Diagnosis and check 4.4L (Discovery 3)

Inspection and verification

1. Check the validity of the customer's complaint. Be aware that the vehicle has a number of systems that communicate with the message center to provide the driver with information useful in diagnosing problems.

2. Visually inspect for obvious signs of mechanical and electrical damage.

Mechanical factors	Electrical Factors
Fuel filler cap and seal Fuel filler neck Fresh air filter DMTL (clogging, etc.) Fuel tank (leaks, damage, etc.) Fuel lines and connections, etc. Adsorber Purge valve DMTL pump module	Fuses Electrical connectors tourniquet (s) electrical wiring Purge valve DMTL pump

3. If an obvious cause of a problem you identified or described by the customer is found, correct it before proceeding to the next steps (if possible).

4. Use an approved diagnostic system or scan tool (tester), to retrieve all DTCs before referring to the Symptom Table or DTC Index (DTC). Clear all DTCs after troubleshooting.

Symptom table

NOTE: See section 303-14 for a more complete symptom table "Electronic engine management system" in the workshop manual.

Symptom	Possible reason	Operation
Engine cranks and flashes but won't start	EVAP purge valve Fuel system Spark plug Malfunction (And) ignition coils	For purge valve checks, refer to the guided diagnostic program on the approved diagnostic system. Fuel system and ignition system checks are described in the relevant section of the workshop manual.
Cold start difficulties	Check the concentration of antifreeze in the cooling system Battery crankshaft position sensor (CKP) Fuel system EVAP purge valve	Check the condition of the coolant. For battery information, crankshaft position sensor and fuel system checks, see the appropriate sections in the workshop manual. For purge valve checks, refer to the guided diagnostic program on the approved diagnostic system.
Hot Start Difficulties	Nozzle leak Fuel system Fuel temperature sensor Air intake temperature sensor (IAT) Mass air flow sensor (MAF) EVAP purge valve Ignition system	Injector and fuel system checks, fuel temperature sensor, air intake temperature sensor, mass air flow sensor and ignition system are described in the appropriate sections of the workshop manual. For purge valve checks, refer to the guided diagnostic program on the approved diagnostic system.
Difficulty starting after a hot soak (the vehicle remains stationary for a while after the engine has reached operating temperature)	Nozzle leak Fuel system Fuel temperature sensor IAT sensor MAF sensor EVAP purge valve Ignition system	Injector and fuel system checks, fuel temperature sensor, air intake temperature sensor, mass air flow sensor and ignition system are described in the appropriate sections of the workshop manual. For purge valve checks, refer to the guided diagnostic program on the approved diagnostic system.

DTC index

NOTE: Universal Scan Tools cannot read the listed codes or can only read 5-digit codes. Match the 5 digits from the scan tool with the first 5 digits of the listed 7 digit code to identify the problem (the last 2 digits give additional information read by the diagnostic system approved by the manufacturer).

NOTE: See Section 303-14 for a complete list of ECM DTCs "Electronic engine management system" in the workshop manual.

DTC	Description	Possible reason	Operation
P044100	Evaporative Emission System - Incorrect Purge Flow Rate	Clogging / violation of the tightness of the pipeline of the purge valve of the adsorber of the fuel vapor recovery system (EVAP) Reducing the capacity of the adsorber ventilation duct Purge valve failure	Check the integrity of the pipelines and the canister ventilation system. See the relevant section of the workshop manual.
P044200	Leak detected in evaporative emission system (small leakage)	Fuel filler cap incorrectly installed Filler cap seal failure Leak in the evaporative emission system (adsorber, pipelines, etc.) Leak in the fuel tank Malfunction of the valve of dynamic control of leaks in a fuel tank (DMTL), located in the adsorber	See the relevant section of the workshop manual.
P044700	Rupture of an electric chain of management of ventilation of system of catching of steams of fuel	Short to ground EVAP DMTL valve circuit	Refer to the electrical manual and check the DMTl valve circuit. Repair/replace as needed. See the relevant section of the workshop manual.
P044800	Short circuit in the electrical control circuit of the ventilation of the evaporative emission system	Short to battery + EVAP DMTL valve circuit	Refer to the electrical manual and check the DMTl valve circuit. Repair/replace as needed. See the relevant section of the workshop manual.
P045500	Leak detected in evaporative emission system (big leak/no flow)	Fuel filler cap not installed Damaged/missing filler cap seal Leak in the evaporative emission system (adsorber, pipelines, etc.) Leak in the fuel tank DMTL valve failure	Check the fuel filler cap and seal, check the canister, piping, etc. Check the fuel tank for leaks, etc. See the relevant section of the workshop manual.
P045800	EVAP Purge Control Valve Circuit Low Voltage	Purge valve control circuit short to ground Purge valve control circuit high resistance Malfunction of the valve of a purge of an adsorber EVAP	Refer to the electrical manual and check the DMTl valve circuit. Repair/replace as needed. See the relevant section of the workshop manual. Refer to the guided diagnostic program for this code on the approved diagnostic system.
P045900	High voltage in the electrical circuit of the evaporative emission system purge control valve	Purge valve control circuit short to battery	Refer to the electrical manual and check the DMTl valve circuit. Repair/replace as needed. See the relevant section of the workshop manual. Refer to the guided diagnostic program for this code on the approved diagnostic system.
P240100	Low voltage in the electric control circuit of the pump for monitoring leaks in the evaporative emission system	Electrical circuit (chains) fuel tank leak control pump (DMTL): short circuit to ground Electrical circuit (chains) pump DMTL: high resistance	Check the wiring between the ECM and the DMTL pump according to the electrical manual. Make any necessary repairs.
P240200	High voltage in the electric control circuit of the pump for monitoring leaks in the evaporative emission system	Electrical circuit (chains) DMTL pump: short circuit to battery +	Check the wiring between the ECM and the DMTL pump according to the electrical manual. Make any necessary repairs.
P240429	EVAP Leak Detection Pump Electrical Range/Performance Problems	Reference leakage DMTL	Check the evaporative emission system for serviceability and tightness. Check DMTL pump and electrical circuits. Refer to the electrical manual. Finish checking the DMTL system. See the relevant section of the workshop manual.
P24042F	EVAP Leak Detection Pump Electrical Range/Performance Problems	Chaotic signal of the DMTL system	Check DMTL pump and electrical circuits. Refer to the electrical manual. See the relevant section of the workshop manual.
P240500	Low voltage in the signal circuit of the pump for monitoring leaks in the evaporative emission system	DMTL Pump Circuit Low Reference Circuit Voltage	Check the wiring between the ECM and the DMTL pump according to the electrical manual. Make any necessary repairs.
P240600	High voltage in the signal circuit of the leak control pump in the evaporative emission system	DMTL Pump Circuit High Reference Circuit Voltage	Check the wiring between the ECM and the DMTL pump according to the electrical manual. Make any necessary repairs.
P240B00	Low voltage in the electric circuit of the heating element of the leak control pump in the fuel vapor recovery system	Low voltage in the electrical control circuit of the heating element DMTl	Check the wiring between the ECM and the DMTL pump according to the electrical manual. Make any necessary repairs.
P240C00	High voltage in the heater circuit of the leak control pump in the evaporative emission system	High voltage in the electrical control circuit of the heating element DMTl	Check the wiring between the ECM and the DMTL pump according to the electrical manual. Make any necessary repairs.
P245000	Performance Problems/Stuck Open Evaporative Emission System Multi-Way Valve	DMTL pump circuit short circuit high resistance Malfunction of the switching valve of the DMTL system	Check the wiring between the ECM and the DMTL valve according to the electrical manual. Repair/replace as needed. See the relevant section of the workshop manual.
P245100	Evaporative emission multi-way valve sticking closed	DMTL pump circuit short circuit high resistance Malfunction of the switching valve of the DMTL system	Check the wiring between the ECM and the DMTL valve according to the electrical manual. Repair/replace as needed. See the relevant section of the workshop manual.