Diagnostics and testing 4.4L (Discovery 3)

Inspection and verification

1. Check the validity of the customer complaint. Keep in mind that the vehicle has a number of systems that communicate with the message center, giving the driver information that is useful in diagnosing faults.

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

Mechanical factors	Electrical factors
Fuel tank filler cap and seal Fuel tank 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 and fuses Electrical connectors Wiring harness(es) Purge valve DMTL pump

3. If an obvious cause for the problem you identified or the customer described is found, correct it before proceeding with further actions. (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

NOTE: For a more complete troubleshooting chart, refer to Section 303-14, Electronic Engine Management System, in the Service Manual.

Sign of malfunction	Possible reason	Operation
The engine turns over and flashes but does not start.	EVAP purge valve Fuel system Spark plugs Ignition coil fault(s)	For purge valve tests, refer to the guided diagnostic program on the approved diagnostic system. Fuel and ignition system tests are described in the appropriate section of the workshop manual.
Difficulty starting at cold start	Check the concentration of antifreeze in the cooling system Battery Crankshaft Position Sensor (CKP) Fuel system EVAP purge valve	Check the coolant condition. For battery information, crankshaft position sensor and fuel system tests, refer to the appropriate sections of the workshop manual. For purge valve tests, refer to the guided diagnostic program on the approved diagnostic system.
Difficulty with hot start	Leak in the injector Fuel system Fuel temperature sensor Intake Air Temperature (IAT) sensor Mass Air Flow (MAF) Sensor EVAP purge valve Ignition system	Injector and fuel system, fuel temperature sensor, air intake temperature sensor, mass air flow sensor, and ignition system tests are described in the appropriate sections of the workshop manual. For purge valve tests, refer to the guided diagnostic routine on the approved diagnostic system.
Difficulty starting after hot soak (the car remains stationary for some time after the engine has reached operating temperature)	Leak in the injector Fuel system Fuel temperature sensor IAT sensor MAF sensor EVAP purge valve Ignition system	Injector and fuel system, fuel temperature sensor, air intake temperature sensor, mass air flow sensor, and ignition system tests are described in the appropriate sections of the workshop manual. For purge valve tests, refer to the guided diagnostic routine on the approved diagnostic system.

DTC Index

NOTE: Generic scan tools cannot read the codes listed 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 fault. (the last 2 digits provide additional information readable by a manufacturer approved diagnostic system).

NOTE: For a complete listing of ECM DTCs, refer to Section 303-14, Electronic Engine Control System, in the service manual.

DTC	Description	Possible cause	Operation
P044100	Fuel Evaporative Recovery System - Incorrect Purge Flow Rate	Fuel vapor capture system (EVAP)Purge valve pipeline is clogged/leaky Reducing the capacity of the adsorber ventilation duct Purge valve malfunction	Check the integrity of the pipes and the ventilation system of the adsorber. See the relevant section of the service station manual.
P044200	A leak has been detected in the fuel vapor recovery system. (small leak)	The fuel filler cap is not installed correctly. Filler cap seal failure Leak in the fuel vapor recovery system (adsorber, pipelines, etc.) Leak in the fuel tank Malfunction of the dynamic leak control valve in the fuel tank (DMTL) located in the canister	Please refer to the relevant section of the service station manual.
P044700	Open circuit in the electrical control circuit of the ventilation of the fuel vapor recovery system	EVAP DMTL Valve Circuit Short to Ground	Refer to the electrical manual and check the DMTl valve circuit. Repair/replace as necessary. Refer to the relevant section of the workshop manual.
P044800	Short circuit in the fuel vapor recovery system ventilation control circuit	EVAP DMTL Valve Circuit Short to Battery +	Refer to the electrical manual and check the DMTl valve circuit. Repair/replace as necessary. Refer to the relevant section of the workshop manual.
P045500	A leak has been detected in the fuel vapor recovery system. (large leak/no flow)	Fuel filler cap not installed Damage/missing seal on the filler cap Leak in the fuel vapor recovery system (adsorber, pipelines, etc.) Leak in the fuel tank DMTL valve failure	Check the cap and seal of the fuel filler cap, check the adsorber, piping, etc. Check the fuel tank for leaks, etc. See the relevant section of the service station manual.
P045800	Low Voltage in Evaporative Emission Control Valve Circuit	Purge Valve Control Circuit Short to Ground Purge Valve Control Circuit High Resistance EVAP Canister Purge Valve Malfunction	Refer to the electrical manual and check the DMTl valve circuit. Repair/replace as necessary. Refer to the appropriate section of the workshop manual. Refer to the guided diagnostic routine for this code on the approved diagnostic system.
P045900	High Voltage in Evaporative Emission Control Valve Circuit	Purge valve control circuit: short circuit to battery +	Refer to the electrical manual and check the DMTl valve circuit. Repair/replace as necessary. Refer to the appropriate section of the workshop manual. Refer to the guided diagnostic routine for this code on the approved diagnostic system.
P240100	Low voltage in the fuel vapor recovery system leak control pump control circuit	Fuel Tank Leak Detection Pump (DMTL) Circuit(s) Short to Ground DMTL Pump Circuit(s): High Resistance	According to the electrical manual, check the wiring between the ECM and the DMTL pump. Make necessary repairs.
P240200	High voltage in fuel vapor recovery system leak control pump control circuit	DMTL pump electrical circuit(s): short circuit to battery +	According to the electrical manual, check the wiring between the ECM and the DMTL pump. Make necessary repairs.
P240429	Fuel Evaporative Emission System Leak Detection Pump Sensing Circuit Range/Performance Problems	DMTL Reference Leak	Check the fuel vapor recovery system for serviceability and leaks. Check the DMTL pump and electrical circuits. Refer to the electrical equipment manual. Complete the DMTL system check. Refer to the appropriate section of the service manual.
P24042F	Fuel Evaporative Emission System Leak Detection Pump Sensing Circuit Range/Performance Problems	Chaotic signal of DMTL system	Check the DMTL pump and electrical circuits. Refer to the electrical equipment manual. See the relevant section of the service station manual.
P240500	Low Voltage in Evaporative Emission System Leak Detection Pump Signal Circuit	DMTL Pump Electrical Circuit: Low Voltage Reference Circuit	According to the electrical manual, check the wiring between the ECM and the DMTL pump. Make necessary repairs.
P240600	Fuel Evaporative Emission System Leak Detection Pump Signal Circuit High Voltage	DMTL Pump Electrical Circuit: High Voltage in Reference Circuit	According to the electrical manual, check the wiring between the ECM and the DMTL pump. Make necessary repairs.
P240B00	Low voltage in the heating element circuit of the leak control pump in the fuel vapor recovery system	Low voltage in the control circuit of the heating element DMTl	According to the electrical manual, check the wiring between the ECM and the DMTL pump. Make necessary repairs.
P240C00	Fuel Evaporative Emission System Leak Detection Pump Heater Circuit High Voltage	High voltage in the control circuit of the heating element DMTl	According to the electrical manual, check the wiring between the ECM and the DMTL pump. Make necessary repairs.
P245000	Performance issues/vaporative emission system multi-way valve stuck open	DMTL Pump Electrical Circuit: Short Circuit, High Resistance DMTL system switching valve malfunction	In accordance with the electrical manual, check the wiring between the ECM and the DMTL valve. Repair/replace as necessary. Refer to the relevant section of the workshop manual.
P245100	Fuel vapor recovery system multi-way valve stuck in closed position	DMTL Pump Electrical Circuit: Short Circuit, High Resistance DMTL system switching valve malfunction	In accordance with the electrical manual, check the wiring between the ECM and the DMTL valve. Repair/replace as necessary. Refer to the relevant section of the workshop manual.