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Home >> Chevrolet >> 2021 >> Trailblazer RS, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 11 (Automatic Transmission - VT40 (MRG) - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC P0707, P0708, P2802, P2803, or P2805 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
    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: X1 @ T12 Automatic Transmission Assembly
  3. Test for less than 10 ohms between the test points: Low Reference circuit terminal 16 @ Component harness & Ground
    • If 10 ohms or greater 
    1. Disconnect the electrical connector: K20 Engine Control Module
    2. Test for less than 2 ohms between the test points: Low Reference circuit terminal 16 @ 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
    • Go to next step: If less than 10 ohms 
  4. Ignition - On / Vehicle - In Service Mode
  5. Test for 4.8 to 5.2 V between the test points: 5 V Reference circuit terminal 7 & Ground
    • If less than 4.8 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K20 Engine Control Module
    3. Test for infinite resistance between the test points: 5 V Reference circuit terminal 7 @ 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: 5 V Reference circuit terminal 7 @ 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 electrical connector: K20 Engine Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: 5 V Reference circuit terminal 7 @ 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. Ignition/Vehicle - Off
  7. Install & Setup - EL-38522 Variable Signal Generator
    • Voltage - 5 V
    • Frequency - 120 Hz
    • Duty Cycle - 50%
    • Black lead @ Ground
    • Red lead @
      • {P0707, P0708} Signal circuit terminal 17
      • {P2802, P2803} Signal circuit terminal 19
  8. Ignition - On / Vehicle - In Service Mode
  9. Verify the scan tool parameter:
    • {P0707, P0708} Transmission Range Sensor 1 = 48 to 52%
    • {P2802, P2803} Transmission Range Sensor 2 = 48 to 52%
    • If not in the specified range 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector:
      • {P0707, P0708} K71 Transmission Control Module
      • {P2802, P2803} K20 Engine Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:
      • {P0707, P0708} Signal circuit terminal 17 @ Component harness & Ground
      • {P2802, P2803} Signal circuit terminal 19 @ Component harness & 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 infinite resistance between the test points:
      • {P0707, P0708} Signal circuit terminal 17 @ Component harness & Ground
      • {P2802, P2803} Signal circuit terminal 19 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    7. Test for less than 2 ohms between the test points:
      • {P0707, P0708} Signal circuit terminal 17 @ Component harness & The other end of the circuit @ Control module harness
      • {P2802, P2803} Signal circuit terminal 19 @ 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:
      • {P0707, P0708} K71 Transmission Control Module
      • {P2802, P2803} K20 Engine Control Module
    • Go to next step: If in the specified range 
  10. Connect the electrical connector: X1 @ T12 Automatic Transmission Assembly
  11. Ignition/Vehicle - Off
  12. Remove the component: Automatic Transmission Fluid Pan
  13. Connect the electrical connector: X1 @ T12 Automatic Transmission Assembly
  14. Disconnect the electrical connector: B303 Transmission Range Sensor
  15. Install & Setup - EL-38522 Variable Signal Generator
    • Voltage - 5 V
    • Frequency - 120 Hz
    • Duty Cycle - 50%
    • Black lead @ Ground
    • Red lead @
      • {P0707, P0708} Signal circuit terminal 2
      • {P2802, P2803} Signal circuit terminal 3
  16. Ignition - On / Vehicle - In Service Mode
  17. Verify the scan tool parameter:
    • {P0707, P0708} Transmission Range Sensor 1 = 48 to 52%
    • {P2802, P2803} Transmission Range Sensor 2 = 48 to 52%
    • If not in the specified range 

      Replace the component: Automatic Transmission Wiring Harness

    • Go to next step: If in the specified range 
  18. Test or replace the component: B303 Transmission Range Sensor
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