LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2024 >> Tahoe Commercial, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 9 (Engine Controls And Fuel - 3.0L (Lm2) Diesel - Diagnostic Information And Procedures (3 Of 5)) >> Diagnostic Information and Procedures >> DTC P066A-P066F, P0671-P0676, or P067A-P067F >> Circuit/System Testing - Test 1

Circuit/System Testing - Test 1

WARNING: This page is about a different variant/trim than selected.
  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector: X1 @ K20 Engine Control Module
  3. Test for battery voltage between the test points: B+ circuit terminal 1 & Ground
    • If less than battery voltage 
    1. Test for less than 2 ohms between the test points:
      • {Cadillac}B+ circuit terminal 1 & Output terminal @F5UD Fuse
      • {Chevrolet/GMC}B+ circuit terminal 1 & Output terminal @F5BA Fuse
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • Go to next step: If less than 2 ohms
    2. Test for infinite resistance between the test points: B+ circuit terminal 1 & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Verify the fuse is OK and there is voltage at the fuse.
      • If a condition exists - Repair or replace as necessary
      • If no condition exists - Replace the component: K20 Engine Control Module
    • Go to next step: If battery voltage 
  4. Connect a DMM between the test points: B+ circuit terminal 1 & Ground
  5. Verify the DMM displays the following: Battery Voltage = The value should not spike or drop out.

    Perform the action while monitoring the DMM:

    • {Cadillac}Wiggle the harness and connector(s): X9 - A@X50B Battery Distribution Engine Compartment Fuse Block
    • {Chevrolet/GMC}Wiggle the harness and connector(s): X5 - A@X50B Battery Distribution Engine Compartment Fuse Block
    • If the value spikes or drops out 

      Repair as necessary - Wiring/Terminal(s)/Electrical Connector(s)/Fuse

    • Go to next step: If the value does not spike or drop out 
  6. Replace the component: K20 Engine Control Module