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Home >> Buick >> 2015 >> Regal GS, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 15 (Engine Controls And Fuel - 2.4L - DTC P0114 To DTC P0604) >> Diagnostic Information and Procedures >> DTC P0121-P0123, P0222, P0223, P16A0-P16A2, or P2135: Throttle Position Sensor >> Circuit/System Testing

Circuit/System Testing

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

    Disconnecting the throttle body harness connector causes additional DTCs to set.

  1. Ignition OFF, and all vehicle systems OFF, disconnect the harness connector at Q38 Throttle Body Assembly. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 5Ω between the low reference circuit terminal 4 and ground.
    • If 5Ω or greater 
    1. Ignition OFF, disconnect the harness connector at the K20 engine Control Module.
    2. Test for less than 2Ω in the low reference circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K20 engine Control Module.
    • If less than 5Ω 
  3. Ignition ON.
  4. Test for 4.8-5.2V between the 5V reference circuit terminal 5 and ground.
    • If less than 4.8V 
    1. Ignition OFF, disconnect the harness connector at the K20 engine Control Module.
    2. Test for infinite resistance between the 5V reference circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2Ω in the 5V reference circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K20 engine Control Module.
    • If greater than 5.2V 
    1. Ignition OFF, disconnect the harness connector at the K20 engine Control Module, ignition ON.
    2. Test for less than 1V between the 5V reference circuit and ground.
      • If 1V or greater, repair the short to voltage on the circuit.
      • If less than 1V, replace the K20 engine Control Module.
    • If between 4.8-5.2V 
  5. Ignition ON.
  6. Test for 4.8-5.2V between the signal circuit terminal 3 and ground.
    • If less than 4.8V 
    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.
      • If infinite resistance
    3. Test for less than 2Ω in the signal circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K20 engine Control Module.
    • If greater than 5.2V 
    1. Ignition OFF, disconnect the harness connector at the K20 engine Control Module, ignition ON.
    2. Test for less than 1V between the signal circuit and ground.
      • If 1V or greater, repair the short to voltage on the circuit.
      • If less than 1V, replace the K20 engine Control Module.
    • If between 4.8-5.2V 
  7. Test or replace the Q38 Throttle Body Assembly.
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