3.
Is the measured siganl waveform normal?
 | ▶ Substitute with a known - good ECM and check for proper operation. If the problem is corrected, replace ECM and go to "Verification of Vehicle Repair" procedure. note There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by ECM. Before or after testing ECM on the vehicle, use this function to reuse the ECM on the others |
 | ▶ Substitute with a known - good PCSV and check for proper operation. If the problem is corrected, replace PCSV and go to "Verification of Vehicle Repair" procedure. |
