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DTC P0300/16684 - Random Misfire Detected

NOTE: DTC is set when Electronic Control Module (ECM) detects rough engine running (misfiring).
  1. Check fuel condition and tank level. Drain and/or fill if necessary. If fuel is okay, go to next step. If fuel level was low or contaminated, 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.
  2. Run engine at idle or slightly above idle. Check spark plug cables and connectors for arcing to ground. Replace spark plug cable(s) as necessary. If spark plug cables are okay, go to next step. 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.
  3. Remove and check condition of spark plugs. Check spark plugs for correct heat range. Replace spark plug(s) as necessary. If spark plugs are okay, go to next step. 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.
  4. Ensure engine speed sensor is properly installed. If speed sensor is properly installed, remove speed sensor and check for metal particle contamination. If speed sensor is okay, go to next step.
  5. Check crankshaft wheel for damage or contamination. If crankshaft wheel is okay, check condition of speed sensor connector. Repair as necessary. 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. Turn ignition off. Disconnect ignition coil connector. Turn ignition on. Using DVOM, check voltage between ignition coil connector terminals No. 1 and 3 on 2.0L or No. 1 and 5 on 2.8L. Voltage should be 11.5 volts. If voltage is as specified, go to step 10). If voltage is not as specified, go to next step.
  7. Turn ignition off. Disconnect ECM connector. Connect Test Box (VAG 1598/18) to ECM wiring harness. Terminal assignments of test box are identical to ECM connector's.
  8. Check resistance between ignition coil connector terminal No. 1 and test box socket No. 1. Resistance should be less than 1.5 ohms. If resistance is not as specified, go to next step. If resistance is as specified, locate and repair open circuit in positive wire to ignition coil. 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 16).
  9. Locate and repair open circuit in ground wire to ignition coil. 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 16).
  10. Turn ignition off. Disconnect ECM connector. Connect Test Box (VAG 1598/18) to ECM wiring harness. Terminal assignments of test box are identical to ECM connector's.
  11. Check resistance between ignition coil connector terminal No. 2 and test box socket No. 8. Resistance should be less than 1.5 ohms. If resistance is as specified on 2.0L, go to step 13). If resistance is as specified on 2.8L, go to next step. If resistance is not as specified, locate and repair open circuit between ignition coil 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.
  12. Check resistance between ignition coil connector terminal No. 3 and test box socket No. 60, and ignition coil connector terminal No. 4 and test box socket No. 52. 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 ignition coil 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.
  13. On all models, check resistance of ignition coil connector terminals to each other. On 2.0L, check between connector terminals No. 1 and 2, and No. 2 and 3. On 2.8L, check between connector terminals No. 2 and 3, and No. 3 and 4. On all models, resistance should be infinite (no continuity). If resistance is as specified, on 2.0L, go to next step. On 2.8L, go to step 16).
  14. Check resistance between ignition coil terminals No. 1 and 15. Resistance should be 500-1200 ohms. If resistance is as specified, go to next step. If resistance is not as specified, go to step 16).
  15. Check resistance between ignition coil terminals No. 4 and 15. Resistance should be 3000-4000 ohms. If resistance is as specified, go to next step. If resistance is not as specified, go to next step.
  16. Replace ignition coil. 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.
  17. 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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