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Home >> Chevrolet >> 2017 >> Camaro SS, 2D Convertible, Standard Trans >> Repair and Diagnosis >> Engine Mechanical >> Exhaust System >> Diagnostic Information and Procedures >> DTC P26C5: Exhaust Flow Control Valve Control Circuit >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the KR146 Exhaust Flow Control Valve Relay, ignition ON.
  2. 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 good 
    1. Ignition OFF.
    2. 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 not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF.
    2. 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,
    3. Test for greater than 10 Ω between the control circuit terminal 87 and ground.
      • If less than 10 Ω, repair the short to ground in the circuit. If the circuit tests good, replace the Q15 Exhaust Flow Control Valve.
      • If greater than 10 Ω, replace the KR146 Exhaust Flow Control Valve Relay.
    • If the test lamp illuminates 
  3. Verify a test lamp illuminates between the ignition circuit terminal 85 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF.
    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, verify the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF.
    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, test or replace the KR146 Exhaust Flow Control Valve Relay.
    • If the test lamp illuminates 
  4. Connect a test lamp between the ignition circuit terminal 85 and the control circuit terminal 86.
  5. Verify the test lamp turns ON and OFF when commanding the Q15 Exhaust Flow Control Valve OPEN and CLOSED with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the harness connector at the K38 Chassis Control Module, ignition ON.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V
    3. Ignition OFF.
    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 K38 Chassis Control Module.
    • If the test lamp is always ON 
    1. Ignition OFF, disconnect the harness connector at the K38 Chassis Control Module.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K38 Chassis Control Module.
    • If the test lamp turns ON and OFF 
  6. Verify a test lamp does not illuminate between the control circuit terminal 87 and ground.
    • If the test lamp illuminates 

      Repair the short to voltage on the circuit.

    • If the test lamp does not illuminate 
  7. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the Q15 Exhaust Flow Control Valve. It may take up to 2 minutes for all vehicle systems to power down.
  8. Test for less than 10 Ω between the Q15 Exhaust Flow Control Valve ground circuit terminal 1 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF.
    2. 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 
  9. Connect the harness connector at the Q15 Exhaust Flow Control Valve.
  10. Ignition ON, connect a 10 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87.
  11. Verify the Q15 Exhaust Flow Control Valve is activated.
    • If the Q15 Exhaust Flow Control Valve does not activate 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the control circuit terminal 87 end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, test or replace the Q15 Exhaust Flow Control Valve.
    • If the Q15 Exhaust Flow Control Valve activates 
  12. Test or replace the KR146 Exhaust Flow Control Valve Relay.
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