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Home >> Cadillac >> 2021 >> CT4 Sport, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 269 (Exhaust System) >> Diagnostic Information and Procedures >> DTC P2BF8-P2BFA, P316E-P3177, or P3179-P3184 (LT4) >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2022 Cadillac CT5. 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 appropriate electrical connector:
    • {Bank 1 - Passenger Side} M106C Exhaust Control Valve Actuator - Cylinder Deactivation
    • {Bank 2 - Driver Side} M106CB Exhaust Control Valve 2 Actuator - Cylinder Deactivation
  3. Test for less than 10 ohms between the test points: Ground circuit terminal 1 & Ground
    • If 10 ohms or greater 
    1. Disconnect the ground connection: Ground terminal
    2. Test for less than 2 ohms between the test points: Ground circuit terminal 1 @ Component harness & The other end of the circuit @ Ground terminal
      • 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 10 ohms 
  4. Ignition - On / Vehicle - In Service Mode
  5. Verify a test lamp turns On between the test points: Ignition circuit terminal 3 & 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 3 & 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.

        Or

      • If less than 2 ohms - Refer to: Power Mode Mismatch
    • If the test lamp does not turn On and the circuit fuse is open 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Connect the electrical connector: M106 Exhaust Control Valve Actuator
    3. Ignition - On / Vehicle - In Service Mode
    4. Replace the component: Fuse
    5. 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 5.4
      • 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.
      6. NOTE:

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

    6. 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.
    7. All OK.
    • Go to next step: If the test lamp turns On 
  6. Test for 4.8 to 5.2 V between the test points: Signal circuit terminal 4 & Ground
    • If less than 4.8 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K111 Fuel Pump Power Control Module
    3. Test for infinite resistance between the test points: Signal circuit terminal 4 @ 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 4 @ 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: K111 Fuel Pump Power Control Module
    • If greater than 5.2 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K111 Fuel Pump Power Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Signal circuit terminal 4 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K111 Fuel Pump Power Control Module
    • Go to next step: If between 4.8 and 5.2 V 
  7. Test for 5.0 to 6.0 V between the test points: Control circuit terminal 2 & Ground
    • If less than 5.0 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K111 Fuel Pump Power Control Module
    3. Test for infinite resistance between the test points: Control 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: Control 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: K111 Fuel Pump Power Control Module
    • If greater than 6.0 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K111 Fuel Pump Power Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control 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: K111 Fuel Pump Power Control Module
    • Go to next step: If between 5.0 and 6.0 V 
  8. Connect a DMM, set on the voltage setting, between the test points: Control circuit terminal 2 & Ground
  9. Perform the scan tool control function: Cylinder Deactivation Exhaust Control Valve Position @ K20 Engine Control Module - Open/Close

    Verify the DMM value changes when the scan tool control function is commanded.

    • If the value does not change 

      Replace the component: K111 Fuel Pump Power Control Module

    • Go to next step: If the value changes 
  10. Test or replace the component: M106 Exhaust Control Valve Actuator

Test 2

  1. Ignition/Vehicle - Off
  2. Verify a condition does not exist with the component: Linkage @ M106 Exhaust Control Valve Actuator or Valve @ Tail Pipe - Binding or Sticking/Debris/Dirt/Ice or Snow/Interference with other components or objects /Modified/Visible Damage
    • If a condition exists 

      Repair or replace as necessary

    • Go to next step: If no condition exists 
    3. NOTE:

    The learn procedure must be performed if the component has been removed, replaced, or serviced: M106 Exhaust Control Valve Actuator

  3. Remove the appropriate component:
    • {Bank 1 - Passenger Side} M106CB Exhaust Control Valve 2 Actuator - Cylinder Deactivation
    • {Bank 2 - Driver Side} M106C Exhaust Control Valve Actuator - Cylinder Deactivation
  4. Verify the component works as specified: Shaft @ Exhaust Pipe - Rotates freely
    • If the component does not work as specified 
    1. Ignition/Vehicle - Off
    2. Verify a condition does not exist with the component: Valve @ Exhaust Muffler Assembly - Blocked by debris/Casting Flash/Soot Accumulation/Visible Damage
      • If a condition exists - Repair or replace as necessary
      • If no condition exists - Replace the component: Exhaust Muffler Assembly or Tail Pipe
    • Go to next step: If the component works as specified 
  5. Test or replace the component: M106 Exhaust Control Valve Actuator
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