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Home >> Buick >> 2015 >> Regal GS, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 17 (Engine Controls And Fuel - 2.4L - DTC P0628 To DTC P2635 And Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC P0685-P0687, P0689, P0690, or P1682: Engine Controls Ignition Relay >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
NOTE:

You must perform the Circuit/System Verification before proceeding with Circuit/System Testing unless sent here from Engine Cranks But Does Not Run.

  1. Ignition OFF, disconnect the KR75 Engine Controls Ignition Relay.
  2. Verify a test lamp illuminates between ground and the relay circuit terminals listed below:
    • terminal 85
    • terminal 30
    • If the test lamp does not illuminate 

      Replace the front compartment fuse block.

    • If the test lamp illuminates 
      NOTE:
      • High resistance in the circuit/underhood fuse block for either the KR75 Engine Controls Ignition Relay or the KR73 Ignition Main Relay can cause DTC P1682 to set.
      • A short to voltage on any of the circuits supplied by the engine controls ignition relay can cause DTC P0690 to set.
  3. Ignition ON.
  4. Verify that a test lamp does not illuminate between the ignition voltage circuit terminal 87 and ground.
    • If the test lamp illuminates 
    1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module.
    2. Ignition ON.
    3. Test for less than 1V between ground and connector terminals 73.
      • If 1V or greater, repair the short to voltage in the circuit.
      • If less than 1V, replace the K20 Engine Control Module.
    • If the test lamp does not illuminate 
  5. Ignition OFF, connect a 20A fused jumper wire between the relay switch B+ circuit terminal 30 and the relay switch ignition voltage circuit terminal 87.
  6. Ignition ON.
  7. Verify the scan tool Engine Controls Ignition Relay Feedback Signal parameter displays B+.
    • If B+ is not displayed 
    1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module
    2. Test for less than 2Ω in the relay switch ignition voltage circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω
    3. Test for infinite resistance between the relay switch ignition voltage circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K20 Engine Control Module.
    • If B+ is displayed 
  8. Ignition OFF, connect a DMM, set to the diode setting, between control circuit terminal 86 and ground.
  9. Verify the DMM displays OL.
    • If OL is not displayed 
    1. Disconnect the X1 harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between ground and the relay control circuit.
      • If less than infinite resistance, repair the short to ground in the circuit.
      • If infinite resistance, replace the K20 Engine Control Module.
    • If OL is displayed 
  10. Ignition ON.
  11. Verify the DMM displays less than 1V.
    • If 1V or greater 
    1. Ignition OFF, disconnect the X1 connector at the K20 Engine Control Module.
    2. Ignition ON.
    3. Test for less than 1V on the relay control circuit.
      • If 1V or greater, repair the short to voltage on the circuit.
      • If less than 1V
    4. Test for less than 2Ω in the control circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • if less than 2Ω, replace the K20 Engine Control Module.
    • If less than 1V 
  12. Test or replace the KR75 Engine Controls Ignition Relay.
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