Diagnostics and testing of the fuel supply system (Defender 2007+)

Inspection and verification

WARNING: Observe all appropriate safety precautions when working on the fuel system. Failure to observe this warning could result in personal injury.

CAUTION: When working with these items, maintain absolute cleanliness. Always plug any open holes or lines. Failure to follow this instruction may result in damage to the vehicle.

1. Check the customer complaint.

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

Visual inspection

Mechanical elements	Electrical equipment
• Low fuel level/contamination • Fuel supply/return line(s) • Fuel tank and filler pipe • Fuel leak(s) • Fuel tank filler cap • Fuel filter • Push-to-connect fittings • Fuel pressure regulator • Fuel manifold • Fuel injection pump • Exhaust Gas Recirculation (EGR) system	• Fuses • Glow plug indicator light • Inertial Fuel Shut-off Sensor (IFS) • Sensor(s) • Engine Control Module (ECM) • Fuel suction control valve • Fuel rail pressure sensor • Fuel temperature sensor • Fuel injector(s) • EGR system

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

4. Before referring to the symptom chart or diagnostic trouble code (DTC) index, read all DTCs with a validated diagnostic system or scan tool.

• Clear all DTCs after troubleshooting.

Table of signs of malfunction

Sign	Possible reasons	Operation
The crankshaft turns but the engine does not start	Engine control unit power relay Inertial Fuel Shutoff Sensor (IFS) Low fuel level/contamination Air leak Malfunction in the low pressure fuel system Clogged fuel filter Blocked/contaminated fuel suction control valve High pressure fuel pump malfunction Crankshaft Position Sensor (CKP)	Check if the inertia switch is activated. Check if DTC P068A-00 is set (Engine Control Unit Power Relay De-energization: Early On). See the DTC help. Check the ECM main relay and electrical circuits. Refer to the electrical equipment manual. Check the fuel level and condition. Drain approximately 1 liter of fuel and let it sit for 1 minute. Make sure that there is no separation indicating the presence of water or other liquid in the fuel. Check the air intake system for leaks. Check the low-pressure fuel system for leaks/ damage. Check the fuel filter, check for DTC codes indicating a fuel pump malfunction. Check the high pressure fuel pump: For more information, refer to: Fuel Pump (303-04A Fuel Supply and Controls - ID4 2.4L Diesel Engine, Removal and Installation). Check the CKP sensor circuits. Refer to the electrical manuals. Install a new crankshaft position (CKP) sensor if necessary. For more information, refer to: Crankshaft Position (CKP) Sensor (303-14 Electronic controls - Diesel engine ID4 2.4L, Removal and installation).
Difficult start	Malfunction of the glow plug system (very low temperature conditions) Low fuel level/contamination Air leak Malfunction in the low pressure fuel system Clogged fuel filter Blocked/contaminated fuel suction control valve Exhaust Gas Recirculation (EGR) valve(s) faulty	NOTE: Make sure that the latest version of the EGR throttle intake valve is installed. Use a manufacturer-approved diagnostic system to check and install the latest version of the software on the engine control unit. Check the electrical circuits of the preheating candles. Refer to the electrical equipment manuals. Check the fuel level/ condition. Drain approximately 1 liter of fuel and let it sit for 1 minute. Make sure that there is no separation indicating the presence of water or other liquid in the fuel. Check the air intake system for leaks. Check the low-pressure fuel system for leaks/ damage. Check the fuel filter, check for DTCs indicating a malfunction of the fuel intake control valve. EGR Valve Inspections: For more information, refer to: Reducing Exhaust toxicity (303-08 Emission Control - ID4 2.4L Diesel Engine, Diagnostics and Tests).
Rough idle operation	Air intake system malfunction Low fuel level/contamination Malfunction in the low pressure fuel system Clogged fuel filter Blocked/contaminated fuel suction control valve Exhaust Gas Recirculation (EGR) valve(s) faulty	NOTE: Ensure that the latest version of the EGR throttle valve is installed. Using the manufacturer approved diagnostic system, check and install the latest software version on the engine control module. Check the air intake system for leaks. Check the fuel level/condition. Drain approximately 1 liter of fuel and let it sit for 1 minute. Make sure that there is no separation indicating the presence of water or other liquid in the fuel. Check the low-pressure fuel system for leaks/ damage. Check the fuel filter, check for DTCs indicating a malfunction of the fuel intake control valve. EGR Valve Inspections: For more information, refer to: Reducing Exhaust toxicity (303-08 Emission Control - ID4 2.4L Diesel Engine, Diagnostics and Tests).
Ned remaining power during acceleration	Air intake system malfunction Clogged exhaust system Low fuel pressure Exhaust Gas Recirculation (EGR) valve(s) faulty Turbocharger actuator failure	NOTE: Ensure that the latest version of the EGR throttle inlet valve is installed. Using the manufacturer approved diagnostic system, check and install the latest software version on the ECM. Check the air intake system for leaks or blockages. Check the exhaust system for blockages/obstructions, install new components if necessary. For more information, refer to: Catalytic Converter (309-00 Exhaust system - Diesel engine ID4 2.4L, Removal and installation). Check for diagnostic trouble codes (DTCs) indicating incorrect fuel pressure. For EGR valve tests: For more information, refer to: Emission Control (303-08 Emission Control - ID4 2.4L Diesel Engine, Diagnostics and Tests). check if the variable geometry turbocharger actuator lever moves. For more information, refer to: Turbocharger actuator rod (303-04B Fuel Delivery and Controls - Turbocharger - ID4 2.4L Diesel Engine, Removal and Installation). For turbocharger actuator checks: For additional information, refer to: Turbocharger (303-04B Fuel Delivery and Controls - Turbocharger - ID4 2.4L Diesel Engine,
Engine stops/stalls	Air leak Low fuel level/contamination Malfunction in the low pressure fuel system High pressure fuel leak Blocked/contaminated fuel injection valve Exhaust Gas Recirculation (EGR) Valve Malfunction	NOTE: Ensure that the latest version of the EGR throttle inlet valve is installed. Using the manufacturer approved diagnostic system, check and install the latest software version on the ECM. Check the air intake system for leaks. Check the fuel level/condition. Drain approximately 1 liter of fuel and let it sit for 1 minute. Make sure that there is no separation indicating the presence of water or other liquid in the fuel. Check the fuel system for leaks/ damage. Check for DTC codes that indicate a malfunction of the fuel intake control valve. EGR Valve Inspections: For more information, refer to: Reducing Exhaust toxicity (303-08 Emission Control - ID4 2.4L Diesel Engine, Diagnostics and Tests).
Engine vibration	Low fuel level/contamination Air intake Malfunction in the low pressure fuel system Blocked/contaminated fuel injection valve High pressure fuel leak High pressure fuel pump malfunction	Check the fuel level/condition. Drain approximately 1 liter of fuel and let it sit for 1 minute. Make sure that there is no separation indicating the presence of water or other liquid in the fuel. Check the air intake system for leaks. Check the low-pressure fuel system for leaks/ damage. Check the high-pressure fuel system for leaks. Check for DTC codes that indicate a malfunction of the fuel intake control valve. Check the high pressure fuel pump: For more information, refer to: Fuel Pump (303-04A Fuel Supply and Controls - ID4 2.4L Diesel Engine, Removal and Installation).
Excessive fuel consumption	Malfunction in the low pressure fuel system Blocked/contaminated fuel injection valve Fuel temperature sensor leak High pressure fuel leak Injector(s) malfunction Exhaust Gas Recirculation (EGR) valve(s) faulty	NOTE: Ensure that the latest version of the EGR throttle inlet valve is installed. Using the manufacturer approved diagnostic system, check and install the latest software version on the ECM. Check the low pressure fuel system for leaks/damage. Check for DTCs indicating a faulty fuel suction control valve. Check the fuel temperature sensor, high pressure fuel pump, etc. for leaks. Check for injector related DTCs. EGR valve checks: For more information, refer to: Emission Control (303-08 Emission Control - ID4 2.4L Diesel Engine, Diagnostics and Tests).

For a complete list of diagnostic trouble codes that may be stored in the vehicle, see Section 100-00. For additional information, refer to: How to Use This Manual (100-00 General information, Description and operating principle).