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Home >> GMC >> 2018 >> Acadia Denali, FWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 11 (Engine Controls And Fuel - 2.5L (LCV) - Diagnostic Information And Procedures (P0010 - P034B)) >> Diagnostic Information And Procedures >> DTC P0101: Mass Air Flow (MAF) Sensor Performance >> Circuit/System Testing

Circuit/System Testing

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

You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

  1. Verify the integrity of the entire air induction system by verifying that none of the following conditions exist:
    • Any damaged components
    • Improperly installed components
    • Collapsed, restricted, or damaged components
    • Loose clamps, cracks, or other damage
    • An air flow restriction
    • Improper operation of the positive crankcase ventilation system
    • Restricted air filter
    • Splits, kinks, leaks, or improper connections at the vacuum hoses
    • Vacuum leaks at the intake manifold, MAP sensor, and throttle body
    • Water intrusion
    • Any snow or ice buildup, in cold climates
    • Contamination of the Multifunction Intake Air sensor element
    • If a condition is found 

      Repair or replace component as appropriate.

    • Go to next step: If no condition is found 
  2. Ignition OFF, disconnect the harness connector at the B75C Multifunction Intake Air sensor.
  3. Ignition OFF and all systems OFF. It may take up to for 2 minutes for all vehicle systems to power down. Test for less than 5 Ω between the ground circuit terminal 7 and ground.
    • If 5 Ω or greater 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • Go to next step: If less than 5 Ω 
  4. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 5 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF, remove the test lamp and remove the fuse for the ignition voltage circuit.
    2. Test for less than 2 Ω in the ignition voltage circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF, remove the test lamp and remove the fuse for the ignition voltage circuit.
    2. Test for infinite resistance between the ignition voltage circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, test all components connected to the ignition circuit, replace as necessary.
    • Go to next step: If a test lamp illuminates 
  5. Ignition ON, test for 4.8 - 5.2 volts between the signal circuit terminal 6 and ground.
    • If less than 4.8 V 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the signal circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω in the signal circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K20 Engine Control Module.
    • If greater than 5.2 V 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Ignition ON, test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K20 Engine Control Module.
    • Go to next step: If between 4.8 - 5.2 V 
  6. Ignition OFF, connect the leads of the EL-38522  Variable Signal Generator as follows:
    • Red lead to the signal circuit terminal 6 at the harness connector
    • Black leads to ground
    • Battery voltage supply lead to B+
  7. Set the EL-38522  Variable Signal Generator to the following specifications.
    • Signal switch to 5 V
    • Frequency switch to 5 kHz
    • Duty Cycle switch to 50% (Normal)
  8. Engine idling, observe the scan tool MAF Sensor parameter. The scan tool MAF Sensor parameter should be between 4950 - 5050 Hz.
    • If not between 4950 - 5050 Hz. 

      If not between 4950 - 5050 Hz, replace the K20 Engine Control Module.

    • Go to next step: If between 4950 - 5050 Hz. 
  9. Test or replace the B75C Multifunction Intake Air sensor.
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