Engine Coolant Temperature Sensor, Checking: Notes
Observe all safety precautions: SAFETY PRECAUTIONS
View clean working conditions: CLEAN WORKING CONDITIONS
Prior to repair work, perform a preliminary check to verify the condition. Refer to PRELIMINARY CHECK .
Use only gold-plated terminals when servicing any component with gold-plated electrical harness connector terminals.
For wiring diagrams, component locations, and connector views, refer to the appropriate System Wiring Diagram.
Special tools and workshop equipment required
- Generic scan tool
- Multimeter
- Wiring diagram
Test requirements
- The Engine Control Module - J623- fuses OK.
- Battery voltage at least 12.5 volts.
- All electrical consumers such as, lights and rear window defroster, switched OFF.
- Vehicles with automatic transmission, shift selector lever into position "P" or "N".
- A/C switched OFF.
- Ground (GND) connections between engine/transmission/chassis OK.
- Ignition switched OFF.
- Engine cold.
Test procedure
Start diagnosis
-- Connect the scan tool.
-- Switch the ignition ON.
-- Using the scan tool, check the coolant temperature:
| Diagnostic text | Specified value |
|---|---|
| Coolant temperature | Approximate coolant temperature |
If the specified value was not obtained:
-- Continue test according to the following table:
| Indicated | Cause | Test |
|---|---|---|
| Approx. - 40.0° C | Open circuit or short circuit to Battery Voltage | ENGINE COOLANT TEMPERATURE SENSOR, CHECKING => Testing if scan tool display is approximately - 40.0° C |
| Approx. 140.0° C | Short circuit to Ground (GND) | ENGINE COOLANT TEMPERATURE SENSOR, CHECKING => Testing if scan tool display approximately 140.0° C |
If the specified value was obtained:
Checking internal resistance
-- Disconnect the Engine coolant temperature sensor -G62- electrical harness connector -1-.
-- Using a Multimeter, check the Engine coolant temperature sensor -G62- terminals 1 to 2 for resistance.
Use the chart below for the specified values:
Specified values:
| ECT Temperature vs Resistance | ||
| Temp (C) | min. value ohms | max. value ohms |
| - 40 | 36816 | 43714 |
| - 35 | 28840 | 33978 |
| - 25 | 17680 | 20530 |
| - 15 | 10940 | 12534 |
| - 5 | 6897 | 7804 |
| 0 | 5535 | 6226 |
| 5 | 4443 | 4970 |
| 15 | 2923 | 3235 |
| 25 | 1978 | 2167 |
| 35 | 1369 | 1486 |
| 45 | 965 | 1039 |
| 55 | 692 | 738 |
| 65 | 503 | 533 |
| 75 | 372 | 392 |
| 85 | 279 | 292 |
| 95 | 213 | 223 |
| 105 | 164 | 172 |
| 115 | 127 | 134 |
| 125 | 99 | 106 |
| 135 | 78 | 84 |
If any of the specified value's were not obtained:
-- Replace the Engine coolant temperature sensor -G62-. Refer to appropriate Service Information.
-- Go to Final procedures.
If the specified value was obtained:
-- Replace the Engine Control Module -J623 -. Refer to appropriate Service Information.
-- Go to Final procedures.