair the feed circuit of the purge valve. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 13 | --
11 | Replace the EVAP purge valve . Did you complete the replacement? | -- | Go to Step 13 | --
12 | Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | Go to Step 13 | --

13

1. Use the scan tool in order to clear the DTCs .
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK