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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 24 (Engine Controls And Fuel - 2.8L (LWN) Diesel - Diagnostic Information And Procedures (1 Of 3)) >> Diagnostic Information and Procedures >> DTC P037A, P037B, or P0381 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
  1. Verify the ignition fuse that supplies voltage to the component is not open : P16 Instrument Cluster
    • If the fuse is open 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector : P16 Instrument Cluster
    3. Test for infinite resistance between the test points : Ignition circuit terminal 19 & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component : P16 Instrument Cluster
    • Go to next step : If the fuse is not open 
  2. Ignition/Vehicle - Off
  3. Disconnect the appropriate electrical connector : K20 Engine Control Module
  4. Ignition - On / Vehicle - In Service Mode
  5. Verify the component works as specified : Wait to Start Indicator = Off
    • If the component does not work as specified 
    1. Ignition/Vehicle - Off
    2. Test for infinite resistance between the test points : Control circuit terminal 19 X1 & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component : P16 Instrument Cluster
    • Go to next step : If the component works as specified 
  6. Ignition/Vehicle - Off
  7. Connect a 3 A fused jumper wire between the test points : Control circuit terminal 19 X1 & Ground
  8. Ignition - On / Vehicle - In Service Mode
  9. Verify the component works as specified : Wait to Start Indicator = On
    • If the component does not work as specified 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the appropriate electrical connector : P16 Instrument Cluster
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points : Control circuit terminal 19 X1 @ Control module 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 less than 2 ohms between the test points : Control circuit terminal 9 @ Component harness & The other end of the circuit @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • Go to next step : If less than 2 ohms
    1. Test for less than 2 ohms between the test points : Ignition circuit terminal 19 @ Component harness & Output terminal @ Fuse
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component : P16 Instrument Cluster
    • Go to next step : If the component works as specified 
  10. Replace the component : K20 Engine Control Module
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