Checking The Wiring And Component
Check the resistance of the engine coolant temperature (ECT) sensor.
The engine coolant temperature (ECT) sensor may be defective as a result of the signal cable having been short-circuited to supply voltage. Check this before replacing the sensor.
Check the signal cable between control module terminal #A4 (#A4) and engine coolant temperature (ECT) sensor terminal #1. Check for an open-circuit. Check for a short-circuit to supply voltage.
HINT: With the ignition on and engine coolant temperature (ECT) sensor connector disconnected the voltage between terminal #1 and ground terminal must be approximately 5 V.
Check the ground lead between control module terminal #A60 (#A60) and engine coolant temperature (ECT) sensor terminal #2. Check for an open-circuit.
Remedy as necessary.
Other information
- To connect the breakout box / access the control module, see CONNECTING THE BREAKOUT BOX
- For B5xx4T, see REPLACING THE THERMOSTAT AND/OR ENGINE COOLANT TEMPERATURE SENSOR
- For B6xx4T, see ENGINE COOLANT TEMPERATURE (ECT) SENSOR, REPLACING .
- For resistance values, see COMPONENT SPECIFICATIONS
- For 6 cylinder engines -2004, see SIGNAL SPECIFICATION
- For 6 cylinder engines 2005-, see SIGNAL SPECIFICATION .
- see CHECKING WIRING AND TERMINALS .
- Continue
Refer to VERIFICATION