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Home >> Chevrolet >> 2018 >> Equinox L >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 19 (Engine Controls And Fuel - 1.6L (LH7) Diesel - Diagnostic Information And Procedures (P040B - P204D)) >> Diagnostic Information And Procedures >> DTC P204B: Reductant Pressure Sensor Performance >> Circuit/System Testing

Circuit/System Testing

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  1. Ignition Off, disconnect the harness connector at the A38 Reductant Pump and Sensor Assembly.
  2. Ignition On.
  3. Test for less than 10 Ω between the low reference circuit terminal 3 and ground.
    • If 10 Ω or greater 
    1. Ignition Off.
    2. Disconnect the harness connector at the K115 Reductant Control Module.
    3. Test for less than 2 Ω between A38 Reductant Pump and Sensor Assembly harness connector terminal 14 and K115 Reductant Control Module X2 harness connector terminal 3.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K115 Reductant Control Module.
    • Go to next step: If less than 10 Ω 
  4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 5 and ground.
    • If less than 4.8 V 
    1. Ignition Off, disconnect the X2 harness connector at the K115 Reductant Control Module.
    2. Test for less than 2 Ω between A38 Reductant Pump and Sensor Assembly harness connector terminal 5 and K115 Reductant Control Module X2 harness connector terminal 12.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K115 Reductant Control Module.
    • If greater than 5.2 V 
    1. Ignition Off, disconnect the X2 harness connector at the K115 Reductant Control Module, ignition On.
    2. Test for less than 1 V between the A38 Reductant Pump and Sensor Assembly harness connector terminal 5 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K115 Reductant Control Module.
    • Go to next step: If between 4.8 - 5.2 V 
  5. Verify with a scan tool that the Pressure Sensor voltage parameter is 0 V.
    • If greater than 0 V 
    1. Ignition Off, disconnect the X2 harness connector at the K115 Reductant Control Module.
    2. Test for less than 1 V between the A38 Reductant Pump and Sensor Assembly harness connector terminal 4 and ground.
      • If 1 V or greater, repair the short to voltage in the circuit.
      • If less than 1 V, replace the K115 Reductant Control Module.
    • Go to next step: If 0 V 
  6. Install a 3 A fused jumper wire between the between the A38 Reductant Pump and Sensor Assembly harness connector signal circuit terminal 4 and 5 V reference circuit terminal 5. Verify with a scan tool that the Pressure Sensor voltage parameter is greater than 4.5 V
    • If 4.5 V or less 
    1. Ignition Off, remove the jumper wire, disconnect the X2 harness connector at the K115 Reductant Control Module.
    2. Test for infinite resistance between the A38 Reductant Pump and Sensor Assembly signal circuit harness connector terminal 4 and ground.
      • If less than infinite resistance, repair the short to ground at the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω between A38 Reductant Pump and Sensor Assembly harness connector terminal 4 and K115 Reductant Control Module X2 harness connector terminal 13.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K115 Reductant Control Module.
    • If greater than 4.5 V 
  7. Replace the A38 Reductant Pump and Sensor Assembly
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