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Tahoe / Yukon Service Manual

DTC P0521, P0522, or P0523 (without LM2)

Diagnostic Instructions Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions DTC Descriptor DTC P0521 Engine Oil Pressure Sensor Performance DTC P0522 Engine Oil Pressure Sensor Circuit Low Voltage DTC P0523 Engine Oil Pressure Sensor Circuit High Voltage Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performanc
5 V Reference P0522 P0522 or 1 P0523 P0521 or 1
Signal P0522 P0522 or 1 P0523 P0521 or 1
Low Reference — P0523 or 1 — P0521 or 1
Low Engine Oil Pressure Indicator = Malfunction

Circuit/System Description For an overview of the component/system, refer to: Instrument Cluster Description and Operation

Circuit Description
5 V Reference Regulated voltage supplied by the control module.
Signal The control module input circuit has an internal resistance connected to ground.
Low Reference Grounded through the control module.
Component Description
B37B Engine Oil Pressure Sensor The sensor is a capacitive pressure transducer. Electronics in the sensor convert pressure into an analog voltage signal.
Component Description
K20 Engine Control Module The K20 control module monitors the B37B Engine Oil Pressure Sensor signal circuit.The control module input circuit has an internal resistance connected to ground.

Conditions for Running the DTC Engine Running Conditions for Setting the DTC P0521 Engine Oil Pressure = The actual value is not within a predetermined range of the calculated value — For greater than 4 s P0522 Engine Oil Pressure Sensor Circuit = Less than 0.2 V — For greater than 10 s P0523 Engine Oil Pressure Sensor Circuit = Greater than 4.8 V — For greater than 10 s Action Taken When the DTC Sets Type C DTC Low Engine Oil Pressure Indicator = On Conditions for Clearing the DTC DTCs listed in the DTC Descriptor category = Type C DTC Reference Information Schematic Reference Instrument Cluster Schematics Connector End View Reference Master Electrical Component List Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs DTC Type Reference Powertrain Diagnostic Trouble Code (DTC) Type Definitions Scan Tool Reference Control Module References

  1. Ignition » On / Vehicle » In Service Mode
  2. Verify the scan tool parameter: Engine Oil Pressure Sensor = 0 kPa (0 PSI) ⇒ If not the specified state Refer to: Circuit/System Testing ⇓ If the specified state
  3. Verify the engine has the correct oil level and the correct oil pressure before continuing with this diagnostic. Displays and Gauges Component Replacement Reference
  4. Engine Running
  5. Verify the scan tool parameter: Engine Oil Pressure Sensor = CH-48027 Digital Pressure Gauge ⇒ If not the specified state Refer to: Circuit/System Testing ⇓ If the specified state
  6. Verify the scan tool parameter: Engine Oil Pressure Sensor = Engine Oil Pressure — Gauge @ P16 Instrument Cluster ⇒ If not the specified state Test or replace the component: P16 Instrument Cluster ⇓ If the specified state
  7. All OK. Circuit/System Testing
  1. Ignition/Vehicle & All vehicle systems » Off
  2. Disconnect the electrical connector: B37B Engine Oil Pressure Sensor
  3. Test for less than 10 Ω between the test points: Low Reference circuit terminal 1 & Ground ⇒ If 10 Ω or greater 3.1. Disconnect the electrical connector: K20 Engine Control Module 3.2. Test for less than 2 Ω between the test points: Low Reference circuit terminal 1 @ Component harness & The other end of the circuit ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Replace the component: K20 Engine Control Module ⇓ If less than 10 Ω
  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 5.1. Ignition/Vehicle » Off 5.2. Disconnect the electrical connector: K20 Engine Control Module 5.3. 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. ⇓ If infinite resistance 5.4. Test for less than 2 Ω between the test points: 5 V Reference circuit terminal 3 @ Component harness & The other end of the circuit ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Replace the component: K20 Engine Control Module ⇒ If greater than 5.2 V 5.1. Ignition/Vehicle » Off 5.2. Disconnect the electrical connector: K20 Engine Control Module 5.3. Ignition » On / Vehicle » In Service Mode 5.4. 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 ⇓ 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) 6.1. Ignition/Vehicle » Off 6.2. Disconnect the electrical connector: K20 Engine Control Module 6.3. Ignition » On / Vehicle » In Service Mode 6.4. 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 ⇓ 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 8.1. Ignition/Vehicle » Off & Remove » Jumper wire(s) 8.2. Disconnect the electrical connector: K20 Engine Control Module 8.3. 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. ⇓ If infinite resistance 8.4. Test for less than 2 Ω between the test points: Signal circuit terminal 2 @ Component harness & The other end of the circuit ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Replace the component: K20 Engine Control Module ⇓ If greater than 800 kPa (116 PSI)
  9. Test or replace the component: B37B Engine Oil Pressure Sensor Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Displays and Gauges Component Replacement Reference For control module replacement, programming, and setup refer to: Control Module References