Ignition "OFF" & Engine "OFF".
Ignition "ON" & Engine "OFF".
Connect scantool and select "Diagnostic Trouble Codes(DTCs)" mode.
Using a scantool, Clear DTC.
Select "Diagnostic Trouble Codes(DTCs)" mode again.
Are any DTCs present ?
![]() | ▶ Substitute with a known-good HECU and check for proper operation. If problem is corrected, replace HECU and then go to "Verification of Vehicle Repair" procedure. |
![]() | ▶ Fault is intermittent caused by faulty HECU or was repaired and HECU memory was not cleared. Go to "Verification of Vehicle Repair" procedure. |