DTC Troubleshooting

Control System DTCs

DTC Troubleshooting: P0443

DTC P0443 : EVAP Canister Purge Valve Circuit Malfunction

Special Tools Required

Vacuum Pump/Gauge, 0-30 inHg Snap-on YA4000A or equivalent, commercially available
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information How To Troubleshoot The Fuel And Emissions Systems.

1. Problem verification:

Problem verification
-1. Turn the ignition switch to ON (II).

-2. Clear the DTC with the HDS.

-3. Start the engine. Hold the engine speed at 3,000 rpm without load (in neutral) until the radiator fan comes on, then let it idle.

-4. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0443 indicated?
-YES- The failure is duplicated. Go to step 2.
-NO- Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the EVAP canister purge valve and the ECM.

2. Determine possible failure area (EVAP canister purge valve stuck open failure, EVAP canister purge valve stuck closed failure):

Determine possible failure area (EVAP canister purge valve stuck open failure, EVAP canister purge valve stuck closed failure)
-1. Turn the ignition switch to LOCK (0), and allow the engine to cool below 140 °F (60 °C).

-2. Disconnect the vacuum hose (A) from the EVAP canister purge valve (B) in the engine compartment, then connect a vacuum pump/gauge, 0-30 inHg, to the hose.





-3. Start the engine, and let it idle.

Is there vacuum?
-YES- The EVAP canister purge valve is stuck open. Go to step 3.
-NO- The EVAP canister purge valve is stuck closed. Go to step 5.

3. Determine possible failure area (PC_SOL line, EVAP canister purge valve):

Determine possible failure area (PC_SOL line, EVAP canister purge valve)
-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the following connector.





-3. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- There is a problem in the PC_SOL line. Go to step 4.
-NO- Replace the EVAP canister purge valve Service and Repair, then do the repair verification.

4. Shorted wire check (PC_SOL line):

Shorted wire check (PC_SOL line)
-1. Jump the SCS line with the HDS.

-2. Disconnect the following connector.





-3. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- Repair a short in the PC_SOL wire between the ECM (B3) and the EVAP canister purge valve, then do the repair verification.
-NO- The PC_SOL wire is OK. Update the ECM ECM/PCM Update if it does not have the latest software, or substitute a known-good ECM Service and Repair, then do the repair verification.

5. Open wire check (IG1 line):

Open wire check (IG1 line)
-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the following connector.





-3. Turn the ignition switch to ON (II).

-4. Measure the voltage between test points 1 and 2.









Is there battery voltage?
-YES- The IG1 wire is OK. Go to step 6.
-NO- Repair an open in the IG1 wire between the EVAP canister purge valve and the No. B2 (15 A) fuse in the under-dash fuse/relay box, then do the repair verification.

6. Open wire check (PC_SOL line):

Open wire check (PC_SOL line)
-1. Turn the ignition switch to LOCK (0).

-2. Jump the SCS line with the HDS.

-3. Disconnect the following connector.





-4. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- The PC_SOL wire is OK. Go to step 7.
-NO- Repair an open in the PC_SOL wire between the ECM (B3) and the EVAP canister purge valve, then do the repair verification.

7. EVAP canister purge valve internal resistance check:

EVAP canister purge valve internal resistance check
-1. At the purge valve side, measure the resistance between test points 1 and 2.









Is there about 23-26 Ohms at room temperature?
-YES- The EVAP canister purge valve is OK. Update the ECM ECM/PCM Update if it does not have the latest software, or substitute a known-good ECM Service and Repair, then do the repair verification.
-NO- Replace the EVAP canister purge valve Service and Repair, then do the repair verification.

Repair verification (OBD STATUS check):

-1. Turn the ignition switch to LOCK (0).

-2. Reconnect all connectors.

-3. Turn the ignition switch to ON (II).

-4. Reset the ECM with the HDS How To Troubleshoot The Fuel And Emissions Systems.

-5. Do the ECM idle learn procedure ECM/PCM Idle Learn Procedure.

-6. Monitor the OBD STATUS for DTC P0443 with the HDS.

Does the HDS indicate PASSED, FAILED, EXECUTING, or OUT OF CONDITION?
-PASSED- Troubleshooting is complete. If the ECM was substituted, replace the original ECM Service and Repair. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.
-FAILED- Go to step 1 and recheck. If the ECM was updated, substitute a known-good ECM Service and Repair, then check the OBD STATUS again.
-EXECUTING- Keep idling until a result comes on.
-OUT OF CONDITION- Keep idling until a result comes on.