TH. MFI #13 Engine Coolant Temp. (ECT) Sensor Signal Absent

TH. MFI#13

MFI#13 Engine coolant temperature (ECT) sensor signal absent




Fault message conditions:
The fault message is logged if voltage is above 4.5 V.

Causes of fault:
Break in the wiring between MFI#13 and the ECT sensor.
Break in the ECT sensor.

Fault symptoms:
Engine difficult to start when warm.

Note: When checking wiring the ST should be disconnected In accordance with QA2. QA. Connecting The Volvo Scan Tool (ST)

TH1




Monitor Test
- Warm up the engine.
- Check the engine temperature in Monitor Test.
When the engine is warm temperature should be approx. 90°C (194°F).

If the temperature Is OK:
Intermittent fault.
^ Check the connections for loose contacts in accordance with NA5. NA. Checking the Wiring

If the temperature is under 0°C (32°F):
^ Check the sensor resistance TH2.

If the temperature is wrong in other ways:
^ Check the connections for contact resistance in accordance with NA6. NA. Checking the Wiring

TH2




Checking the sensor resistance
- Ignition off.
Connect an ohmmeter between terminal 1 on the ECT sensor and GND.




The ohmmeter reading should agree with the graph.

If this value is OK:
^ Check the wiring between MFI#13 and the sensor for breaks in accordance with NA2. NA. Checking the Wiring

If the reading is incorrect:
^ Try using a new ECT sensor.