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HOMESERVICE MANUALSCHEVROLET2020EXPRESS 2500 LS, 2.8L ENG VIN 1REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 102 (ENGINE CONTROLS AND FUEL - 6.0L (L96 LC8) - DIAGNOSTIC INFORMATION AND PROCEDURES (1 OF 2))DIAGNOSTIC INFORMATION AND PROCEDURESDTC P0106CIRCUIT/SYSTEM TESTING
2020 Chevrolet Express 2500 LS, 2.8L Eng VIN 1

Circuit/System Testing

2020 Chevrolet Express 2500 LS, 2.8L Eng VIN 1SECTION Circuit/System Testing
WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
  1. Verify the integrity of the entire air induction system and verify that none of the following conditions exist:
    • Any damaged components
    • Improper operation of turbocharger wastegate actuator or bypass valve, if equipped
    • Loose or improper installation of the turbocharger and the charge air cooler, including the flexible ductwork, if equipped
    • An air flow restriction
    • Any vacuum leak
    • Improperly routed vacuum hoses
    • In cold climates, inspect for any snow or ice buildup at the BARO port on the ECM, if equipped
    • A restriction in the MAP Sensor port or the BARO port, if equipped
    • Proper operation of the Positive Crankcase Ventilation (PCV) system
    • Missing, restricted or leaking exhaust components. Refer to Restricted Exhaust .
    • Engine mechanical condition, for example: low compression or incorrect timing chain installation. Refer to Symptoms - Engine Mechanical
    • If a condition is found 

      Repair or replace the component as appropriate.

    • Go to next step: If no condition is found 
  2. Ignition OFF and all vehicle systems OFF. It may take up to 2 min for all vehicle systems to power down. Disconnect the B74 Manifold Absolute Pressure Sensor.
  3. Test for less than 5 Ω between the low reference circuit terminal 2 and ground.
    • If 5 Ω or greater 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for less than 2 Ω in the low reference 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.
    • Go to next step: If less than 5 Ω 
  4. Ignition ON.
  5. Test for 4. 8 - 5. 2 V between the 5 V reference circuit terminal 1 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 5 V reference 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 5 V reference 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.
      NOTE:

      If the signal circuit is shorted to a voltage the ECM or the MAP Sensor may be damaged.

    • 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 5 V reference 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. Verify the scan tool MAP Sensor parameter is less than 0. 5 V.
    • If 0. 5 V or greater 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
    2. Test for less than 1 V between the signal circuit terminal 3 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 less than 0. 5 V 
  7. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the 5 V reference circuit terminal 1.
  8. Verify the scan tool MAP Sensor parameter is greater than 4. 5 V.
    • If 4. 5 V or less 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the signal circuit terminal 3 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.
    • Go to next step: If greater than 4. 5 V 
  9. Test or replace the B74 Manifold Absolute Pressure Sensor.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.