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DTC P1237/17645 - Cylinder 1 Injector Open Circuit

NOTE: DTC is set when cylinder No. 1 fuel injector or wiring to fuel injector has an open circuit.
  1. Turn ignition off. Disconnect Electronic Control Module (ECM) connector. Connect Test Box (VAG 1598/18) to ECM wiring harness. Terminal assignments of test box are identical to ECM connector's.
  2. Remove fuse No. 18. Using a DVOM, check resistance between fuse No. 18 connector lower terminal and test box socket No. 24. Resistance should be 15-23 ohms. If resistance is not as specified, go to next step. If resistance is as specified, go to step 4).
  3. Disconnect cylinder No. 1 fuel injector connector. Check resistance between cylinder No. 1 fuel injector connector terminal No. 1 and fuse No. 18 connector lower terminal. Resistance should be less than 1.5 ohms. If resistance is as specified, go to next step. If resistance is not as specified, locate and repair open circuit between cylinder No. 1 fuel injector 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 step 5).
  4. Check resistance between cylinder No. 1 fuel injector connector terminal No. 2 and test box socket No. 24. Resistance should be less than 1.5 ohms. If resistance is as specified, go to next step. If resistance is not as specified, locate and repair open circuit in activation wire between cylinder No. 1 fuel injector 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 step. 6).
  5. Check resistance between cylinder No. 1 fuel injector terminals No. 1 and No. 2. Resistance should be 15-23 ohms. If resistance is as specified, go to next step. If resistance is not as specified, replace faulty cylinder No. 6 fuel injector. 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. 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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