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Home / DTC / P0520 — Engine Oil Pressure Sensor/Switch A Circuit

P0520 — Engine Oil Pressure Sensor/Switch A Circuit

Detailed page for trouble code P0520.

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P0520

Generic P — Powertrain

Engine Oil Pressure Sensor/Switch A Circuit

Brand: Generic
Type: P — Powertrain
Views: UK: 23 EN: 30 RU: 37
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or shorted wiring between the oil pressure sensor and PCM
  • Corroded, loose, or damaged sensor connector pins
  • Failed oil pressure sensor or switch
  • Poor sensor ground or reference voltage (blown fuse, bad ground, low battery voltage)
  • Intermittent connection (broken wire, damaged insulation)
  • PCM input circuit fault (rare)

Symptoms

  • Check Engine Light (MIL) illuminated
  • Oil pressure warning light or message (may be separate) or erroneous oil pressure gauge reading
  • Incorrect or fluctuating oil pressure readings on scan tool
  • Possible drivability concerns if vehicle enters limp mode (manufacturer dependent)
  • Engine may run normally but with risk of undetected low oil pressure

What to check

  • Verify engine oil level and condition (do not assume electrical fault if oil is very low)
  • Scan for stored and pending codes and note freeze-frame data
  • Visual inspection of oil pressure sensor, connector, and wiring for damage, corrosion, or oil intrusion
  • Check for blown fuses and battery/system voltage stability
  • Backprobe sensor connector to measure reference voltage, signal voltage, and ground
  • Compare electronic oil pressure reading to a mechanical gauge to rule out mechanical pressure issues

Signal parameters

  • Typical sensor types: variable voltage pressure sensor (analog) or pressure-switch (open/closed).
  • Common analog range: ~0.5–4.5 V (0 psi to high pressure) with a 5 V reference from PCM (varies by manufacturer).
  • Switch type: continuity to ground or to battery voltage when pressure crosses threshold.
  • At key ON/engine OFF the signal may read near a predefined voltage (varies by design); on running engine signal should change with rpm/pressure.
  • Reference circuit: 5 V supply (check for ~5 V at reference pin). Ground circuit: near 0 Ω to chassis.

Diagnostic algorithm

  1. Safety first: Park on level surface, set parking brake, engine off and cool. Use PPE and secure vehicle.
  2. Retrieve DTCs and freeze-frame data with a scan tool. Note when fault set (idle, start, warm, cold).
  3. Visually inspect sensor and harness for oil contamination, corrosion, broken wires, or connector damage. Repair obvious damage.
  4. Check engine oil level and top to correct level if low; re-check for codes after driving if oil was low.
  5. With ignition ON (engine OFF), backprobe sensor connector: verify 5 V reference (if used) and good ground. If no reference, trace/fuse to PCM.
  6. Start engine and observe signal voltage while increasing RPM. Signal should change smoothly with rpm/pressure. Look for open circuit (no change) or stuck/erratic readings.
  7. Wiggle test wiring and connectors while monitoring signal for intermittent behavior. Repair any intermittent wiring faults.
  8. Measure resistance/continuity between sensor ground and chassis ground; repair poor grounds.
  9. If the harness and power/ground are good, compare electronic reading to a mechanical oil pressure gauge to exclude internal engine oil pressure problems.
  10. If sensor wiring checks good and mechanical pressure is normal, replace the oil pressure sensor/switch. Clear codes and road test to confirm repair.
  11. If code returns after replacing sensor and repairing harness, check PCM input circuits and grounds. Consider PCM diagnostics or replacement only after exhaustive wiring/sensor verification.

Likely causes

  • Faulty oil pressure sensor/switch
  • Corroded/loose connector at the sensor
  • Broken or shorted harness (chafing, pinched, rodent damage)
  • Bad ground or missing 5V reference from PCM
  • Blown fuse or low system voltage affecting sensor circuit

Fault status

⚠️ Status
P0520 - Engine Oil Pressure Sensor/Switch A Circuit. MIL ON. Circuit open/short/intermittent detected in oil pressure sensor input.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5–2.0 hours

Similar codes

P0521 P0522 P0523 P0524 P0562
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Code

P0520

GWM P — Powertrain

- Oil pressure sensor circuit fault

Brand: GWM
Type: P — Powertrain
Views: UK: 4 EN: 2 RU: 9
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or shorted wiring between the oil pressure sensor and PCM
  • Corroded, loose, or damaged sensor connector pins
  • Failed oil pressure sensor or switch
  • Poor sensor ground or reference voltage (blown fuse, bad ground, low battery voltage)
  • Intermittent connection (broken wire, damaged insulation)
  • PCM input circuit fault (rare)

Symptoms

  • Check Engine Light (MIL) illuminated
  • Oil pressure warning light or message (may be separate) or erroneous oil pressure gauge reading
  • Incorrect or fluctuating oil pressure readings on scan tool
  • Possible drivability concerns if vehicle enters limp mode (manufacturer dependent)
  • Engine may run normally but with risk of undetected low oil pressure

What to check

  • Verify engine oil level and condition (do not assume electrical fault if oil is very low)
  • Scan for stored and pending codes and note freeze-frame data
  • Visual inspection of oil pressure sensor, connector, and wiring for damage, corrosion, or oil intrusion
  • Check for blown fuses and battery/system voltage stability
  • Backprobe sensor connector to measure reference voltage, signal voltage, and ground
  • Compare electronic oil pressure reading to a mechanical gauge to rule out mechanical pressure issues

Signal parameters

  • Typical sensor types: variable voltage pressure sensor (analog) or pressure-switch (open/closed).
  • Common analog range: ~0.5–4.5 V (0 psi to high pressure) with a 5 V reference from PCM (varies by manufacturer).
  • Switch type: continuity to ground or to battery voltage when pressure crosses threshold.
  • At key ON/engine OFF the signal may read near a predefined voltage (varies by design); on running engine signal should change with rpm/pressure.
  • Reference circuit: 5 V supply (check for ~5 V at reference pin). Ground circuit: near 0 Ω to chassis.

Diagnostic algorithm

  1. Safety first: Park on level surface, set parking brake, engine off and cool. Use PPE and secure vehicle.
  2. Retrieve DTCs and freeze-frame data with a scan tool. Note when fault set (idle, start, warm, cold).
  3. Visually inspect sensor and harness for oil contamination, corrosion, broken wires, or connector damage. Repair obvious damage.
  4. Check engine oil level and top to correct level if low; re-check for codes after driving if oil was low.
  5. With ignition ON (engine OFF), backprobe sensor connector: verify 5 V reference (if used) and good ground. If no reference, trace/fuse to PCM.
  6. Start engine and observe signal voltage while increasing RPM. Signal should change smoothly with rpm/pressure. Look for open circuit (no change) or stuck/erratic readings.
  7. Wiggle test wiring and connectors while monitoring signal for intermittent behavior. Repair any intermittent wiring faults.
  8. Measure resistance/continuity between sensor ground and chassis ground; repair poor grounds.
  9. If the harness and power/ground are good, compare electronic reading to a mechanical oil pressure gauge to exclude internal engine oil pressure problems.
  10. If sensor wiring checks good and mechanical pressure is normal, replace the oil pressure sensor/switch. Clear codes and road test to confirm repair.
  11. If code returns after replacing sensor and repairing harness, check PCM input circuits and grounds. Consider PCM diagnostics or replacement only after exhaustive wiring/sensor verification.

Likely causes

  • Faulty oil pressure sensor/switch
  • Corroded/loose connector at the sensor
  • Broken or shorted harness (chafing, pinched, rodent damage)
  • Bad ground or missing 5V reference from PCM
  • Blown fuse or low system voltage affecting sensor circuit

Fault status

⚠️ Status
P0520 - Engine Oil Pressure Sensor/Switch A Circuit. MIL ON. Circuit open/short/intermittent detected in oil pressure sensor input.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5–2.0 hours

Similar codes

P0521 P0522 P0523 P0524 P0562
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P0520

HUMMER P — Powertrain

Engine Oil Pressure Sensor/Switch Circuit Malfunction

Brand: HUMMER
Type: P — Powertrain
Views: UK: 11 EN: 17 RU: 24
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or shorted wiring between the oil pressure sensor and PCM
  • Corroded, loose, or damaged sensor connector pins
  • Failed oil pressure sensor or switch
  • Poor sensor ground or reference voltage (blown fuse, bad ground, low battery voltage)
  • Intermittent connection (broken wire, damaged insulation)
  • PCM input circuit fault (rare)

Symptoms

  • Check Engine Light (MIL) illuminated
  • Oil pressure warning light or message (may be separate) or erroneous oil pressure gauge reading
  • Incorrect or fluctuating oil pressure readings on scan tool
  • Possible drivability concerns if vehicle enters limp mode (manufacturer dependent)
  • Engine may run normally but with risk of undetected low oil pressure

What to check

  • Verify engine oil level and condition (do not assume electrical fault if oil is very low)
  • Scan for stored and pending codes and note freeze-frame data
  • Visual inspection of oil pressure sensor, connector, and wiring for damage, corrosion, or oil intrusion
  • Check for blown fuses and battery/system voltage stability
  • Backprobe sensor connector to measure reference voltage, signal voltage, and ground
  • Compare electronic oil pressure reading to a mechanical gauge to rule out mechanical pressure issues

Signal parameters

  • Typical sensor types: variable voltage pressure sensor (analog) or pressure-switch (open/closed).
  • Common analog range: ~0.5–4.5 V (0 psi to high pressure) with a 5 V reference from PCM (varies by manufacturer).
  • Switch type: continuity to ground or to battery voltage when pressure crosses threshold.
  • At key ON/engine OFF the signal may read near a predefined voltage (varies by design); on running engine signal should change with rpm/pressure.
  • Reference circuit: 5 V supply (check for ~5 V at reference pin). Ground circuit: near 0 Ω to chassis.

Diagnostic algorithm

  1. Safety first: Park on level surface, set parking brake, engine off and cool. Use PPE and secure vehicle.
  2. Retrieve DTCs and freeze-frame data with a scan tool. Note when fault set (idle, start, warm, cold).
  3. Visually inspect sensor and harness for oil contamination, corrosion, broken wires, or connector damage. Repair obvious damage.
  4. Check engine oil level and top to correct level if low; re-check for codes after driving if oil was low.
  5. With ignition ON (engine OFF), backprobe sensor connector: verify 5 V reference (if used) and good ground. If no reference, trace/fuse to PCM.
  6. Start engine and observe signal voltage while increasing RPM. Signal should change smoothly with rpm/pressure. Look for open circuit (no change) or stuck/erratic readings.
  7. Wiggle test wiring and connectors while monitoring signal for intermittent behavior. Repair any intermittent wiring faults.
  8. Measure resistance/continuity between sensor ground and chassis ground; repair poor grounds.
  9. If the harness and power/ground are good, compare electronic reading to a mechanical oil pressure gauge to exclude internal engine oil pressure problems.
  10. If sensor wiring checks good and mechanical pressure is normal, replace the oil pressure sensor/switch. Clear codes and road test to confirm repair.
  11. If code returns after replacing sensor and repairing harness, check PCM input circuits and grounds. Consider PCM diagnostics or replacement only after exhaustive wiring/sensor verification.

Likely causes

  • Faulty oil pressure sensor/switch
  • Corroded/loose connector at the sensor
  • Broken or shorted harness (chafing, pinched, rodent damage)
  • Bad ground or missing 5V reference from PCM
  • Blown fuse or low system voltage affecting sensor circuit

Fault status

⚠️ Status
P0520 - Engine Oil Pressure Sensor/Switch A Circuit. MIL ON. Circuit open/short/intermittent detected in oil pressure sensor input.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5–2.0 hours

Similar codes

P0521 P0522 P0523 P0524 P0562
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P0520

LAND ROVER P — Powertrain

Engine oil pressure sensor / circuit malfunction switch

Brand: LAND ROVER
Type: P — Powertrain
Views: UK: 7 EN: 8 RU: 16
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or shorted wiring between the oil pressure sensor and PCM
  • Corroded, loose, or damaged sensor connector pins
  • Failed oil pressure sensor or switch
  • Poor sensor ground or reference voltage (blown fuse, bad ground, low battery voltage)
  • Intermittent connection (broken wire, damaged insulation)
  • PCM input circuit fault (rare)

Symptoms

  • Check Engine Light (MIL) illuminated
  • Oil pressure warning light or message (may be separate) or erroneous oil pressure gauge reading
  • Incorrect or fluctuating oil pressure readings on scan tool
  • Possible drivability concerns if vehicle enters limp mode (manufacturer dependent)
  • Engine may run normally but with risk of undetected low oil pressure

What to check

  • Verify engine oil level and condition (do not assume electrical fault if oil is very low)
  • Scan for stored and pending codes and note freeze-frame data
  • Visual inspection of oil pressure sensor, connector, and wiring for damage, corrosion, or oil intrusion
  • Check for blown fuses and battery/system voltage stability
  • Backprobe sensor connector to measure reference voltage, signal voltage, and ground
  • Compare electronic oil pressure reading to a mechanical gauge to rule out mechanical pressure issues

Signal parameters

  • Typical sensor types: variable voltage pressure sensor (analog) or pressure-switch (open/closed).
  • Common analog range: ~0.5–4.5 V (0 psi to high pressure) with a 5 V reference from PCM (varies by manufacturer).
  • Switch type: continuity to ground or to battery voltage when pressure crosses threshold.
  • At key ON/engine OFF the signal may read near a predefined voltage (varies by design); on running engine signal should change with rpm/pressure.
  • Reference circuit: 5 V supply (check for ~5 V at reference pin). Ground circuit: near 0 Ω to chassis.

Diagnostic algorithm

  1. Safety first: Park on level surface, set parking brake, engine off and cool. Use PPE and secure vehicle.
  2. Retrieve DTCs and freeze-frame data with a scan tool. Note when fault set (idle, start, warm, cold).
  3. Visually inspect sensor and harness for oil contamination, corrosion, broken wires, or connector damage. Repair obvious damage.
  4. Check engine oil level and top to correct level if low; re-check for codes after driving if oil was low.
  5. With ignition ON (engine OFF), backprobe sensor connector: verify 5 V reference (if used) and good ground. If no reference, trace/fuse to PCM.
  6. Start engine and observe signal voltage while increasing RPM. Signal should change smoothly with rpm/pressure. Look for open circuit (no change) or stuck/erratic readings.
  7. Wiggle test wiring and connectors while monitoring signal for intermittent behavior. Repair any intermittent wiring faults.
  8. Measure resistance/continuity between sensor ground and chassis ground; repair poor grounds.
  9. If the harness and power/ground are good, compare electronic reading to a mechanical oil pressure gauge to exclude internal engine oil pressure problems.
  10. If sensor wiring checks good and mechanical pressure is normal, replace the oil pressure sensor/switch. Clear codes and road test to confirm repair.
  11. If code returns after replacing sensor and repairing harness, check PCM input circuits and grounds. Consider PCM diagnostics or replacement only after exhaustive wiring/sensor verification.

Likely causes

  • Faulty oil pressure sensor/switch
  • Corroded/loose connector at the sensor
  • Broken or shorted harness (chafing, pinched, rodent damage)
  • Bad ground or missing 5V reference from PCM
  • Blown fuse or low system voltage affecting sensor circuit

Fault status

⚠️ Status
P0520 - Engine Oil Pressure Sensor/Switch A Circuit. MIL ON. Circuit open/short/intermittent detected in oil pressure sensor input.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5–2.0 hours

Similar codes

P0521 P0522 P0523 P0524 P0562
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Code

P0520

MERCEDES-BENZ P — Powertrain

Engine Oil Pressure Sensor/Switch Circuit Malfunction

Brand: MERCEDES-BENZ
Type: P — Powertrain
Views: UK: 12 EN: 19 RU: 26
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or shorted wiring between the oil pressure sensor and PCM
  • Corroded, loose, or damaged sensor connector pins
  • Failed oil pressure sensor or switch
  • Poor sensor ground or reference voltage (blown fuse, bad ground, low battery voltage)
  • Intermittent connection (broken wire, damaged insulation)
  • PCM input circuit fault (rare)

Symptoms

  • Check Engine Light (MIL) illuminated
  • Oil pressure warning light or message (may be separate) or erroneous oil pressure gauge reading
  • Incorrect or fluctuating oil pressure readings on scan tool
  • Possible drivability concerns if vehicle enters limp mode (manufacturer dependent)
  • Engine may run normally but with risk of undetected low oil pressure

What to check

  • Verify engine oil level and condition (do not assume electrical fault if oil is very low)
  • Scan for stored and pending codes and note freeze-frame data
  • Visual inspection of oil pressure sensor, connector, and wiring for damage, corrosion, or oil intrusion
  • Check for blown fuses and battery/system voltage stability
  • Backprobe sensor connector to measure reference voltage, signal voltage, and ground
  • Compare electronic oil pressure reading to a mechanical gauge to rule out mechanical pressure issues

Signal parameters

  • Typical sensor types: variable voltage pressure sensor (analog) or pressure-switch (open/closed).
  • Common analog range: ~0.5–4.5 V (0 psi to high pressure) with a 5 V reference from PCM (varies by manufacturer).
  • Switch type: continuity to ground or to battery voltage when pressure crosses threshold.
  • At key ON/engine OFF the signal may read near a predefined voltage (varies by design); on running engine signal should change with rpm/pressure.
  • Reference circuit: 5 V supply (check for ~5 V at reference pin). Ground circuit: near 0 Ω to chassis.

Diagnostic algorithm

  1. Safety first: Park on level surface, set parking brake, engine off and cool. Use PPE and secure vehicle.
  2. Retrieve DTCs and freeze-frame data with a scan tool. Note when fault set (idle, start, warm, cold).
  3. Visually inspect sensor and harness for oil contamination, corrosion, broken wires, or connector damage. Repair obvious damage.
  4. Check engine oil level and top to correct level if low; re-check for codes after driving if oil was low.
  5. With ignition ON (engine OFF), backprobe sensor connector: verify 5 V reference (if used) and good ground. If no reference, trace/fuse to PCM.
  6. Start engine and observe signal voltage while increasing RPM. Signal should change smoothly with rpm/pressure. Look for open circuit (no change) or stuck/erratic readings.
  7. Wiggle test wiring and connectors while monitoring signal for intermittent behavior. Repair any intermittent wiring faults.
  8. Measure resistance/continuity between sensor ground and chassis ground; repair poor grounds.
  9. If the harness and power/ground are good, compare electronic reading to a mechanical oil pressure gauge to exclude internal engine oil pressure problems.
  10. If sensor wiring checks good and mechanical pressure is normal, replace the oil pressure sensor/switch. Clear codes and road test to confirm repair.
  11. If code returns after replacing sensor and repairing harness, check PCM input circuits and grounds. Consider PCM diagnostics or replacement only after exhaustive wiring/sensor verification.

Likely causes

  • Faulty oil pressure sensor/switch
  • Corroded/loose connector at the sensor
  • Broken or shorted harness (chafing, pinched, rodent damage)
  • Bad ground or missing 5V reference from PCM
  • Blown fuse or low system voltage affecting sensor circuit

Fault status

⚠️ Status
P0520 - Engine Oil Pressure Sensor/Switch A Circuit. MIL ON. Circuit open/short/intermittent detected in oil pressure sensor input.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5–2.0 hours

Similar codes

P0521 P0522 P0523 P0524 P0562
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