P0520 on Cadillac: How to Diagnose & Fix
Engine Oil Pressure Sensor/Switch Circuit Malfunction
2 Cadillac models · 2 documented issues · 2 critical
P0520 on Cadillac by model: symptoms, diagnosis and fix
After widespread engine failures and an NHTSA investigation, GM recalled all 2021-2024 vehicles equipped with the 6.2L V8 engine including the CT5-V. The recall addresses potential connecting rod bearing failure that can cause engine seizure, stalling, or fire risk. The recall covers both naturally aspirated L87 and supercharged LT4 variants.
Common Symptoms
- Knocking or ticking noise from engine
- Check engine light illuminated
- Oil pressure warning light
- Engine stalling while driving
- Reduced engine power message
How to Fix
Contact Cadillac dealer immediately to check recall eligibility. GM will inspect and replace engine components as needed at no cost. Do not ignore any knocking sounds or oil pressure warnings. The recall remedy includes enhanced engine monitoring software and replacement of affected components.
Sources for this issue (1)
The T1XX Escalade's 6.2L L87 V8 has a documented connecting-rod bearing failure that is separate from the older AFM lifter problem and separate from oil consumption. Manufacturing debris left in the crankshaft oil passages and rod-bearing dimensional variation on engines built in a specific window let the bearings wear through the overlay and into the copper, which then knocks and can seize the engine outright. The failure is often abrupt: owners report a knock, an oil pressure warning, or a complete no-start seizure with very little warning and sometimes under 30,000 miles. The complaint concentration is striking - CarComplaints shows 34 of the 61 total complaints on the 2023 Escalade filed under engine problems, and the 2021 Escalade carries engine as its largest NHTSA complaint category with multiple open defect investigations and recalls. GM has addressed affected VINs through a field action that both inspects/replaces engines and, for engines passing inspection, changes the required oil viscosity and shortens the service interval.
Common Symptoms
- Deep knocking or rod knock from the lower engine that changes with throttle
- Low oil pressure warning or the check engine light before failure
- Engine seizes and will not crank, sometimes with no prior noise
- Metal flake or copper-colored debris on the oil filter or drain plug
- Loss of power or a sudden stall while driving
How to Fix
First, run your VIN through the GM/Cadillac owner recall lookup and the NHTSA VIN recall tool - the remedy for an affected vehicle is dealer-performed and free, and it is the only path to a covered engine replacement. If the engine is symptomatic, stop driving it; continuing to run a knocking rod bearing turns a bearing job into a crankshaft and block replacement. Do not let a shop tell you a rod knock is a lifter - the two sound different and are diagnosed differently: a rod knock is a deep, load-dependent thump that changes with throttle and often quiets briefly on a cylinder-cut test, whereas an AFM lifter tick is a lighter top-end tap present at idle. Have the dealer perform the prescribed bearing inspection and pull an oil sample for analysis; copper and lead in the oil report is direct evidence. For engines that pass inspection, GM's remedy specifies a heavier oil viscosity and a shorter change interval than the original spec - follow it exactly, because the whole point is raising the oil film thickness at the bearing. Out of pocket, an L87 replacement is roughly $8,000-$12,000, which makes pursuing the field action the only sensible route.
Sources for this issue (2)
P0520 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0520 mean on a Cadillac?
P0520 stands for "Engine Oil Pressure Sensor/Switch Circuit Malfunction." This code indicates a general electrical fault in the circuit for the engine oil pressure sensor or switch. The computer monitors this circuit to know your oil pressure, and it has detected a signal that is missing, shorted, or otherwise out of the expected electrical range. This is typically a wiring or sensor problem rather than an actual loss of oil pressure, but because oil pressure is critical to engine life, it should never be ignored until confirmed. If oil pressure truly is low, serious engine damage can result. On Cadillac it is documented across 2 models: CT5, Escalade.
What are the most common causes of P0520?
The most common causes of P0520 are: Faulty oil pressure sensor or switch, Damaged, corroded, or loose wiring/connector at the sensor, Open or short in the sensor circuit wiring, Poor ground connection, Low engine oil level or genuinely low oil pressure, Failed PCM/ECM (less common). The specific cause varies by vehicle.
How much does it cost to fix P0520 on a Cadillac?
Repair costs vary widely with the root cause and Cadillac model; each issue on this page carries its own estimate where one is published.
Looking for P0520 on a different make?
View P0520 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.