DTC Troubleshooting
DTC Troubleshooting: P0443 (92)
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 Initial Inspection and Diagnostic Overview.
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 P or N) 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 -
Go to step 5.
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 PCM.
5. Turn the ignition switch to LOCK (0), and allow the engine to cool below 140 °F (60 °C).
6. Remove the intake air duct (air flow tube).
7. Disconnect the vacuum hose (A) from the purge valve (B) in the engine compartment, and connect a vacuum pump/gauge, 0-30 inHg, to the EVAP canister purge valve.
8. Install the intake air duct (air flow tube).
9. Start the engine, and let it idle.
Is there vacuum?
YES -
Go to step 10.
NO -
Go to step 16.
10. Turn the ignition switch to LOCK (0).
11. Disconnect the EVAP canister purge valve 2P connector.
12. Check for continuity between EVAP canister purge valve 2P connector terminal No. 2 and body ground.
Is there continuity?
YES -
Go to step 13.
NO -
Go to step 38.
13. Jump the SCS line with the HDS.
14. Disconnect PCM connector B (44P).
15. Check for continuity between EVAP canister purge valve 2P connector terminal No. 2 and body ground.
Is there continuity?
YES -
Repair a short in the wire between the EVAP canister purge valve and the PCM (B3), then go to step 39.
NO -
Go to step 45.
16. Turn the ignition switch to LOCK (0).
17. Disconnect the EVAP canister purge valve 2P connector.
18. Turn the ignition switch to ON (II).
19. Measure the voltage between EVAP canister purge valve 2P connector terminal No. 1 and body ground.
Is there battery voltage?
YES -
Go to step 33.
NO -
Go to step 20.
20. Turn the ignition switch to LOCK (0).
21. Check the No. 11 LAF (15 A) fuse in the under-hood fuse/relay box.
Is the fuse OK?
YES -
Go to step 22.
NO -
Go to step 29.
22. Remove the PGM-FI subrelay (A) from the under-hood fuse/relay box.
23. Test the PGM-FI subrelay Testing and Inspection.
Is the PGM-FI subrelay OK?
YES -
Go to step 24.
NO -
Replace the PGM-FI subrelay, then go to step 39.
24. Connect EVAP canister purge valve 2P connector terminal No. 1 to body ground with a jumper wire.
25. Check for continuity between PGM-FI subrelay 4P connector terminal No. 2 and body ground.
Is there continuity?
YES -
Go to step 26.
NO -
Repair an open in the wire between the EVAP canister purge valve and the PGM-FI subrelay, then go to step 39.
26. Jump the SCS line with the HDS.
27. Disconnect PCM connector A (44P).
28. Check for continuity between PCM connector terminal A21 and PGM-FI subrelay 4P connector terminal No. 3.
Is there continuity?
YES -
Go to step 45.
NO -
Repair an open in the wire between the PCM (A21) and the PGM-FI subrelay, then go to step 39.
29. Remove the No. 15 OIL LVL (7.5 A) fuse and the PGM-FI subrelay (A) from the under-hood fuse/relay box.
30. Disconnect the A/F sensor (Sensor 1) 4P connector.
31. Disconnect the EVAP canister vent shut valve 2P connector.
32. Check for continuity between EVAP canister purge valve 2P connector terminal No. 1 and body ground.
Is there continuity?
YES -
Repair a short in the wire between the PGM-FI subrelay, the EVAP canister purge valve, the EVAP canister vent shut valve, and the A/F sensor (Sensor 1). Also replace the No. 11 LAF (15 A) fuse, then go to step 39.
NO -
Replace the under-hood fuse/relay box Under-Hood Fuse/Relay Box Removal and Installation, then go to step 39.
33. Turn the ignition switch to LOCK (0).
34. Jump the SCS line with the HDS.
35. Disconnect PCM connector B (44P).
36. Check for continuity between PCM connector terminal B3 and EVAP canister purge valve 2P connector terminal No. 2.
Is there continuity?
YES -
Go to step 37.
NO -
Repair an open in the wire between the EVAP canister purge valve and the PCM (B3), then go to step 39.
37. At the valve side, measure the resistance between EVAP canister purge valve 2P connector terminals No. 1 and No. 2.
Is there about 20 Ohms at room temperature (about 68°F, 20°C)?
YES -
Go to step 45.
NO -
Go to step 38.
38. Replace the EVAP canister purge valve EVAP Canister Purge Valve Replacement.
39. Reconnect all connectors.
40. Turn the ignition switch to ON (II).
41. Reset the PCM with the HDS.
42. Do the PCM idle learn procedure PCM Idle Learn Procedure.
43. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0443 indicated?
YES -
Check for poor connections or loose terminals at the EVAP canister purge valve and the PCM, then go to step 1.
NO -
Go to step 44.
44. Monitor the OBD STATUS for DTC P0443 in the DTCs MENU with the HDS.
Does the HDS indicate PASSED?
YES -
Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 43, go to the indicated DTC's troubleshooting.
NO -
If the HDS indicates FAILED, check for poor connections or loose terminals at the EVAP canister purge valve and the PCM, then go to step 1. If the HDS indicates EXECUTING or OUT OF CONDITION, keep idling until a result comes on.
45. Reconnect all connectors.
46. Update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM.
47. Start the engine, and let it idle.
48. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0443 indicated?
YES -
Check for poor connections or loose terminals at the EVAP canister purge valve and the PCM. If the PCM was updated, substitute a known-good PCM, then go to step 47. If the PCM was substituted, go to step 1.
NO -
Go to step 49.
49. Monitor the OBD STATUS for DTC P0443 in the DTCs MENU with the HDS.
Does the HDS indicate PASSED?
YES -
If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM Service and Repair. If any other Pending or Confirmed DTCs were indicated in step 48, go to the indicated DTC's troubleshooting.
NO -
If the HDS indicates FAILED, check for poor connections or loose terminals at the EVAP canister purge valve and the PCM. If the PCM was updated, substitute a known-good PCM, then go to step 47. If the PCM was substituted, go to step 1. If the HDS indicates EXECUTING or OUT OF CONDITION, keep idling until a result comes on.