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Home >> Chevrolet >> 2017 >> SS Automatic Trans >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls And Fuel - 6.2L (LS3) - Diagnostic Information And Procedures >> Diagnostic Information and Procedures >> DTC P0685, P0689, P0690, or P1682: Engine Controls Ignition Relay, Ignition 1 Switch Circuit 2 >> Circuit/System Testing

Circuit/System Testing

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 B+ 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 1 V between ground and connector terminal 47.
      • If 1 V or greater, repair the short to voltage in the circuit.
      • If less than 1 V, replace the K20 Engine Control Module.
    • If the test lamp does not illuminate 
  5. Ignition OFF, connect a 20 A fused jumper wire between the B+ circuit terminal 30 and the 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 2 Ω in the relay switch ignition voltage circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω
    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 1 V.
    • If 1 V or greater 
    1. Ignition OFF, disconnect the X1 connector at the K20 Engine Control Module.
    2. Ignition ON.
    3. Test for less than 1 V on the relay control circuit.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V
    4. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • if less than 2 Ω, replace the K20 Engine Control Module.
    • If less than 1 V 
  12. Test or replace the KR75 Engine Controls Ignition Relay.
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