Harness Inspection

Measure CKP power supply voltage. Disconnect sensor harness connector. Turn ignition on. Using DVOM, measure voltage between sensor harness connector terminal No. 2 (Red wire) and vehicle ground. If voltage is less than battery voltage, inspect and repair circuit as needed.
Check continuity of ground circuit. Turn ignition off. Using ohmmeter, check resistance between harness connector No. 1 (Black wire) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed.
Check output voltage from ECM. Turn ignition on. Using DVOM, measure voltage between harness connector terminal No. 4 (Green wire on Elantra, Yellow wire on Sonata 4-Cylinder) and vehicle ground. Voltage should be 4.8-5.2 volts. If voltage is within specification, circuit is okay. If voltage is not within specification, go to step 4).
Turn ignition off. Disconnect ECM harness connector. Connect jumper wire between ECM harness connector terminal No. 16 (Green wire, 24-pin connector) or No. 15 (22-pin connector) and vehicle ground. See Figure . Using ohmmeter, check resistance between CKP harness connector terminal No. 4 (Green wire on Elantra, Yellow wire on Sonata 4-Cylinder) and vehicle ground. If continuity does not exist, inspect and repair circuit as needed. If continuity exists, substitute ECM with known good unit and retest.