LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2021 >> Blazer RS, FWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 10 (Engine Controls And Fuel - 2.0L (LSY) - Diagnostic Information And Procedures (1 Of 2)) >> Diagnostic Information and Procedures >> DTC P0102, P0103, or U060F >> Circuit/System Testing

Circuit/System Testing

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

Test 1

    NOTE:

    It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

  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 4 & Ground
    • If 5 ohms or greater 
    1. Disconnect the ground connection: G116
    2. Test for less than 2 ohms between the test points: Ground circuit terminal 4 @ Component harness & Terminal G116
      • 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. Ignition - On/Vehicle - In Service Mode
  5. Test for 4.8 to 5.2 V between the test points: Signal circuit terminal 2 & Ground
    • If less than 4.8 V 
    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 2 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    4. Test for less than 2 ohms between the test points: Signal circuit terminal 2 @ Component harness & The other end of the circuit @ 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
    • If greater than 5.2 V 
    1. Ignition/Vehicle - Off
    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 2 @ Component harness & 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 between 4.8 and 5.2 V 
  6. Engine - Idling
    7. NOTE:
    • Use the appropriate diagnostic test probe for best results.
    • For this test, the action may need to be repeated several times.
  7. Verify the scan tool parameter: MAF Sensor = Greater than 0 Hz

    Perform the action while monitoring the parameter: Rapidly tap a 3 A fused jumper wire between the test points: Signal circuit terminal 2 & Ground

    • If 0 Hz 

      Replace the component: K20 Engine Control Module

    • Go to next step: If greater than 0 Hz 
  8. Test or replace the component: B75C Multifunction Intake Air Sensor

Test 2

    NOTE:

    It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

  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 4 & Ground
    • If 5 ohms or greater 
    1. Disconnect the ground connection: G116
    2. Test for less than 2 ohms between the test points: Ground circuit terminal 4 @ Component harness & Terminal G116
      • 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. Ignition - On/Vehicle - In Service Mode
  5. Verify a test lamp turns On between the test points: Ignition circuit terminal 1 & 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 1 & 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 & Remove - Test lamp
    2. Ignition - On/Vehicle - In Service Mode
    3. Replace the component: Fuse
    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 5.3
      • 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.
      5. NOTE:

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

    5. 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.
    6. All OK.
    • Go to next step: If the test lamp turns On 
  6. Test for 9 to 11 V between the test points: Serial Data circuit terminal 3 & Ground
    • If less than 9 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the appropriate electrical connector: K20 Engine Control Module
    3. Test for infinite resistance between the test points: Serial Data circuit terminal 3 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    4. Test for less than 2 ohms between the test points: Serial Data circuit terminal 3 @ Component harness & The other end of the circuit @ 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
    • If greater than 11 V 
    1. Ignition/Vehicle - Off
    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: Serial Data circuit terminal 3 @ Component harness & 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 between 9 and 11 V 
  7. Test or replace the component: B75C Multifunction Intake Air Sensor
scientia non olet · About LEMON Manuals