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Home >> Alfa Romeo >> 2019 >> Giulia Base, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 10 (2.9L Pcm 1 - DTCS P0351-00 To P06DB-00) >> DTC Troubleshooting >> P0686-00-ECM Main Control Circuit Low >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different variant/trim than selected.
  1. CHECK FOR AN ACTIVE DTC 
    1. Turn the ignition on.
    2. With the scan tool, erase DTCs in the PCM-1.
    3. Perform several ignition key cycles, pausing for at least ten seconds between each cycle.
    4. Turn the ignition on.
    5. With the scan tool, read DTCs and record on the repair order.

      Did this DTC return?

      Yes 

      • Go To  2

      No 

  2. CHECK THE BATTERY SUPPLY TO THE ASD RELAY CONTROL CIRCUIT 
    1. Turn the ignition off.
    2. Remove the ASD Relay from the PDC.
    3. Turn the ignition on, engine not running.
    4. Using a 12-volt test light connected to ground voltage, probe the Battery supply for the (K51) ASD Relay Control circuit in the ASD Relay connector.

      Does the test light illuminate brightly?

      Yes 

      • Go To  3

      No 

      • Repair the Battery supply for an open or high resistance. If the fuse is found to be open, repair the ASD Relay Output circuit for a short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  3. CHECK THE ASD RELAY FOR PROPER OPERATION 
    1. Turn the ignition off.
    2. Install a known good relay in place of the ASD Relay.
    3. Turn the ignition on.
    4. With the scan tool, erase DTCs in the PCM-1.
    5. Perform several ignition key cycles, pausing for at least ten seconds between each cycle.
    6. Turn the ignition on.
    7. With the scan tool, read DTCs.

      Did this DTC return?

      Yes 

      • Go To  4

      No 

  4. CHECK THE (K51) ASD RELAY CONTROL CIRCUIT FOR A SHORT TO ANOTHER VOLTAGE SUPPLY CIRCUIT 
    1. Turn the ignition off.
    2. Remove the ASD Relay from the Power Distribution Center (PDC).
    3. Disconnect the PCM-1 C1 harness connector.
    4. Check for continuity between the (K51) ASD Relay Control circuit and all other 5 volt and 12 volt supply circuits at the PCM-1 C1 harness connector.

      Is there continuity between the (K51) ASD Relay Control circuit and any other 5 volt and 12 volt supply circuits?

      Yes 

      • Repair the (K51) ASD Relay Control circuit for a short to the circuit that showed continuity.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  5
  5. CHECK THE (K51) ASD RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND 
    1. Check for continuity between ground and the (K51) ASD Relay Control circuit at the PCM-1 C1 harness connector.

      Is there continuity between ground and the (K51) ASD Relay Control circuit?

      Yes 

      • Repair the (K51) ASD Relay Control circuit for a short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  6
  6. CHECK THE (K51) ASD RELAY CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the (K51) ASD Relay Control circuit between the ASD Relay connector and the PCM-1 C1 harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  7

      No 

      • Repair the ASD Relay Control circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  7. CHECK RELATED HARNESS CONNECTIONS 
    1. Disconnect all PCM-1 harness connectors.
    2. Disconnect all related in-line harness connections (if equipped).
    3. Disconnect the related component harness connectors.
    4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
      • Proper connector installation.
      • Damaged connector locks.
      • Corrosion.
      • Other signs of water intrusion.
      • Weather seal damage (if equipped).
      • Bent terminals.
      • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
      • Terminals that have been pushed back into the connector cavity.
      • Check for spread terminals and verify proper terminal tension.

      Repair any conditions that are found.

    5. Connect all PCM-1 harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    7. Connect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    8. With the scan tool, erase DTCs.
    9. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
    10. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      No 

      • The wiring or poor connection problem has been repaired.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
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