Fix P0199: STEP-BY-STEP diagnostic GUIDE!

The P0199: Engine Oil Temperature Sensor Intermittent indicates an intermittent issue in the engine oil temperature sensor circuit. This problem can arise due to various causes, such as a faulty sensor, intermittent wiring connections, or even a malfunctioning Powertrain Control Module (PCM). When this code is triggered, it suggests that the system responsible for monitoring the engine oil temperature is experiencing intermittent disruptions, which could potentially impact engine performance.

P0199 – Quick Overview

Meaning	P0199: Engine Oil Temperature Sensor Intermittent
Is it serious?	This code can be serious as it may affect the engine’s ability to monitor and maintain the correct oil temperature, leading to potential engine damage if left unresolved.
Possible causes	– Intermittent connection in the engine oil temperature sensor circuit – Faulty engine oil temperature sensor – Wiring or connector issues – Faulty PCM
How to diagnose?	– Inspect the engine oil temperature sensor for intermittent operation. – Check wiring and connectors for loose or corroded contacts. – Perform a wiggle test to identify intermittent faults. – Replace or repair any faulty components.

P0199 Meaning

The P0199: Engine Oil Temperature Sensor Intermittent means there’s an issue with the system that monitors your engine’s oil temperature. This issue is intermittent, which means it might come and go, making it harder to diagnose. It could be caused by a loose connection, a faulty sensor, or a problem with the computer that manages the engine. When this code appears, it indicates that the engine might not be accurately monitoring the oil temperature, which could affect how well the engine runs and its overall longevity.

Step-by-step diagnostic guide

Follow the outlined procedure to diagnose this DTC by eliminating possible causes one by one.

Action	Description	Tools Needed
Check for Other Codes	Use an OBD-II scanner to check if there are any other related codes present. These might give additional clues about the problem.	OBD-II Scanner
Inspect the Engine Oil Temperature Sensor	Visually inspect the engine oil temperature sensor for any signs of damage, intermittent operation, or loose connections. Ensure it is securely attached.	Flashlight, Safety Gloves
Test the Engine Oil Temperature Sensor	Using a multimeter, test the sensor for proper resistance and operation. Compare the readings to the manufacturer’s specifications.	Multimeter, Manufacturer’s Specifications
Inspect Wiring and Connectors	Carefully check the wiring and connectors leading to the engine oil temperature sensor for any signs of wear, corrosion, or breaks. Look for loose wires.	Flashlight, Multimeter
Perform a Wiggle Test	While the engine is running, gently wiggle the wiring harnesses to see if the problem can be induced. This can help identify intermittent faults.	Hands, Safety Gloves
Repair or Replace Damaged Wiring/Connectors	If any wiring or connectors are damaged or corroded, repair or replace them. Ensure connections are secure and free from dirt or corrosion.	Wire Strippers, Electrical Tape, Replacement Wires/Connectors
Check the PCM (Powertrain Control Module)	Inspect the PCM and its connections for any signs of damage or loose connections. If the PCM is suspected to be faulty, it may need reprogramming or replacement.	OBD-II Scanner, Multimeter
Clear the Code and Test Drive	After completing the necessary repairs, clear the P0199 code using the OBD-II scanner. Take the vehicle for a test drive to ensure the issue is resolved.	OBD-II Scanner, Vehicle Owner’s Manual
Recheck for Codes	After the test drive, re-scan the vehicle to ensure the P0199 code has not reappeared. If the code returns, further diagnosis may be required.	OBD-II Scanner