P0199 code definition
P0199 is indicating a fault in the engine oil temperature sensor circuit. This code is similar to P0195, P0196, P0197, P0198.
What the P0199 code means
P0199 is found when the ECM has detected an intermittent fault in the engine oil temperature sensor. The ECM expects to see a voltage signal coming from the oil temperature sensor. When the signal is intermittently out-of-range, P0199 is set.
This condition causes a failsafe mode to be triggered and a diagnostic trouble code (DTC) set to prevent damage to the vehicle. Failsafe mode will remain in effect until the fault is resolved or normal sensor operation is detected.
What causes the P0199 code?
- Faulty oil temperature sensor
- Open or short in wiring harness
- Electrical connection that is faulty or loose
What are the symptoms of the P0199 code?
The most common symptom is the ECM after the fault is detected will set a failsafe mode and cause the Check Engine Light to be illuminated on the dash. No drivability issues are normally associated with P0199.
How does a mechanic diagnose the P0199 code?
A technician will begin by installing an OBD-II scan tool into the vehicle's DLC port. They will then check for any code present and the freeze frame data associated with each code.
Next, the technician will perform a road test. Under the road test the technician will do their best to drive under the same conditions as the code was set under.
Once the code reappears, a visual inspection of the wiring and sensor itself will be performed to look for anything damaged, broken, or abnormal.
If there is nothing found during the visual inspection, a test will be performed on the engine oil temperature sensor using the scan tool. This scan tool will monitor changes in voltage and readings over time and will allow the technician to recognize any underlying issues.
Common mistakes when diagnosing the P0199 code
Not following steps in the proper order or skipping steps is the most common mistake made when diagnosing this code.
How serious is the P0199 code?
The most serious side effect of P0199 is the oil temperature sensor not working. The temperature sensor is needed to prevent engine damage in case of the vehicle overheating and is a critical component in normal vehicle operation. The only symptom that is noticed in most cases is the Check Engine Light illuminated on the dashboard.
What repairs can fix the P0199 code?
- Replacement of engine oil temperature sensor
- Repairing or replacing a bad sensor wiring harness
- Repairing poor electrical connections
Additional comments for consideration regarding the P0199 code
P0199 is a generic code that is commonly seen - especially on higher mileage or older vehicles.
With P0199 being an intermittent issue, it can be difficult to track down at times. An advanced level scan tool is required to diagnose this code. These advanced scanners are able to track and graph changes in sensor data that are especially useful in circumstances where intermittent issues are present.
Need help with a P0199 code?
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