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Home >> Chevrolet >> 2023 >> Tahoe SSV >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Instrument Panel, Displays And Gauges >> Diagnostic Information and Procedures >> DTC P0521, P0522, or P0523 >> Circuit/System Testing

Circuit/System Testing

    NOTE:

    It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector: B37B Engine Oil Pressure Sensor
  3. Test for less than 10 ohms between the test points: Low Reference circuit terminal 1 & Ground
    • If 10 ohms or greater 
    1. Disconnect the electrical connector: K20 Engine Control Module
    2. Test for less than 2 ohms between the test points: Low Reference circuit terminal 1@Component harness & The other end of the circuit
      • 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
    • Go to next step: If less than 10 ohms  
  4. Ignition - On / Vehicle - In Service Mode
  5. Test for 4.8 to 5.2 V between the test points: 5 V Reference circuit terminal 3 & Low Reference circuit terminal 1
    • If less than 4.8 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector:K20 Engine Control Module
    3. Test for infinite resistance between the test points: 5 V Reference circuit terminal 3@ 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: 5 V Reference circuit terminal 3@ Component harness & The other end of the circuit
      • 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 5.2 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector:K20 Engine Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:5 V Reference circuit terminal 3@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 4.8 and 5.2 V 
  6. Verify the scan tool parameter:Engine Oil Pressure Sensor =0 kPa (0 PSI)
    • If greater than 0 kPa (0 PSI) 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector:K20 Engine Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:Signal 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 0 kPa (0 PSI) or less 
  7. Connect a 3 A fused jumper wire between the test points:Signal circuit terminal 2 & 5 V Reference circuit terminal 3
  8. Verify the scan tool parameter:Engine Oil Pressure Sensor =Greater than 800 kPa (116 PSI)
    • If 800 kPa (116 PSI) or less 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector:K20 Engine Control Module
    3. Test for infinite resistance between the test points:Signal 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:Signal circuit terminal 2@Component harness & The other end of the circuit
      • 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
    • Go to next step: If greater than 800 kPa (116 PSI) 
  9. Test or replace the component:B37B Engine Oil Pressure Sensor


NOTE:

Circuit/System Verification must be performed before proceeding with Circuit/System Testing.

  1. Ignition OFF/Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the B37B Engine Oil Pressure Sensor. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 15 Ω between the low reference circuit terminal 2 and ground.
    • If 15 Ω or greater 
    1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for less than 2 Ω in the low reference circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K20 Engine Control Module.
    • Go to next step: If less than 15 Ω 
  3. Ignition ON/Vehicle in Service Mode.
  4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 3 and ground.
    • If less than 4.8 V 
    1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the 5 V reference circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω in the 5 V reference circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K20 Engine Control Module.
    • If greater than 5.2 V 
    1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
    2. Test for less than 1 V between the 5 V reference circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K20 Engine Control Module.
    • Go to next step: If between 4.8 - 5.2 V 
  5. Verify the scan tool Engine Oil Pressure parameter is less than 14 kPa (2 psi).
    • If 14 kPa (2 psi) or above 
    1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
    2. Test for less than 1 V between the signal circuit terminal 1 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K20 Engine Control Module.
    • Go to next step: If below 14 kPa (2 psi) 
  6. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the 5 V reference circuit terminal 3.
  7. Engine running.
  8. Verify the scan tool Engine Oil Pressure parameter is greater than 800kPa (116psi).
    • If 800kPa (116psi) or less 
    1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the signal circuit terminal 1 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω in the signal circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K20 Engine Control Module.
    • Go to next step: If greater than 800kPa (116psi) 
  9. Test or replace the B37B Engine Oil Pressure Sensor.
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