Engine Coolant Temperature Sensor - G62-, CHECKING
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 applicable 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 | Approx. coolant temperature |
If the specified value is not obtained:
-- Continue test according to the following table:
| Indicated | Cause | Test |
|---|---|---|
| approx. - 40.0° C | Open circuit or short circuit to (B+) | Refer to Testing if display is approx. - 40.0° C (See Fig 2) |
| approx. 140.0° C | Short circuit to Ground (GND) | Refer to Testing if display approx. 140.0° C (See Fig 3) |
If the specified value was obtained:
-- Start the engine and let it run at idle.
The temperature value must increase uniformly in increments of 1.0° C.
If the engine shows problems in certain temperature ranges and if the temperature does not climb uniformly, the temperature signal is intermittent.
-- Replace the Engine Coolant Temperature Sensor - G62-. Refer to the appropriate service information
Checking internal resistance
-- Disconnect the Engine Coolant Temperature Sensor -G62- electrical harness connector -arrow-.
-- 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 values was not obtained:
-- Replace the Engine Coolant Temperature Sensor - G62-. Refer to appropriate service information.
Testing If Display Is Approx. - 40.0° C
-- Disconnect the Engine Coolant Temperature Sensor -G62- electrical harness connector -arrow-.
-- Using a jumper wire, connect the Engine Coolant Temperature Sensor -G62- electrical harness connector terminals 1 to 2.
-- Check the value indicated on the scan tool display.
If the value jumps to approx. 140.0° C
-- End diagnosis and switch the ignition off.
-- Replace the Engine Coolant Temperature Sensor - G62-. Refer to appropriate service information.
If indication remains at approx. -40.0° C:
Testing If Display Approx. 140.0° C
-- Disconnect the Engine Coolant Temperature Sensor -G62- electrical harness connector -arrow-.
If indication jumps to approx. -40.0° C:
-- End diagnosis and switch ignition off.
-- Replace theEngine Coolant Temperature Sensor - G62-. Refer to appropriate service information.
If indication remains at approx. 140.0° C:
Checking wiring
-- Remove the Engine Control Module -J623-. Refer to appropriate service information.
-- Using a multimeter, check the Engine Coolant Temperature Sensor - G62- electrical harness connector terminals to the Engine Control Module -J623- electrical harness connector T105 terminals for an open circuit according to the wiring diagram.
| Engine Coolant Temperature Sensor - G62- electrical harness connector terminals | Engine Control Module -J623- electrical connector T105 terminals |
|---|---|
| 1 | 30 |
| 2 | 8 |
Specified value: 1.5 Ω Max.
If the specified value was not obtained:
-- Check the wiring for a short circuit to Battery (+), or an open circuit.
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the faulty wiring connection.
If no malfunction is detected in the wiring:
-- Replace the Engine Control Module -J623-. Refer to appropriate service information.
Final Procedures
After the repair work, the following work steps must be performed in the following sequence:
- Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
- If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
- If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .