Body
Generic/SAE
OBD-II Fault Code
B2211: Low Coolant Lamp Output Circuit Short to Battery
Meaning, symptoms, likely causes, diagnostic checks and repair guidance for B2211.
Cooling system
Use this category to narrow your checks before replacing parts.
High
Severity is a general guide. Confirm with scan-tool data and vehicle symptoms.
What B2211 usually means
Low Coolant Lamp Output Circuit Short to Battery.
Common symptoms
Body/accessory warning lamp or feature not working; Temperature gauge abnormal; Overheating or slow warm-up possible
Likely causes
Low coolant; Faulty thermostat; Coolant temperature sensor/wiring fault; Cooling fan issue; Wire shorted to power feed; Incorrectly repaired harness; Internal component short; Low signal voltage; Weak power supply; High resistance/poor ground; Failed sensor
Diagnostic checks
Check related fuses, connectors, grounds and switch/module power supply; Check coolant level only when engine is cool; Compare scan-tool temperature to actual temperature; Check for unwanted voltage on signal/control circuit; Check sensor reference voltage, ground and signal voltage
Repair guidance
Repair leaks, replace thermostat/sensor/fan component after confirming fault; Repair harness short to power or replace internally shorted component; Repair poor ground/power feed or replace confirmed faulty sensor
Verification after repair
Operate the affected body/accessory system and rescan