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Home >> Chevrolet >> 2021 >> Blazer RS, FWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 12 (Engine Controls And Fuel - 2.0L (LSY) - Diagnostic Information And Procedures (2 Of 2)) >> Diagnostic Information and Procedures >> DTC P12A6 >> Circuit/System Testing

Circuit/System Testing

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  1. Ignition/Vehicle - Off
  2. Disconnect the electrical connector: K111 Fuel Pump Driver Control Module
  3. Ignition/Vehicle - On - For greater than 10 s
  4. Verify a test lamp does not turn On between the test points: Control circuit terminal 18 & Ground
    • If the test lamp is always On 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: X1 @ K20 Engine Control Module
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal 18 & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K20 Engine Control Module
    • Go to next step: If the test lamp is always Off 
  5. Remove - Test Lamp
  6. Perform the scan tool control function: Fuel Pump - On
  7. Verify the scan tool parameter: Fuel Pump Enable Circuit Low Voltage Test Status = OK
    • If not the specified state 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: X1 @ K20 Engine Control Module
    3. Test for infinite resistance between the test points: Control circuit terminal 18 & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: K20 Engine Control Module
    • Go to next step: If the specified state 
  8. Connect a 3 A fused jumper wire between the test points: Control circuit terminal 18 & Ground
  9. Verify the scan tool parameter: Fuel Pump Enable Circuit Low Voltage Test Status = Malfunction
    • If not the specified state 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: X1 @ K20 Engine Control Module
    3. Test for less than 2 ohms between the test points: Control circuit terminal 18 & Terminal 17 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K20 Engine Control Module
    • Go to next step: If the specified state 
  10. Replace the component: K111 Fuel Pump Driver Control Module
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