Diagnostics and testing 4.0L (Discovery 3)

Inspection and verification

1. Check the validity of the customer's complaint.

2. Perform a visual inspection to detect obvious signs of mechanical or electrical damage.

Mechanical factors	Electrical factors
Fuel leaks Damaged fuel lines Damaged fittings Fuel level Fuel contamination/fuel brand/fuel quality Throttle body Damaged fuel tank filler cap Damaged fuel tank filler neck	Fuses and fuses Inertia switch Loose or corroded electrical connectors Wiring harnesses Sensor(s) Engine Control Module (ECM)

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 an approved diagnostic system or scanning device (tester) to read all Diagnostic Trouble Codes (DTCs) before proceeding to the Fault Indication Table or DTC Code Index.

Clear all DTCs after troubleshooting.

Table of signs of malfunction

Sign of malfunction	Possible reasons	Action
The engine crankshaft turns over, but no sparks occur.	Low fuel level/contamination Ignition system Fuel system Crankshaft Position Sensor (CKP) Wiring harness ECM failure	Check the fuel level and condition. For information on ignition system inspections, refer to the relevant section in the Service station manual. Check for DTC codes for injectors. CKP and wiring harness checks. Refer to the corresponding section in the service station manual. If a module is suspected, please refer to the Warranty Service Policies and Procedures manual.
The engine crankshaft turns, flashes occur, but the engine does not start	Fuel Evaporative Emission Control System Canister Purge Valve Fuel system Spark plugs Ignition coil fault(s)	For information on purge valve inspections, refer to the relevant section in the Service station manual. Check for DTC codes for injectors. For information on ignition system inspections, refer to the relevant section in the Service station manual.
Difficulty starting when cold	Check the concentration of antifreeze in the cooling system Battery Crankshaft Position Sensor (CKP) Fuel system Fuel Evaporative Emission Control System Canister Purge Valve	For information about the battery, refer to the appropriate section in the service station manual. For information on CKP sensor inspections, refer to the corresponding section in the Service station manual. Check for DTC codes for injectors. For information on purge valve inspections, refer to the relevant section in the Service station manual.
Difficulty starting when hot	Leak in the injector Fuel system Fuel temperature sensor Intake Air Temperature (IAT) Sensor Mass Air Flow (MAF) Sensor Fuel Evaporative Emission Control System Canister Purge Valve Ignition system	Check for DTC codes for injectors. For information on testing the fuel temperature sensor, IAT sensor, and MAF sensor, refer to the corresponding section in the Service station manual. For information on purge valve and ignition system checks, refer to the relevant section in the Service station manual.
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 Fuel Evaporative Emission Control System Canister Purge Valve Ignition system	Check for DTC codes for injectors. For information on testing the fuel temperature sensor, IAT sensor, and MAF sensor, refer to the corresponding section in the Service station manual. For information on purge valve and ignition system checks, refer to the relevant section in the Service station manual.
Engine stalls shortly after starting	Disconnection/reduction of ventilation system capacity ECM relay MAF sensor Fuel Rail Pressure (FRP) Sensor Ignition system Clogged air filter Air leak Fuel lines	Check the engine ventilation system. Check the operation of the ECM relay. For information on checking the MAF and FRP sensors and the ignition system, refer to the appropriate section in the service manual. For information on the air intake system and fuel lines, refer to the appropriate section in the service manual.
Engine lag/poor acceleration	Fuel pump Fuel lines Leak in the injector Fuel pressure Air leak Throttle Position (TP) Sensors Accelerator Pedal Position Sensor (APP) Throttle body motor Ignition system HO2 sensors Gearbox failure Limited pedal travel (floor mat, etc.)	For information about the fuel pump and fuel lines, refer to the corresponding section in the Service station manual. Check for DTC codes for injectors. For information on checking the intake system, TP sensor, and APP sensor, refer to the corresponding section in the Service station manual. For information on checking the throttle motor, refer to the directional diagnostic program in an approved diagnostic system. For information on ignition system inspections, refer to the relevant section in the Service station manual. Check for DTC codes for HO2 sensors, refer to the DTC Code Index. For more information about the gearbox, refer to the corresponding section in the service station manual. Check the accelerator pedal speed.
Backfires in the engine	Fuel pump Fuel lines Air leak MAF sensor APP sensor HO2 sensors Ignition system	For information about the fuel pump, fuel lines, and air intake system, refer to the corresponding section in the Service station manual. For information about checking the MAF sensor and the APP sensor, refer to the corresponding section in the Service station manual. Check for DTC codes for HO2 sensors, refer to the DTC Code Index. For information on ignition system inspections, refer to the relevant section in the Service station manual.
Engine jerks	Fuel pump Fuel lines MAF sensor Wiring harness TP sensors Throttle body motor Ignition system	For information about the fuel pump and fuel lines, refer to the corresponding section in the Service station manual. For information about checking the MAF sensor and TP sensor, refer to the corresponding section in the Service station manual. For information on checking the throttle motor, refer to the directional diagnostic program in an approved diagnostic system. For information on ignition system inspections, refer to the relevant section in the Service station manual.
Detonation/knocking in the engine	Fuel pump Fuel lines Fuel quality Knock sensor (KS)/electrical circuit malfunction FRP sensor MAF sensor HO2 sensors Air leak BARO sensor malfunction (internal ECM failure)	For information about the fuel pump and fuel lines, refer to the corresponding section in the Service station manual. For information on testing the FRP sensor, MAF sensor, and knock sensor, refer to the corresponding section in the Service station manual. Check for DTC codes for HO2 sensors, refer to the DTC Code Index. For information about the air intake system, refer to the corresponding section in the Service station manual. If a module is suspected, please refer to the Warranty Service Policies and Procedures manual.
Lack of throttle response	APP sensor failure TP sensors Throttle body motor	For information on APP sensor and TP sensor tests, refer to the appropriate section in the workshop manual. For information on throttle motor tests, refer to the guided diagnostic routine on the approved diagnostic system.
Poor throttle response	APP sensor failure TP sensors ECT sensor MAF sensor Gearbox failure Activating the traction control system Air leak Disconnection/reduction of ventilation system capacity	For information on testing the APP sensor, TP sensor, ECT sensor, and MAF sensor, refer to the appropriate section in the workshop manual. For information on the transmission, refer to the appropriate section in the workshop manual. For information on testing the air intake system, refer to the appropriate section in the workshop manual. For information on testing the ventilation system, refer to the appropriate section in the workshop manual.

DTC Index

NOTE: Generic scan tools may not be able to read the codes listed or may only be able to 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 an approved diagnostic system).

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

DTC	Description	Possible reasons	Action
P017100	Too much leanness in the system (cylinder bank 1)	Leak in the air intake system between the MAF sensor and the cylinder head MAF sensor malfunction (low intake air flow) Reduced fuel filter/fuel system flow capacity Low fuel pressure Clogged fuel injector Leak in the exhaust system (before the catalytic converter) Fuel Evaporative Emissions Control System Malfunction	Check the air intake system for leaks, etc. Check the fuel system for reduced flow, DTCs, etc. Check the exhaust system for leaks, etc. Check for DTCs for the evaporative emission control system
P017200	Too much enrichment in the system (cylinder bank 1)	Reducing the air filter capacity High fuel pressure Leaking fuel injector(s) Oil contamination with fuel (too many cold starts without allowing the vehicle to reach a high enough temperature for a sufficiently long time) MAF sensor malfunction Fuel Evaporative Emissions Control System Malfunction	Check the air intake system for restriction, etc. Check the fuel system for leaks, DTCs, etc. Check the oil condition. Check for DTCs for the MAF sensor and the evaporative emission control system.
P017400	Too much leanness in the system (cylinder bank 2)	Leak in the air intake system between the mAf sensor and the cylinder head MAF sensor malfunction (low intake air flow) Reduced fuel filter/fuel system flow capacity Low fuel pressure Clogged fuel injector Leak in the exhaust system (before the catalytic converter) Fuel Evaporative Emissions Control System Malfunction	Check the air intake system for leaks, etc. Check the fuel system for reduced flow, DTCs, etc. Check the exhaust system for leaks, etc. Check for DTCs for the evaporative emission control system.
P017500	Too much enrichment in the system (cylinder bank 2)	Reducing the air filter capacity High fuel pressure Leaking fuel injector(s) Oil contamination with fuel (too many cold starts without allowing the vehicle to reach a high enough temperature for a sufficiently long time) MAF sensor malfunction Fuel Evaporative Emissions Control System Malfunction	Check the air intake system for restriction, etc. Check the fuel system for leaks, DTCs, etc. Check the oil condition. Check for DTCs for the MAF sensor and the evaporative emission control system.
P020100	Open circuit of injector cylinder #1	The injector is disconnected Injector wiring: high resistance, short to ground Injector malfunction	For fuel system testing information, refer to the appropriate section in the service manual. Refer to the guided diagnostic routine for this code on the approved diagnostic system.
P020200	Open circuit of injector cylinder #2	The injector is disconnected Injector wiring: high resistance, short to ground Injector malfunction	For fuel system testing information, refer to the appropriate section in the service manual. Refer to the guided diagnostic routine for this code on the approved diagnostic system.
P020300	Open circuit of injector cylinder #3	The injector is disconnected Injector wiring: high resistance, short to ground Injector malfunction	For fuel system testing information, refer to the appropriate section in the service manual. Refer to the guided diagnostic routine for this code on the approved diagnostic system.
P020400	Open circuit of injector cylinder #4	The injector is disconnected Injector wiring: high resistance, short to ground Injector malfunction	For fuel system testing information, refer to the appropriate section in the service manual. Refer to the guided diagnostic routine for this code on the approved diagnostic system.
P020500	Open circuit of injector cylinder #5	The injector is disconnected Injector wiring: high resistance, short to ground Injector malfunction	For fuel system testing information, refer to the appropriate section in the service manual. Refer to the guided diagnostic routine for this code on the approved diagnostic system.
P020600	Open circuit of injector cylinder #6	The injector is disconnected Injector wiring: high resistance, short to ground Injector malfunction	For fuel system testing information, refer to the appropriate section in the service manual. Refer to the guided diagnostic routine for this code on the approved diagnostic system.
P210129	Problems with the operating range/ characteristics of the electric circuit of the electric motor controlling the throttle actuator A	Throttle valve, gearbox or electric motor sticking	Check for fuel system DTCs and for a message in the instrument cluster. Repair if necessary. If the problem persists, replace the throttle body. Refer to the appropriate section in the service manual.
P210164	Problems with the operating range/ characteristics of the electric circuit of the electric motor controlling the throttle actuator A	Throttle valve, gearbox or electric motor sticking	Check for fuel system DTCs and for a message in the instrument cluster. Repair if necessary. If the problem persists, replace the throttle body. Refer to the appropriate section in the service manual.
P210329	High voltage in the electrical circuit of the electric motor controlling the throttle actuator A	Electrical control circuit of the throttle actuating device: battery short circuit ECM failure	Check the electric throttle body and electrical circuits. Refer to the electrical manual. Clear DTCs and verify proper operation. Refer to the guided diagnostic routine for this code on the approved diagnostic system. If the ECM is suspected, refer to the warranty policy and procedures manual.
P210364	High voltage in the electrical circuit of the electric motor controlling the throttle actuator A	Control circuit: short circuit to battery + ECM failure	Check the electric throttle body and electrical circuits. Refer to the electrical manual. Clear DTCs and verify proper operation. Refer to the guided diagnostic routine for this code on the approved diagnostic system. If the ECM is suspected, refer to the warranty policy and procedures manual.
P210500	Throttle actuator control system - forced engine shutdown	Throttle MIL Request Due to Fuel Cut	Check for DTCs that indicate the cause of the fuel cutoff. Perform the actions specified for those DTCs.
P210629	Electric throttle control system - forced engine shutdown	Throttle MIL Request Due to Fuel Cut	Check for DTCs that indicate the cause of the fuel cutoff. Perform the actions specified for those DTCs.
P210664	Throttle actuator control system - forced power limitation	Intentional limitation of functionality (emergency mode "limp home")	Check for fuel system DTCs and for a message in the instrument cluster. Repair if necessary. If the problem persists, replace the throttle body. Refer to the appropriate section in the service manual.
P211800	Problems with the operating range/ current characteristics of the electric motor controlling the throttle actuator	Throttle Motor Over Current Condition Registered ECM failure	Refer to the electrical manual and check the wiring between the ECM and the throttle actuator. Refer to the guided diagnostic routine for this code on the approved diagnostic system. If ECM malfunction is suspected, refer to the warranty policy and procedures manual.
P211900	Throttle body operating range/performance issues in regards to throttle actuator control	Throttle spring failure	Check the throttle return spring on the throttle body. Repair/ replace as needed. Check for DTC codes for the fuel supply system and for a message on the instrument panel. Repair it if necessary. If the problem persists, replace the throttle body. refer to the corresponding section in the service station manual.