DTC P010600 – Engine Coolant Temperature (ECT) Sensor 1 Circuit Range/Performance.

✅ Meaning of P010600

The ECU detects that the coolant temperature signal is out of expected range, slow to change, or does not match engine condition.

This is not HIGH or LOW input — it’s range/performance, meaning the sensor is giving wrong or slow data.

✅ Common Symptoms

Hard cold start / long crank

Fan running at high speed always

Poor mileage

Rich or lean mixture

Overheating or false overheating indication

Temperature gauge fluctuating

🔧 Possible Causes

Sensor-related

1. Faulty ECT sensor (partial failure)

2. Sensor internal resistance not changing properly

Wiring / Connector Issues

3. Corroded connector pins

4. Water/oil contamination in connector

5. Open circuit in signal wire

6. High resistance in ground wire

7. Short-to-voltage or short-to-ground

Mechanical / Cooling System

8. Low coolant level

9. Air pocket in coolant system

10. Stuck thermostat (open/closed)

11. Engine not reaching operating temp

ECU Issues

12. Rare – ECU software or internal fault

🧰Step by step Diagnostic procedure

1. Check Coolant Level

Low coolant or air pockets cause incorrect sensor reading.

Top up and bleed air from system.

2. Scan Live Data

Check the ECT temperature reading:

Engine cold (morning):

ECT should be equal to ambient temperature (±3°C).

Engine running and warmed:

Normal temp: 85–95°C (varies by car).

If ECT shows:

-40°C → open circuit

140°C+ → short circuit

Slow response → sensor weak

3. Inspect Connector

Look for:

Green corrosion

Loose pins

Damaged plastic clip

Oil or coolant contamination

Clean connector → apply contact cleaner.

4. Wiring Test

Using multimeter:

Signal wire (with KOEO):

Should have 5V reference from ECU.

Ground wire:

Should be 0–0.1Ω resistance.

Check for:

Continuity

Short to ground

Short to 5V

5. ECT Sensor Resistance Test

Remove sensor and test:

Typical ECT resistance values (varies by model):

20°C → 2.5–3.5 kΩ

80°C → 250–350 Ω

If values do not match sensor is faulty.

6. Cooling System Check

Check thermostat operation (if stuck open → engine stays cool → performance fault).

Check radiator fan, leaks, blockages.

7. Reprogramming (If OEM Suggests)

Some vehicles need ECU update to correct false ECT readings.

🛠️ Most Common Fixes in Workshops

1. Replace ECT sensor

2. Clean connector & repair wiring

3. Fix coolant leaks and top up coolant

4. Replace thermostat

5. Bleed cooling system

Most cars get fixed with ECT sensor + connector cleaning.

Welcome To Madurai Car Service 💐🙏.