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Home >> Chevrolet >> 2021 >> Blazer RS, FWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 9 (Engine Controls And Fuel - 2.5L (LCV) - Diagnostic Information And Procedures (1 Of 2)) >> Diagnostic Information and Procedures >> DTC P0201-P0204, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P1248, P1249, P124A, P124B, P2147, P2148, P2150, P2151, P2153, P2154, P2156, or P2157 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
  1. Ignition/Vehicle - Off
  2. Disconnect the appropriate electrical connector: Q17 Fuel Injector
  3. Ignition - On / Vehicle - In Service Mode
  4. Test for 5 to 6 V between the test points: Control circuit terminal 2 & Ground
    • If less than 5 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: X2 @ K20 Engine 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 &
      • {Q17A Fuel Injector 1} Terminal 71 @ Control module harness
      • {Q17B Fuel Injector 2} Terminal 68 @ Control module harness
      • {Q17C Fuel Injector 3} Terminal 70 @ Control module harness
      • {Q17D Fuel Injector 4} Terminal 69 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K20 Engine Control Module
    • If greater than 6 V 
    1. Ignition/Vehicle - Off
    2. Test for infinite resistance between the test points: Control circuit terminal 2 & Control circuit terminal 1 @ Component harness
      • If less than infinite resistance - Repair the short between the circuits.
      • Go to next step: If infinite resistance
    3. Disconnect the electrical connector: X2 @ K20 Engine Control Module
    4. Ignition - On / Vehicle - In Service Mode
    5. 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: K20 Engine Control Module
    • Go to next step: If between 5 and 6 V 
  5. Clear the DTCs.
  6. Ignition/Vehicle - Off
  7. Connect a test lamp between the test points: Control circuit terminal 2 & Control circuit terminal 1 @ Q17 Fuel Injector - Component harness
  8. Engine cranking.
  9. Verify the test lamp flashes - For 2 s
    • If the test lamp does not flash 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: X2 @ K20 Engine Control Module
    3. Test for infinite resistance between the test points: Control circuit terminal 1 @ 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 1 @ Component harness &
      • {Q17A Fuel Injector 1} Terminal 51 @ Control module harness
      • {Q17B Fuel Injector 2} Terminal 48 @ Control module harness
      • {Q17C Fuel Injector 3} Terminal 50 @ Control module harness
      • {Q17D Fuel Injector 4} Terminal 49 @ 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
    5. Ignition - On / Vehicle - In Service Mode
    6. Test for less than 1 V between the test points: Control circuit terminal 1 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K20 Engine Control Module
    • Go to next step: If the test lamp flashes 
  10. Test or replace the component: Q17 Fuel Injector
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