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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 (A/T in P or N, M/T 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/PCM.

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

5. Open wire check (IG1(PCS) line):

Open wire check (IG1(PCS) 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(PCS) wire is OK. Go to step 6.
-NO- Repair an open in the IG1(PCS) wire between the EVAP canister purge valve and the No. B2 IG1AGS(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/PCM (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/PCM ECM/PCM Update if it does not have the latest software, or substitute a known-good ECM/PCM 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/PCM with the HDS How To Troubleshoot The Fuel And Emissions Systems.

-5. Do the ECM/PCM 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/PCM was substituted, replace the original ECM/PCM Service and Repair. If any other Pending or Confirmed DTCs were indicated, go to the indicated DTC's troubleshooting.
-FAILED- Go to step 1 and recheck. If the ECM/PCM was updated, substitute a known-good ECM/PCM 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.
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