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Home >> Chevrolet >> 2017 >> Spark LS, Standard Trans >> Repair and Diagnosis >> Electrical >> Instrument Panel System Displays And Gauges >> Diagnostic Information and Procedures >> DTC B1370: Control Module Ignition On and Start >> Circuit/System Testing
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Circuit/System Testing

NOTE: Circuit/System Verification must be performed before proceeding with Circuit/System Testing.
  1. Ignition OFF and all vehicle systems OFF, disconnect the KR74 Ignition Run Relay. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 Ω between the ground circuit terminal 86 and ground.
    • If 10 Ω or greater 
    1. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • If less than 10 Ω 
  3. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.
    • If the test lamp does not illuminate and the circuit fuse is OK 
    1. Test for less than 2 Ω in the B+ circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is OK and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    2. Test for infinite resistance between the control circuit terminal 87 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the KR74 Ignition Run Relay.
    • If the test lamp illuminates 
  4. Ignition ON.
  5. Verify that a test lamp illuminates between the ignition circuit terminal 85 and ground.
    • If the test lamp does not illuminate 
    1. Ignition OFF.
    2. Test the for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • If the test lamp illuminates 
  6. Ignition OFF, connect the KR74 Ignition Run Relay, disconnect the harness connector at the P16 Instrument Cluster.
  7. Verify that a test lamp does not illuminate between the ignition circuit terminal 31 and ground.
    • If the test lamp illuminates 
    1. Disconnect the KR74 Ignition Run Relay
    2. Test for less than 1 V between the ignition circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the KR74 Ignition Run Relay.
    • If the test lamp does not illuminate 
  8. Ignition ON.
  9. Verify that a test lamp illuminates between the ignition terminal 31 and ground.
    • If the test lamp does not illuminate and the Ignition fuse is good 
    1. Ignition OFF, disconnect the KR74 Ignition Run Relay.
    2. Test for less than 2 Ω in the ignition circuit end to end
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the KR74 Ignition Run Relay.
    • If the test lamp does not illuminate and the Ignition fuse is open 
    1. Ignition OFF, disconnect the KR74 Ignition Run Relay.
    2. Test for infinite resistance between the ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the P16 Instrument Cluster.
    • If the test lamp illuminates 
  10. Replace the P16 Instrument Cluster.
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