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Home >> GMC >> 2021 >> Terrain SLT, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 91 (Automatic Transmission - 9T45 (M3U) Or 9T50 (M3D M3H) - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC P176B-P176D, P178F, P17C4, or P17D3 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2020 GMC Terrain and 2020 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.
    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: @ B14E Transmission Input/Intermediate Shaft Speed Sensor
  3. Ignition - On / Vehicle - In Service Mode
  4. Test for 8.3 to 9.6 V between the test points: 9 V Reference circuit terminal 2 & Ground
    • If less than 8.3 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K71 Transmission Control Module
    3. Test for infinite resistance between the test points: 9 V Reference 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: 9 V Reference circuit terminal 2 @ Component harness & Terminal 8 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K71 Transmission Control Module
    • If greater than 9.6 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K71 Transmission Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: 9 V Reference 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: K71 Transmission Control Module
    • Go to next step: If between 8.3 and 9.6 V 
  5. Ignition/Vehicle - Off
  6. Install the special tool: EL-38522 Variable Signal Generator
    • Set the voltage to 5 V
    • Set the frequency to 300 Hz
    • Set the duty cycle to 50%
    • Black lead @ Battery Negative Post
    • Red lead @ Signal circuit terminal 1
  7. Ignition - On / Vehicle - In Service Mode
  8. Verify the scan tool parameter: Transmission Intermediate Speed Sensor 313 to 323 RPM
    • If not between 313 and 323 RPM 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K71 Transmission Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Signal circuit terminal 1 @ 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: Signal circuit terminal 1 @ 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: Signal circuit terminal 1 @ Component harness & Terminal 13 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K71 Transmission Control Module
    • Go to next step: If between 313 and 323 RPM 
  9. Test or replace the component: B14E Transmission Input/Intermediate Shaft Speed Sensor
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