P2B2DEngine Coolant Temperature Sensor 5 Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- A low signal from coolant sensor 5 means its NTC resistance has collapsed, which the engine computer would read as an impossibly hot engine; a grounded signal wire or a shorted element is the usual reason. GM documents P2B2D in its configurable temperature input system: the sensor 5 channel fails when its resistance drops below 47.5 Ω in the 2019 L3B tables or 55 Ω in the 2025 ECM tables, a value tied to roughly 150 °C, for 5 s within a 6 s window; Type B, MIL on the second trip. GM bulletin 21-NA-149 lists P2B2D among the codes that chafed engine harnesses produce on 2019–2021 Silverado and Sierra 1500 trucks. NTN-SNR calls it signal too low for sensor 5. Fans may run at full speed until repair. P2B2E is the reverse fault.
- What you may notice
- MIL after two trips
- Radiator fans running constantly at high speed
- Other harness-related codes stored at the same time
- Likely causes
- LikelySignal wire grounded, for example by a chafed harness
- PossibleShorted sensor 5 element
- RareEngine control module input fault
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €30 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.