Volvo All Engines (2004 Emissions) Fault Code: PID 110 FMI 4 Engine Coolant Temperature Sensor

Fault Condition: The Electronic Malfunction Lamp (EML) will turn on and Parameter Identification Code (PID) code P110 will set with Failure Mode Identifier (FMI) code 4 if the EMS Module senses that the ECT Sensor signal voltage is less than .17 volts. FMI code 5 will set if the ECT Sensor signal voltage is greater than 4.92 volts. If the EMS Module senses that the ECT Sensor signal is critically above range (219°F [104°C]), FMI code 0 will be set.

Possible repairs:

Turn the ignition key OFF first.

1) Disconnect the Engine Coolant Temperature (ECT) Sensor connector. Check for continuity between either pin of the ECT Sensor and a good ground. If continuity exists, replace the ECT Sensor.
2) Disconnect the Engine Coolant Temperature (ECT) Sensor connector. Disconnect connector B from the EMS Module. Connect a jumper between EMS Module harness connector B pins 18 and 27. Check for continuity between pins Black 3874 and Brown 3876 of the ECT Sensor harness connector. If there is NO continuity, there is an open ground circuit in the harness between the common ground splice to the ECT Sensor Sensor and the EMS Module. Locate and repair the open circuit.
3) Disconnect the Engine Coolant Temperature (ECT) Sensor connector. Measure the resistance across the pins of the ECT Sensor. If the resistance of the sensor is out of range or NOT within normal operating parameters (45313 to 71 ohms), replace the sensor.
4) Disconnect the Engine Coolant Temperature (ECT) Sensor connector. Disconnect connector B from the EMS Module. Measure the voltage between EMS Module connector B pin 18 and a good ground. If there is more than 0.5 volts present, there is a short circuit to voltage in the sensor return line. Locate and repair the short circuit to voltage.
5) If dirt, looseness, or deformed contacts are found, or the pin feels loose, repair EMS Module harness connector B.
6) Disconnect the ECT Sensor connector. Disconnect EMS Module connector B. Check for continuity between pin Brown 3876 of the ECT Sensor harness connector and EMS Module harness connector B pin 27.
If there is NO continuity, locate and repair the open signal circuit between the ECT Sensor harness connector and EMS Module harness connector B pin 27.
7) Disconnect the ECT Sensor connector. Disconnect EMS Module connectors A and B. Check for continuity between EMS Module harness connector B pin 27 and all other pins on EMS Module harness connectors A and B.
If continuity exists, the signal line is shorted to one of the other EMS Module circuits. Locate and repair the short circuit. If there is NO continuity, the signal line is shorted to ground somewhere else in the harness. Locate and repair the short circuit to ground.
8) Disconnect the ECT Sensor connector. Connect connector B to the EMS Module. Turn the ignition key ON. Measure the voltage at pin Brown 3876 of the ECT Sensor harness connector and a good ground.
If the measured voltage is between 4.5 and 5.5 volts, check the ECT Sensor harness connector for deformed pins or insufficient contact with the ECT Sensor pins.
9) Connect the ECT Sensor connector. Connect EMS Module harness connector B to the EMS Module. Turn the ignition key ON. If code P110 is still active, replace the EMS Module and retest the system.
If code P110 is NOT active, the procedures have corrected the problem. Check all connectors to ensure proper connections.
10) Connect the ECT Sensor connector. Connect connector B to the EMS Module. Turn the ignition key ON. If code P110 is still active, check the EMS Module and connectors A and B for dirt, loose or shorted pins, or any other
repairable damage. If no problems are evident, or are NOT repairable, replace the EMS Module and retest the system.
11) Disconnect the ECT Sensor connector. Disconnect EMS Module connector B. Check for continuity between EMS Module harness connector B pin 27 and all other pins on EMS Module connector B. If continuity exists, the signal line is shorted to one of the other EMS Module circuits. Locate and repair the short circuit to voltage, then replace the sensor. If there is NO continuity, the signal line is shorted to voltage somewhere else in the harness. Locate and repair the short circuit to voltage.