B2381
Low Severity (Level 2)Heater Coolant Temp sensor circuit Open
B2381 usually means heater Coolant Temp sensor circuit Open.
Can you still drive with B2381?
⚠️Short-distance driving is usually OK, but have this diagnosed within a week to prevent further damage.
Typical repair cost: $40 – $300
Severity Level 2 — Low
This code indicates a minor issue that is unlikely to cause immediate driveability problems. You can typically continue driving but should have the vehicle inspected at your earliest convenience.
Common Symptoms
- Temperature gauge not working — no response when activated
- Temperature gauge working intermittently, then stopping completely
- Infinite resistance in the engine coolant temperature sensor circuit — broken wire or disconnected connector
- Fault may be intermittent — code may clear itself and reappear
- Reduced vehicle functionality related to the engine coolant temperature sensor
Possible Causes
- Broken wire or connector pin in the engine coolant temperature sensor harness — common at flex points like door jambs or where wiring moves
- Disconnected or loose electrical connector — may have been bumped during other repairs
- Failed coolant temperature sensor — internal open circuit from age, heat cycling, or vibration
- Corrosion completely severing a wire or connector terminal — green crust on copper wiring
- Wiring harness damage from rodent chewing — look for nesting material near the engine or under dash
Common Fixes
- Scan vehicle with a professional-grade OBD2 scanner to read all stored codes and freeze frame data — note the conditions when the code set ($36-109 at shop, free at auto parts store for basic scan)
- Visually inspect the engine coolant temperature sensor wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $75 diagnostic fee at shop)
- Trace the engine coolant temperature sensor wiring from connector to connector with a multimeter set to continuity/resistance mode — find and repair the break in the circuit ($140-295 labor for diagnosis and repair)
- Check and reseat all connectors in the engine coolant temperature sensor circuit — disconnect, inspect pins, clean with electrical contact cleaner, apply dielectric grease, and reconnect firmly ($13 DIY or $95 shop minimum)
- If coolant temperature sensor has failed internally (open circuit inside), replace it — don't try to repair sealed components ($40-250)
Estimated Repair Cost
These are estimated costs based on generic repair data. Actual costs may vary depending on your vehicle, location, and labor rates.
Frequently Asked Questions
What does B2381 mean?
B2381 stands for "Heater Coolant Temp sensor circuit Open". B2381 usually means heater Coolant Temp sensor circuit Open.
Can you drive with B2381?
Short-distance driving is usually OK, but have this diagnosed within a week to prevent further damage.
How much does it cost to fix B2381?
Repair costs for B2381 typically range from $40 to $300, depending on your vehicle make, model, and local labor rates. Common fixes include: Scan vehicle with a professional-grade OBD2 scanner to read all stored codes and freeze frame data — note the conditions when the code set ($36-109 at shop, free at auto parts store for basic scan); Visually inspect the engine coolant temperature sensor wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $75 diagnostic fee at shop); Trace the engine coolant temperature sensor wiring from connector to connector with a multimeter set to continuity/resistance mode — find and repair the break in the circuit ($140-295 labor for diagnosis and repair).
Will B2381 clear itself?
Related Repair Costs
Explore Repair Costs
Related OBD-II Codes
These codes are in the same range as B2381 and often share similar causes and fixes.
Worried about repair costs?
Get transparent estimates and verify your mechanic's quote before authorizing repairs.
Related Discussions
See what other car owners are saying about this code and related repairs.
View B2381 discussions in the community