Faulty engine oil pressure sensor or sender (both sources). Wiring issue, such as excessive resistance or a short in the circuit between the sensor, the PCM and ground (both sources; OBD-Codes.com gives the detail). Less often: PCM failure (both sources). Low engine oil or an oil leak can cause low pressure and turn on the oil light, so OBD-Codes.com says to check the oil level first.

Top up or repair the cause of low oil if the level was low, then recheck (OBD-Codes.com). Repair damaged wiring or a bad connector in the oil pressure sensor circuit (both sources). Replace a faulty oil pressure sensor (RepairPal lists oil pressure sensor replacement as the common repair). Replace or reprogram the PCM only as a last resort after proper diagnosis (OBD-Codes.com).

P0520🔧 Engine lubrication / oil pressure sensorStop and fix promptly

P0520: Oil Pressure Sensor Circuit (Meaning, Causes, Fixes)

Q: What does P0520 mean?

P0520 means the engine computer is getting a signal from the oil pressure sensor (or sender/switch) that's out of its normal range. OBD-Codes.com says the cause is most likely electrical, usually a bad sensor or a wiring problem, but the first check is always the oil level, because low oil can also turn on the oil light. Don't assume it's just the sensor until you know the engine has oil and pressure. The oil pressure sensor, also called a sender or switch, measures the engine's mechanical oil pressure and reports it to the powertrain control module (PCM) as a voltage. Depending on the vehicle, that value drives an oil pressure gauge or just a warning light on the dash. P0520 sets when the PCM sees a value from the sensor that is out of its normal range, which RepairPal describes as an incorrect signal from the sensor. OBD-Codes.com calls it a generic code for 1996-and-newer vehicles, says it shows up more often on Chevrolet, Dodge, GMC, Mercedes-Benz, Pontiac and Cadillac models, and lists P0521, P0522, P0523 and P0524 as related codes. P0520 is a circuit code, which is different from P0524 (engine oil pressure too low), where the engine computer believes actual oil pressure is low. The two sources agree the usual culprits are the sensor and its wiring, with the PCM a less likely cause. OBD-Codes.com also mentions a Dodge-Chrysler-Ram-Jeep technical service bulletin (18-034-14) related to this code.

Q: Can I keep driving with P0520?

Stop and fix promptly. RepairPal puts P0520 in its urgent category, meaning action is needed right away because it can cause severe damage or put the people in the car at risk. OBD-Codes.com says the cause is most likely electrical, but the same symptoms can come from a real oil pressure problem, and an engine run without oil pressure can be ruined in minutes. If the red oil pressure light is on or the gauge reads low, pull over safely, shut the engine off and check the oil level before driving any further. If you can't confirm the engine has oil and real oil pressure, have it towed.

Reviewed 2026-10-22 · Based on 2 cited source(s)

What P0520 means

The oil pressure sensor, also called a sender or switch, measures the engine's mechanical oil pressure and reports it to the powertrain control module (PCM) as a voltage. Depending on the vehicle, that value drives an oil pressure gauge or just a warning light on the dash. P0520 sets when the PCM sees a value from the sensor that is out of its normal range, which RepairPal describes as an incorrect signal from the sensor. OBD-Codes.com calls it a generic code for 1996-and-newer vehicles, says it shows up more often on Chevrolet, Dodge, GMC, Mercedes-Benz, Pontiac and Cadillac models, and lists P0521, P0522, P0523 and P0524 as related codes. P0520 is a circuit code, which is different from P0524 (engine oil pressure too low), where the engine computer believes actual oil pressure is low. The two sources agree the usual culprits are the sensor and its wiring, with the PCM a less likely cause. OBD-Codes.com also mentions a Dodge-Chrysler-Ram-Jeep technical service bulletin (18-034-14) related to this code.

Severity: can I keep driving?

Stop and fix promptly

RepairPal puts P0520 in its urgent category, meaning action is needed right away because it can cause severe damage or put the people in the car at risk. OBD-Codes.com says the cause is most likely electrical, but the same symptoms can come from a real oil pressure problem, and an engine run without oil pressure can be ruined in minutes. If the red oil pressure light is on or the gauge reads low, pull over safely, shut the engine off and check the oil level before driving any further. If you can't confirm the engine has oil and real oil pressure, have it towed.

Common symptoms

Check engine light on (OBD-Codes.com)
Oil pressure warning light on (both sources)
Oil pressure gauge reading low or high (OBD-Codes.com)

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

Faulty engine oil pressure sensor or sender (both sources)
Wiring issue, such as excessive resistance or a short in the circuit between the sensor, the PCM and ground (both sources; OBD-Codes.com gives the detail)
Less often: PCM failure (both sources)
Low engine oil or an oil leak can cause low pressure and turn on the oil light, so OBD-Codes.com says to check the oil level first

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

Check the oil level on the dipstick with the engine off and on level ground. OBD-Codes.com points out that a leak, or an oil change where the oil wasn't refilled or the filter wasn't tightened, can leave the engine low on oil.
Look under the car and around the oil filter and drain plug for fresh oil leaks (OBD-Codes.com).
Look up technical service bulletins for your vehicle. OBD-Codes.com names Dodge-Chrysler-Ram-Jeep bulletin 18-034-14 as one known for this code.
Inspect the wiring and connector at the oil pressure sending unit for broken or frayed wires, burnt spots, loose pins, or oil inside the connector (OBD-Codes.com). A repair manual shows where the sender is on your engine.

Typical fixes

Top up or repair the cause of low oil if the level was low, then recheck (OBD-Codes.com)
Repair damaged wiring or a bad connector in the oil pressure sensor circuit (both sources)
Replace a faulty oil pressure sensor (RepairPal lists oil pressure sensor replacement as the common repair)
Replace or reprogram the PCM only as a last resort after proper diagnosis (OBD-Codes.com)

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

If the oil light stays on with a full oil level, a shop can confirm real oil pressure with a mechanical gauge before you trust the sensor reading
Checking the sensor terminals and harness for shorts to ground and out-of-spec resistance takes a digital multimeter and factory specs for your engine (OBD-Codes.com)
RepairPal cautions that most codes come from a sensor reporting an out-of-range value, so just replacing a part may not fix the underlying problem

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Is P0520 just a bad sensor?

Often it's the sensor or its wiring: OBD-Codes.com says the cause is most likely electrical, and both sources list the sensor and wiring first. But check the oil level before assuming that, because an engine that is actually low on oil can also turn on the oil pressure light.

Can I drive with P0520?

RepairPal rates it urgent. If the red oil pressure light is on or the gauge reads low, stop and check the oil before driving further. If you can't confirm the engine has oil and real oil pressure, have it towed rather than risk engine damage.

What's the difference between P0520 and P0524?

P0520 is a problem with the oil pressure sensor's circuit or signal. P0524 means the engine computer thinks the actual oil pressure is too low, which is usually more serious.

Sources

Last reviewed 2026-10-22. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.