The engine oil temperature sensor B is an NTC thermistor fed with 5 V through a resistor: the hotter the oil, the lower the signal voltage. The engine module uses the oil temperature for variable cam timing (Ford disables it with cold oil or a sensor fault), engine protection and the oil life monitor; many engines have no such sensor and use a calculated oil temperature instead. Sensor B is a second oil temperature sensor whose position is defined by the manufacturer. P01BA is the plausibility fault of sensor B, the counterpart of P0196 – presumably a cold-start comparison, a warm-up check or a comparison with sensor A or a model, as GM documents for sensor A. No manufacturer document using the B-sensor codes was found, so it is unclear who fits a sensor B; the description follows sensor A and CARB's circuit monitoring requirement.
High severity. Can I keep driving?If the red oil warning light comes on, stop the car in a safe place and turn off the engine. Do not continue until you have confirmed the level and pressure.
Symptoms
- Check engine light on (depending on manufacturer)
- Implausible oil temperature values in scan data
- Usually no driving symptoms
Most likely causes
- Sensor B drifting or stuck
- Comparison sensor (oil sensor A, coolant) faulty
- Contact resistance in the connector
- Thermal management or oil cooler fault (genuine deviation)
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P01BA means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 1: Air and fuel
- BA: Specific fault in that system
Frequently asked questions
Can I keep driving with code P01BA?
If the red oil warning light comes on, stop the car in a safe place and turn off the engine. Do not continue until you have confirmed the level and pressure.
What causes code P01BA?
The most common causes are: sensor B drifting or stuck; comparison sensor (oil sensor A, coolant) faulty; contact resistance in the connector.
Related codes
- P01B9Engine Oil Temperature Sensor B Circuit
- P01BBEngine Oil Temperature Sensor B Circuit Low
- P01BCEngine Oil Temperature Sensor B Circuit High
- P0196Engine Oil Temperature Sensor A Range/Performance
- P0128Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.