Diagnosis and check 4.0L (Discovery 3)

Inspection and verification

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

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

Mechanical factors	Electrical Factors
Fuel leaks Damaged fuel lines Damaged fittings Fuel level Fuel contamination / fuel grade / fuel quality throttle body Damaged fuel filler cap Damaged fuel filler pipe	Fuses Inertial switch Loose or corroded electrical connectors Wiring harnesses Sensor (And) The engine control unit (ECM)

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

4. Use an approved diagnostic system or scan tool (tester), to read all diagnostic trouble codes (DTC) before going to the Symptom Table or DTC Index.

Clear all DTCs after troubleshooting.

Symptom table

Symptom	Possible reasons	Action
The crankshaft of the engine scrolls, but flashes do not occur	Low/contaminated fuel Ignition system Fuel system crankshaft position sensor (CKP) Wiring harness ECM malfunction	Check the level and condition of the fuel. For information on ignition system checks, refer to the relevant section in the workshop manual. Check for injector DTCs. CKP and wiring harness checks. Refer to the relevant section in the workshop manual. If a module is suspected, refer to the warranty policy and procedures manual.
The crankshaft of the engine scrolls, there are flashes, but the engine does not start	Evaporative canister purge valve Fuel system Spark plug Malfunction (And) ignition coils	For information on purge valve checks, refer to the appropriate section in the service station manual. Check for injector DTCs. For information on ignition system checks, refer to the relevant section in the workshop manual.
Difficult cold start	Check the concentration of antifreeze in the cooling system Battery crankshaft position sensor (CKP) Fuel system Evaporative canister purge valve	For battery information, refer to the appropriate section in the workshop manual. For information on CKP sensor checks, refer to the appropriate section in the workshop manual. Check for injector DTCs. For information on purge valve checks, refer to the appropriate section in the service station manual.
Difficulty starting when hot	Nozzle leak Fuel system Fuel temperature sensor Intake air temperature sensor (IAT) Mass air flow sensor (MAF) Evaporative canister purge valve Ignition system	Check for injector DTCs. For fuel temperature sensor, IAT sensor, and MAF sensor checks, refer to the appropriate section in the workshop manual. For information on purge valve and ignition system checks, refer to the appropriate section in the workshop manual.
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 Evaporative canister purge valve Ignition system	Check for injector DTCs. For fuel temperature sensor, IAT sensor, and MAF sensor checks, refer to the appropriate section in the workshop manual. For information on purge valve and ignition system checks, refer to the appropriate section in the workshop manual.
Engine stalls shortly after starting	Disconnection / reduction of ventilation system capacity ECM relay MAF sensor Fuel rail pressure sensor (FRP) Ignition system Clogged air filter Air leakage Fuel lines	Check engine ventilation system. Check the operation of the ECM relay. For MAF and FRP sensor and ignition system checks, refer to the appropriate section in the workshop manual. For information on the air intake system and fuel lines, refer to the appropriate section in the workshop manual.
Engine acceleration lag/poor acceleration	Fuel pump Fuel lines Nozzle leak Fuel pressure Air leakage Throttle Position Sensors (TR) Accelerator pedal position sensor (APP) Throttle Motor Ignition system HO2 sensors Transmission malfunction Limited pedal travel (floor mat, etc.)	For information about the fuel pump and fuel lines, refer to the appropriate section in the workshop manual. Check for injector DTCs. For air intake system, TP sensor, and APP sensor checks, refer to the appropriate section in the workshop manual. Refer to the guided diagnostic program on the approved diagnostic system for throttle motor checks. For information on ignition system checks, refer to the relevant section in the workshop manual. Check for DTCs for HO2 sensors, refer to the DTC Index. For gearbox information, refer to the appropriate section in the workshop manual. Check the travel of the accelerator pedal.
Backfires in the engine	Fuel pump Fuel lines Air leakage MAF sensor APP sensor HO2 sensors Ignition system	For information about the fuel pump, fuel lines and air intake system, refer to the appropriate section in the workshop manual. For MAF sensor and APP sensor checks, refer to the appropriate section in the workshop manual. Check for DTCs for HO2 sensors, refer to the DTC Index. For information on ignition system checks, refer to the relevant section in the workshop manual.
Engine Jerks	Fuel pump Fuel lines MAF sensor Wiring harness TP sensors Throttle motor Ignition system	For information about the fuel pump and fuel lines, refer to the appropriate section in the workshop manual. For MAF sensor and TP sensor checks, refer to the appropriate section in the workshop manual. Refer to the guided diagnostic program on the approved diagnostic system for throttle motor checks. For information on ignition system checks, refer to the relevant section in the workshop manual.
Detonation / knocking in the engine	Fuel pump Fuel lines Fuel quality Knock sensor malfunction (KS) / electrical circuit FRP sensor MAF sensor HO2 sensors Air leakage BARO sensor malfunction (internal ECM malfunction)	For information about the fuel pump and fuel lines, refer to the appropriate section in the workshop manual. For FRP sensor, MAF sensor, and knock sensor checks, refer to the appropriate section in the workshop manual. Check for DTCs for HO2 sensors, refer to the DTC Index. For information about the air intake system, refer to the appropriate section in the workshop manual. If a module is suspected, refer to the warranty policy and procedures manual.
Lack of throttle response	APP sensor malfunction TP sensors Throttle Motor	For information on APP sensor and TP sensor checks, refer to the appropriate section in the workshop manual. Refer to the guided diagnostic program on the approved diagnostic system for throttle motor checks.
Poor throttle response	APP sensor malfunction TP sensors ECT sensor MAF sensor Transmission malfunction Traction control activation Air leakage Disconnection / reduction of ventilation system capacity	For APP sensor, TP sensor, ECT sensor, and MAF sensor checks, refer to the appropriate section in the workshop manual. For gearbox information, refer to the appropriate section in the workshop manual. For air intake system checks, refer to the appropriate section in the workshop manual. For information on ventilation system checks, refer to the relevant section in the service station manual.

DTC index

NOTE: Universal Scan Tools may not read the listed codes or may 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 approved diagnostic system).

NOTE: For a complete list of ECM DTCs, refer to Section 303-14 - "Electronic engine controls" in the workshop manual.

DTC	Description	Possible reasons	Action
P017100	Too much lean in the system (cylinder bank 1)	Air intake leak between MAF sensor and cylinder head MAF sensor malfunction (low intake air flow) Reducing the capacity of the fuel filter / fuel system Low fuel pressure Clogged fuel injector Leak in the exhaust system (before the catalytic converter) Malfunction of the fuel vapor control system	Check the air intake system for leaks, etc. Check the fuel system for reduced capacity, DTCs, etc. Check the exhaust system for leaks, etc. Check for DTCs for the fuel vapor control system
P017200	Too much enrichment in the system (cylinder bank 1)	Reducing the capacity of the air filter High fuel pressure Fuel injector leak (Oh) Oil contamination with fuel (too many cold starts without bringing the car up to a high enough temperature for a long enough time) MAF sensor malfunction Malfunction of the fuel vapor control system	Check the air intake system for reduced capacity, etc. Check the fuel system for leaks, DTCs, etc. Check the condition of the oil. Check for DTCs for the MAF sensor and the fuel vapor control system.
P017400	Too much lean in the system (cylinder bank 2)	Leak in air intake system between mAf sensor and cylinder head MAF sensor malfunction (low intake air flow) Reducing the capacity of the fuel filter / fuel system Low fuel pressure Clogged fuel injector Leak in the exhaust system (before the catalytic converter) Malfunction of the fuel vapor control system	Check the air intake system for leaks, etc. Check the fuel system for reduced capacity, DTCs, etc. Check the exhaust system for leaks, etc. Check for DTCs for the fuel vapor control system.
P017500	Too much enrichment in the system (cylinder bank 2)	Reducing the capacity of the air filter High fuel pressure Fuel injector leak (Oh) Oil contamination with fuel (too many cold starts without bringing the car up to a high enough temperature for a long enough time) MAF sensor malfunction Malfunction of the fuel vapor control system	Check the air intake system for reduced capacity, etc. Check the fuel system for leaks, DTCs, etc. Check the condition of the oil. Check for DTCs for the MAF sensor and the fuel vapor control system.
P020100	Cylinder No. 1 injector open circuit	Nozzle disconnected Injector wiring high resistance, short to ground Injector failure	For information on fuel system checks, refer to the appropriate section in the workshop manual. Refer to the guided diagnostic program for this code on the approved diagnostic system.
P020200	Cylinder No. 2 injector open circuit	Nozzle disconnected Injector wiring high resistance, short to ground Injector failure	For information on fuel system checks, refer to the appropriate section in the workshop manual. Refer to the guided diagnostic program for this code on the approved diagnostic system.
P020300	Cylinder No. 3 injector open circuit	Nozzle disconnected Injector wiring high resistance, short to ground Injector failure	For information on fuel system checks, refer to the appropriate section in the workshop manual. Refer to the guided diagnostic program for this code on the approved diagnostic system.
P020400	Cylinder No. 4 injector open circuit	Nozzle disconnected Injector wiring high resistance, short to ground Injector failure	For information on fuel system checks, refer to the appropriate section in the workshop manual. Refer to the guided diagnostic program for this code on the approved diagnostic system.
P020500	Cylinder No. 5 injector open circuit	Nozzle disconnected Injector wiring high resistance, short to ground Injector failure	For information on fuel system checks, refer to the appropriate section in the workshop manual. Refer to the guided diagnostic program for this code on the approved diagnostic system.
P020600	Cylinder No. 6 injector open circuit	Nozzle disconnected Injector wiring high resistance, short to ground Injector failure	For information on fuel system checks, refer to the appropriate section in the workshop manual. Refer to the guided diagnostic program for this code on the approved diagnostic system.
P210129	Throttle Actuator A Control Motor Circuit Range/Performance Problems	Throttle, gearbox or motor sticking	Check for fuel system DTCs and a message on the instrument panel. Repair if necessary. If problem persists, replace throttle body. Refer to the relevant section in the workshop manual.
P210164	Throttle Actuator A Control Motor Circuit Range/Performance Problems	Throttle, gearbox or motor sticking	Check for fuel system DTCs and a message on the instrument panel. Repair if necessary. If problem persists, replace throttle body. Refer to the relevant section in the workshop manual.
P210329	Throttle Actuator A Control Motor Circuit High Voltage	Throttle actuator control circuit short circuit to battery ECM malfunction	Check the electric throttle body and circuits. Refer to the electrical manual. Clear the DTCs and check for correct operation. Refer to the guided diagnostic program for this code on the approved diagnostic system. If ECM is suspected, refer to the warranty policy and procedures manual.
P210364	Throttle Actuator A Control Motor Circuit High Voltage	Control circuit short circuit to battery ECM malfunction	Check the electric throttle body and circuits. Refer to the electrical manual. Clear the DTCs and check for correct operation. Refer to the guided diagnostic program for this code on the approved diagnostic system. If 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 indicating the cause of the fuel cut. Follow the steps for these DTCs.
P210629	Throttle Motor Control System - Forced Engine Shutdown	Throttle MIL request due to fuel cut	Check for DTCs indicating the cause of the fuel cut. Follow the steps for these DTCs.
P210664	Throttle Actuator Control System - Forced Power Limitation	Intentional limitation of performance (emergency mode "limp home")	Check for fuel system DTCs and a message on the instrument panel. Repair if necessary. If problem persists, replace throttle body. refer to the relevant section in the workshop manual.
P211800	Throttle Actuator Control Motor Operating Range/Current Problems	Throttle Motor Over Current Condition Registered ECM malfunction	Refer to the electrical manual and check the wiring between the ECM and the throttle actuator. Refer to the guided diagnostic program for this code on the approved diagnostic system. If an ECM malfunction is suspected, refer to the Warranty Policy and Procedures Manual.
P211900	Throttle Body Operating Range/Performance Issues in Throttle Actuator Control Aspect	Throttle spring failure	Check the throttle return spring on the throttle body. Repair/replace as needed. Check for fuel system DTCs and a message on the instrument panel. Repair if necessary. If problem persists, replace throttle body. refer to the relevant section in the workshop manual.