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DTC P1426/17834 - Tank Ventilation Valve Circuit Open

NOTE: ECM sets DTC if it senses an Evaporative (EVAP) canister purge regulator valve or circuit open.
  1. Turn ignition off. Disconnect EVAP canister purge regulator valve connector. Disconnect ECM connector. Connect Test Box (VAG 1598/18) to ECM wiring harness. Terminal assignments of test box are identical to ECM connector's.
  2. Jumper test box sockets No. 1 and 6. Turn ignition on. Using DVOM, check voltage between regulator valve connector terminal No. 2 and ground. Voltage should be at least 11.5 volts. If voltage is as specified, go to step 6). If voltage is not as specified, go to next step.
  3. Turn ignition off. Check resistance between regulator valve connector terminal No. 1 and test box socket No. 31. Resistance should be less than 1.5 ohms. If resistance is as specified, go to step 6). If resistance is not as specified, go to next step.
  4. Remove fuse No. 18. Check resistance between regulator valve connector terminal No. 2 and fuse No. 18 connector upper terminal. Resistance should be less than 1.5 ohms. If resistance is as specified, go to step 6). If resistance is not as specified, locate and repair open circuit between regulator valve connector and ECM. Go to next step.
  5. Check resistance between regulator valve connector terminal No. 1 and test box socket No. 1. Resistance should be infinite (no continuity). If resistance is as specified, go to next step. If resistance is not as specified, locate and repair short circuit to ground between regulator valve connector and ECM. Erase DTC memory and test drive vehicle. See CLEARING DTCS in this article. Recheck DTC memory and verify DTC does not reset. If DTC resets, go to next step.
  6. Check resistance between regulator valve terminals No. 1 and 2. Resistance should be 20-50 ohms. If resistance is as specified, go to next step. If resistance is not as specified, replace regulator. Erase DTC memory and test drive vehicle. See CLEARING DTCS in this article. Recheck DTC memory and verify DTC does not reset. If DTC resets, go to next step.
  7. Replace faulty ECM. Test drive vehicle. Recheck DTC memory and verify DTC does not reset. If DTC resets, repeat testing procedure.
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