U0116 — Lost Communication With Coolant Temperature Control Module
vehicle network
Is it safe to drive?
Drive with caution Drive with caution and watch the temperature gauge. A thermostat stuck open mainly costs fuel; any sign of overheating means stop immediately — driving an overheating engine destroys head gaskets and worse.
How to diagnose with an OBD scanner
- Read the code and freeze frame Connect an OBD2 scanner, confirm U0116 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
- Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many U0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
- Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the engine cooling and temperature control for damage, corrosion, chafing or poor contact.
- Subsystem check Watch coolant temperature in live data during warmup — it should climb smoothly to operating temperature.
- Subsystem check Check coolant level and feel upper/lower radiator hoses to verify thermostat operation.
- Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm U0116 does not return.
Approximate repair cost
Repair cost depends on which component actually failed. Typical scenarios for U0116 (parts and labor, USD, independent shop rates): Replace the coolant temperature sensor: $100–$300; Cooling system repair (pump, fan, radiator): $300–$1,200; Replace the thermostat: $150–$400. Overall, fixing U0116 usually costs between $100 and $1,200. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.
Common questions
How do I diagnose U0116 myself?
Start with a scan: confirm U0116, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the engine cooling and temperature control, and verify the suspect component against live data before buying parts.
What does OBD2 code U0116 mean?
Lost Communication With Coolant Temperature Control Module (U0116): a vehicle network fault affecting the engine cooling and temperature control. Short, gentle driving to a shop is usually possible. Most often caused by faulty coolant temperature sensor, wiring faults in the sensor circuit, thermostat stuck open or closed.
How much does it cost to fix U0116?
Replace the coolant temperature sensor — $100–$300; Cooling system repair (pump, fan, radiator) — $300–$1,200; Replace the thermostat — $150–$400. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.
What is the most common cause of U0116?
The most common causes are: faulty coolant temperature sensor, wiring faults in the sensor circuit, thermostat stuck open or closed.
What are the symptoms of U0116?
Drivers most often notice: temperature gauge reads low or never reaches normal, Check Engine Light on, cooling fans running constantly, increased fuel consumption.
What does U0116 mean?
U0116 (Lost Communication With Coolant Temperature Control Module) is stored when self-diagnostics detect abnormal readings or behaviour of the engine cooling and temperature control. It belongs to the vehicle network category.
The module monitors this system continuously while driving. When readings fall outside the expected range for a defined number of drive cycles, it stores U0116 and switches on the warning light. Freeze frame data saved with the code shows the exact conditions — rpm, load, temperature, speed — at the moment the fault was detected, which is the best starting point for diagnosis.
What causes U0116?
- faulty coolant temperature sensor
- water pump or radiator issues
- low coolant level or air in the system
- failed cooling fan or fan relay
Common symptoms of U0116
- temperature gauge reads low or never reaches normal
- Check Engine Light on
- cooling fans running constantly
- increased fuel consumption
- poor cabin heat
How to diagnose U0116
- Connect an OBD2 scanner, confirm U0116 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
- Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many U0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
- Visually inspect the wiring harness and connectors related to the engine cooling and temperature control for damage, corrosion, chafing or poor contact.
- Watch coolant temperature in live data during warmup — it should climb smoothly to operating temperature.
- Check coolant level and feel upper/lower radiator hoses to verify thermostat operation.
- Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm U0116 does not return.
How to fix U0116
Start with the cheapest and most common causes before replacing expensive parts:
- Replace the coolant temperature sensor — $100–$300
- Cooling system repair (pump, fan, radiator) — $300–$1,200
- Replace the thermostat — $150–$400
How much does it cost to fix U0116?
Repair cost depends on which component actually failed. Typical scenarios for U0116 (parts and labor, USD, independent shop rates):
- Replace the coolant temperature sensor: $100–$300
- Cooling system repair (pump, fan, radiator): $300–$1,200
- Replace the thermostat: $150–$400
Overall, fixing U0116 usually costs between $100 and $1,200. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.
Can you drive with U0116?
Drive with caution and watch the temperature gauge. A thermostat stuck open mainly costs fuel; any sign of overheating means stop immediately — driving an overheating engine destroys head gaskets and worse.