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Home >> Chevrolet >> 2021 >> Blazer RS, FWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 9 (Engine Controls And Fuel - 2.5L (LCV) - Diagnostic Information And Procedures (1 Of 2)) >> Diagnostic Information and Procedures >> DTC P0097-P0099 or P00F4-P00F6 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
    NOTE:

    Circuit/System Verification must be performed before proceeding with Circuit/System Testing.

  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector: B75C Multifunction Intake Air Sensor
  3. Test for less than 5 ohms between the test points: Ground circuit terminal 7 & Ground
    • If 5 ohms or greater 
    1. Disconnect the appropriate ground connection: Chassis Ground
    2. Test for less than 2 ohms between the test points: Ground circuit terminal 7 @ Component harness & The other end of the circuit
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Repair the open/high resistance in the ground connection.
    • Go to next step: If less than 5 ohms 
  4. Verify the scan tool parameter: Intake Air Humidity Sensor = Less than 1%
    • If 1% or greater 
    1. Ignition/Vehicle - Off
    2. Disconnect the appropriate electrical connector: K20 Engine Control Module
    3. Test for infinite resistance between the test points: Signal circuit terminal 8 & 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 less than 1% 
  5. Ignition/Vehicle - Off
  6. Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 8 @ Component harness & Low Reference circuit terminal 3
  7. Ignition - On / Vehicle - In Service Mode
  8. Verify the scan tool parameter: Intake Air Humidity Sensor = Greater than 99%
    • If less than 99% 
      NOTE:

      Internal control module or component damage may occur if the circuit shorts to B+.

    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the appropriate electrical connector: K20 Engine Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Signal circuit terminal 8 & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    5. Ignition/Vehicle - Off
    6. Test for less than 2 ohms between the test points: Signal circuit terminal 8 & The other end of the circuit
      • 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
    • If greater than 99% 
  9. Test or replace the component: B75C Multifunction Intake Air Sensor
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