The Engine Coolant Temperature (CTS/ECT) Sensor uses electrical resistance to measure the temperature of the coolant/antifreeze mixture. The ECU uses this data to keep engine temperature in the ideal range—controlling cooling fan operation, EGR function, and fuel mixture enrichment as needed.
How It Works:
- Measures coolant temperature via a temperature-sensitive resistor.
- Sends a changing voltage/signal to the ECU as temperature rises/falls.
- The ECU adjusts cooling fan, EGR, and fuel mixture to maintain proper engine temperature and driveability.
Product Features & Benefits from Walker Products:
- Exact OE Fit: Direct replacement for quick, hassle-free installation.
- OE Replacement Quality: Built to meet or exceed OE performance specifications.
- Durable Construction: Designed to resist heat, vibration, and corrosion at the connector/terminal.
- Restores Performance & Efficiency: Provides accurate temperature data for proper fan control, fueling, and emissions.
- Aftermarket Expertise: Backed by over 75 years supplying reliable engine management components.
Symptoms of a Failing CTS/ECT:
- Reduced fuel efficiency
- Poor start
- Black smoke from the exhaust
- Overheating engine
- Poor idle (needing to press the gas pedal to keep running)
- Check Engine Light on
Common Check Engine Light (CEL) / OBD-II Codes
In 1996 the EPA required OBD-II on all passenger vehicles, standardizing emissions and fault diagnostics across manufacturers (later expanded to heavy-duty applications).
The codes below are common for this product type. Always consult a professional mechanic and follow vehicle manufacturer and EPA guidelines for diagnosis, replacement, code clearing, and ECU/PCM relearn procedures. Walker Products will not be responsible for use of this information.
- P008F – Engine Coolant Temperature/Fuel Temperature Correlation
- P00B1 – Radiator Coolant Temperature Sensor Circuit
- P00B2 – Radiator Coolant Temperature Sensor Circuit Range/Performance
- P00B3 – Radiator Coolant Temperature Sensor Circuit Low
- P00B4 – Radiator Coolant Temperature Sensor Circuit High
- P00B5 – Radiator Coolant Temperature Sensor Circuit Intermittent/Erratic
- P00B6 – Radiator Coolant Temperature/Engine Coolant Temperature
- P0115 – Engine Coolant Temperature Sensor 1 Circuit
- P0116 – Engine Coolant Temperature Sensor 1 Circuit Range/Performance
- P0117 – Engine Coolant Temperature Sensor 1 Circuit Low
- P0118 – Engine Coolant Temperature Sensor 1 Circuit High
- P0119 – Engine Coolant Temperature Sensor 1 Circuit Intermittent
- P011A – Engine Coolant Temperature Sensor 1/2 Correlation
- P011B – Engine Coolant Temperature/Intake Air Temperature Correlation
- P0125 – Insufficient Coolant Temperature for Closed Loop Fuel Control
- P0126 – Insufficient Coolant Temperature for Stable Operation
- P0128 – Coolant Thermostat (Coolant Temperature Below Thermostat …)
- P050C – Cold Start Engine Coolant Temperature Performance
- P060F – Internal Control Module Coolant Temperature Performance
- P063F – Auto Configuration Engine Coolant Temperature Input not Present
- P0A00 – Motor Electronics Coolant Temperature Sensor Circuit
- P0A02 – Motor Electronics Coolant Temperature Sensor Circuit Low
- P0A03 – Motor Electronics Coolant Temperature Sensor Circuit High
- P0A04 – Motor Electronics Coolant Temperature Sensor Circuit Intermittent
- P0C42 – Hybrid Battery Pack Coolant Temperature Sensor Circuit
- P0C43 – Hybrid Battery Pack Coolant Temperature Sensor Circuit
- P0C44 – Hybrid Battery Pack Coolant Temperature Sensor Circuit Low
- P0C45 – Hybrid Battery Pack Coolant Temperature Sensor Circuit High
- P0C46 – Hybrid Battery Pack Coolant Temperature Sensor Circuit
- P2182 – Engine Coolant Temperature Sensor 2 Circuit
- P2183 – Engine Coolant Temperature Sensor 2 Circuit Range/Performance
- P2184 – Engine Coolant Temperature Sensor 2 Circuit Low
- P2185 – Engine Coolant Temperature Sensor 2 Circuit High
- P2186 – Engine Coolant Temperature Sensor 2 Circuit Intermittent/Erratic
- U0116 – Lost Communication With Coolant Temperature Control Module
- U0456 – Invalid Data Received From Coolant Temperature Control Module