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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 P135A >> Circuit/System Testing

Circuit/System Testing

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  1. Ignition/Vehicle - Off
  2. Disconnect the electrical connector: X1 @ K20 Engine Control Module
  3. Connect a 3 A fused jumper wire between the test points: Control circuit terminal 1 & Ground
  4. Ignition - On/Vehicle - In Service Mode
  5. Verify a test lamp turns On between the test points: Ignition circuit terminal 16 & Ground
    • If the test lamp does not turn On and the circuit fuse is OK 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Test for less than 2 ohms between the test points: Ignition circuit terminal 16 @ Control module harness & Output terminal @ Fuse
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Verify the fuse is OK and there is voltage at the fuse.
    • If the test lamp does not turn On and the circuit fuse is open 
    1. Ignition/Vehicle - Off
    2. Replace the component: F83UA Fuse
    3. Ignition - On/Vehicle - In Service Mode
    4. Verify the fuse does not open.
      • If the fuse opens and there are components connected to the circuit - Disconnect a component and repeat procedure starting at step 5.1
      • If the fuse opens with all components disconnected from the circuit - Repair the short to ground on the circuit.
      • If the fuse does not open after disconnecting a component from the circuit - Replace the component disconnected last.
      • Go to next step: If the fuse does not open with all components connected, except the following component: K20 Engine Control Module
    5. Ignition/Vehicle - Off
    6. Connect the electrical connector: K20 Engine Control Module
    7. Replace the component: F83UA Fuse
    8. Ignition - On/Vehicle - In Service Mode
    9. Verify the fuse does not open.
      • If the fuse is open - Replace the component: K20 Engine Control Module
      • Go to next step: If the fuse does not open.
      10. NOTE:

      It may be necessary to use a scan tool control function to operate a component.

    10. Operate the component: Each component on the circuit - One at a time

      Verify the fuse does not open when any of the components are activated.

      • If the fuse opens - Replace the component that caused the fuse to open when activated.
      • Go to next step: If the fuse does not open.
    11. All OK.
    • Go to next step: If the test lamp turns On 
  6. Replace the component: K20 Engine Control Module
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