P2BBA code meaning
Engine Coolant Temperature Sensor 6 Circuit Intermittent/Erratic
Powertrain system Generic code P2Bxx codes Check engine light
What P2BBA means
P2BBA catches short dropouts or spikes in the sixth coolant sensor signal that never last long enough to count as a steady low or high fault. GM includes it in its 2019 L3B/common ECM tables (19OBDG03D) and in the 2025 edition (25OBDG03B): based on the last reading and the sensor time constant, the software allows only a limited change per sample, and if the signal leaps past that window for 5 s within 6 s the code is stored as Type B with the MIL on the second trip. The check pauses while P2BB8 or P2BB9 are active. GM bulletin 21-NA-149 lists P2BBA among the codes from chafed engine harnesses on 2019–2021 Silverado and Sierra 1500. Moving the harness during a live-data check usually reveals the spot; replacing the sensor alone rarely helps.
P2BBA at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2BBA
- MIL on after two trips, may go out again
- Sensor 6 value jumps in live data
- Other harness-related codes stored at the same time
Common causes of P2BBA
- Most likelyChafed engine harness with intermittent contact
- Most likelyLoose or corroded terminal at sensor 6 or the ECM
- Less likelySensor element with intermittent internal break
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Engine coolant temperature sensor 6Wiring harnessECM
What each part of P2BBA means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| B | Area: hybrid propulsion. |
| BA | The exact fault in that area. |
What to do next
- Note P2BBA and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2BBA
What does P2BBA mean?
P2BBA means "Engine Coolant Temperature Sensor 6 Circuit Intermittent/Erratic". P2BBA catches short dropouts or spikes in the sixth coolant sensor signal that never last long enough to count as a steady low or high fault. It is a generic code, so it means the same on every make.
Is it safe to drive with P2BBA?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2BBA fail an emissions test?
Yes, it can. P2BBA is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2BBA to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2BBA clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.