What Does P0199 Mean?
This code indicates the engine oil temperature sensor circuit is producing an intermittent signal. The ECM has detected momentary spikes, dropouts, or erratic voltage changes from the sensor that do not correspond to actual oil temperature changes. This is typically caused by a poor electrical connection or failing sensor rather than a genuine temperature fluctuation.
Common Causes
35%
Loose or corroded engine oil temperature sensor connector making intermittent contact under engine vibration
30%
Intermittent break in the oil temperature sensor wiring at a flex point or where it contacts engine components
25%
Failing oil temperature sensor with an internally cracked thermistor producing erratic resistance changes
10%
ECM connector terminal corrosion or poor pin tension on the oil temp sensor input
Diagnostic Steps
1
Step 1: Monitor the oil temperature PID on a scan tool while the engine is running. Perform a wiggle test on the sensor connector and along the wiring harness, noting any sudden reading changes.
2
Step 2: Disconnect the sensor connector and inspect for corrosion, oil contamination, spread terminals, or damaged weatherpack seals. Clean and apply dielectric grease.
3
Step 3: With the sensor removed, measure thermistor resistance while gently tapping the sensor body. Erratic resistance changes confirm internal failure.
4
Step 4: Check wiring continuity from sensor to ECM while flexing the harness every 6 inches. Any resistance fluctuation indicates an intermittent open that needs repair.
5
Step 5: After correcting the issue, clear codes and monitor oil temperature data over at least three drive cycles to confirm stable readings.
Estimated Repair Cost
$60 - $220
Parts + labor, varies by vehicle and location
This code indicates the engine oil temperature sensor circuit is producing an intermittent signal. The ECM has detected momentary spikes, dropouts, or erratic voltage changes from the sensor that do not correspond to actual oil temperature changes. This is typically caused by a poor electrical conne...
The most common cause of P0199 (Engine Oil Temperature Sensor Intermittent) is: Loose or corroded engine oil temperature sensor connector making intermittent contact under engine vibration
Typical repair costs for P0199 range from $60 to $220, depending on the vehicle, location, and whether you do it yourself or go to a shop.
An intermittent oil temperature reading has minimal immediate safety impact but can compromise the ECM's ability to detect genuine oil overheating conditions, potentially masking a real problem.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0199 to identify the root cause.
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Quick Info
Category
Powertrain
System
Engine Lubrication/Management System
Difficulty
Type
Generic (SAE)
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