Diagnostics and testing 4.4L (Discovery 3)

Inspection and verification

1. Ensure that the customer's complaint is justified.

2. Visually inspect for obvious mechanical and electrical problems.

Mechanical factors	Electrical factors
Coolant leaks Coolant hoses Coolant expansion tank Radiator Heater radiator Auxiliary drive belt Fan with viscous coupling	Fuses and fuses Wiring harness Loosening or corrosion of connector(s) Coolant Temperature (ECT) Sensor

3. If an obvious cause for the problem you identified or the customer described is found, resolve it before moving on to further action. (if possible).

4. Use the approved diagnostic system or scan tool to retrieve all diagnostic trouble codes (DTCs) before referring to the symptom chart or DTC index.

Clear all DTCs after troubleshooting.

Table of signs of malfunction

Sign of malfunction	Possible reason	Actions
Loss of coolant	Hoses Hose connections Radiator Coolant pump Heater radiator Gaskets Cracks in engine castings Cylinder Block Rod Plugs	Perform a visual inspection. If there are no obvious leaks, perform a pressure test using service station equipment. Repair if necessary. Refer to the appropriate section in the service station manual.
Overheat	Low coolant level/contaminated Thermostat Fan with viscous coupling ECT sensor Obstructions to air flow through the radiator	Check the coolant level and condition. Check the thermostat and make any necessary repairs. Perform a pressure test of the cooling system. Check the operation of the viscous fan, make sure that the viscous fan rotates freely. Check for obstructions to air flow through the radiator. Repair if necessary. Refer to the relevant section in the service station manual.
The engine does not reach normal temperature	Thermostat Fan with viscous coupling	Check the operation of the thermostat. Check the operation of the fan with viscous coupling, make sure that the fan with viscous coupling does not stick.

Details can be found on the website: LRMAN.RU

DTC Index

DTC codes	Description	Possible reasons	Actions
P011623	Engine Coolant Temperature Sensor 1 Circuit Range/Performance Problem	Low coolant level Engine thermostat malfunction ECT Sensor Signal Circuit - Intermittent High Resistance ECT sensor failure	Check the coolant level and thermostat operation. (stuck open). Refer to the appropriate section in the workshop manual. Refer to the guided diagnostic routine for this code on the approved diagnostic system.
P011624	Engine Coolant Temperature Sensor 1 Circuit Range/Performance Problem	Low coolant level Engine coolant thermostat malfunction ECT Sensor Signal Circuit - Intermittent High Resistance ECT sensor failure	Check the coolant level and thermostat operation. (stuck open). Refer to the appropriate section in the workshop manual. Refer to the guided diagnostic routine for this code on the approved diagnostic system.
P011629	Engine Coolant Temperature Sensor 1 Circuit Range/Performance Problem	Low coolant level Engine coolant thermostat malfunction ECT Sensor Signal Circuit - Intermittent High Resistance ECT sensor failure	Check the coolant level and thermostat operation. (stuck open). Refer to the appropriate section in the workshop manual. Refer to the guided diagnostic routine for this code on the approved diagnostic system.
P011700	Engine Coolant Temperature (ECT) Sensor 1 Circuit Low Voltage	ECT sensor disconnected ECT Sensor Signal Circuit High Resistance, Short to Battery Positive ECT sensor failure	Refer to the guided diagnostic program for this code on the approved diagnostic system.
P011800	Engine Coolant Temperature (ECT) Sensor 1 Circuit High Voltage	Engine overheating condition/cooling fan malfunction ECT Sensor Wiring: Short to Ground ECT sensor failure	Check the coolant level and thermostat operation. (stuck in closed position). Check for cooling fan DTCs. Refer to the guided diagnostic routine for this code on the approved diagnostic system.