Engine Oil Temperature Sensor Intermittent
The P0199 code indicates that the Engine Control Module (ECM) has detected an intermittent signal from the Engine Oil Temperature (EOT) sensor. This sensor monitors oil temperature to optimize engine performance and protect against overheating. An intermittent fault may be caused by a loose connection, damaged wiring, or a failing sensor, leading to erratic readings that can affect fuel delivery and ignition timing.
01. Most Common Causes
- Faulty engine oil temperature sensor
- Damaged or corroded wiring/connectors
- Intermittent short or open circuit in sensor circuit
- Poor electrical connection at sensor or ECM
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine performance issues (rough idle, hesitation)
- Poor fuel economy
- Possible overheating or inaccurate temperature gauge
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data to capture conditions when fault occurred.
Step 2: Visually inspect the EOT sensor and its wiring for damage, corrosion, or loose connections.
Step 3: Use a multimeter to test sensor resistance at various temperatures and compare to specifications.
Step 4: Check for intermittent shorts or opens by wiggling the wiring harness while monitoring sensor signal with a scan tool.
Step 5: If sensor and wiring are OK, test the ECM's ability to read the sensor signal; replace sensor if faulty.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances with this code, as inaccurate oil temperature readings can lead to engine damage from overheating or improper lubrication. Have it diagnosed promptly.
How much does it cost to fix?▼
The typical repair cost ranges from $50 to $150, including parts (sensor) and labor. Diagnostic fees may add $50-$100.