Diagnostics and testing 4.4L (Discovery 3)

Inspection and verification

1. Accurately define the problem stated by the customer.

2. Visually inspect for obvious mechanical and electrical faults.

Mechanical elements	Electrical elements
Fuel leaks Damaged fuel lines Damaged fittings Fuel level Fuel contamination/fuel brand/fuel quality Throttle body Damaged fuel 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 fault identified or described by the customer is found, correct it before proceeding to further actions. (if possible).

[The article was taken from this resource: LRman.ru]

4. Before referring to the symptom chart or DTC index, read all diagnostic trouble codes (DTCs) using an approved diagnostic system or scan tool.

Clear all DTCs after troubleshooting.

Table of signs of malfunctions

Sign of malfunction	Possible reasons	Action taken
The engine cranks but does not start.	Low fuel level/contamination Ignition system Fuel system Crankshaft Position Sensor (CKP) Wiring harness ECM failure	Check the fuel level and condition. Ignition system checks are described in the relevant section of the service station manual. Check for DTC codes associated with the injectors. For testing CKP and wiring harness. Refer to the corresponding section in the service station manual. If you have any doubts about the functionality of the module, please refer to the manual on warranty service policies and procedures.
The engine crankshaft turns, flashes occur, but the engine does not start	Fuel Evaporative Canister Purge Valve Fuel system Spark plugs Ignition coil fault(s)	Purge valve tests are described in the appropriate section of the workshop manual. Check for injector-related DTCs. Ignition system tests are described in the appropriate section of the workshop manual.
Difficulty starting at cold start	Check the antifreeze content in the cooling system Battery Crankshaft Position Sensor (CKP) Exhaust Gas Recirculation (EGR) valve stuck open Fuel system Fuel Evaporative Canister Purge Valve	Battery information is provided in the appropriate section of the workshop manual. Crankshaft position sensor tests are described in the appropriate section of the workshop manual. Check for injector-related DTCs. Purge valve tests are described in the appropriate section of the workshop manual.
Difficulty with hot start	Leak in the injector Fuel system Fuel temperature sensor Intake Air Temperature (IAT) Sensor Mass Air Flow (MAF) Sensor Fuel Evaporative Canister Purge Valve Ignition system	Check for injector-related DTCs. Fuel temperature, air intake temperature, and mass air flow sensor tests are described in the appropriate section of the workshop manual. Purge valve and ignition system tests are described in the appropriate section of the workshop 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 Canister Purge Valve Ignition system	Check for injector-related DTCs. Fuel temperature, air intake temperature, and mass air flow sensor tests are described in the appropriate section of the workshop manual. Purge valve and ignition system tests are described in the appropriate section of the workshop manual.
Engine stalls shortly after starting	Disconnection/reduction of ventilation system capacity ECM relay MAF sensor Ignition system Clogged air filter Air leak Fuel lines	Check the engine ventilation system. Check the operation of the ECM relay. For MAF, fuel rail pressure, and ignition system checks, see the appropriate section of the service manual. For air intake duct and fuel line information, see the appropriate section of 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 EGR valve sticking HO2 sensors Gearbox failure Difficulty moving the pedal (floor covering, etc.)	For information on the fuel pump and fuel line, refer to the corresponding section of the Service station manual. Check for DTC codes associated with the injectors. Checks of the air intake system, throttle position sensors, and accelerator pedal position are described in the corresponding section of the service station manual. For information on checking the throttle motor, refer to the directional diagnostic program in an approved diagnostic system. Ignition system checks are described in the relevant section of the service station manual. Check for DTC codes for HO2 sensors, refer to the DTC Code Index. Refer to the corresponding section of the service station manual for transmission information. Check the accelerator pedal movement.
Backfires in the engine	Fuel pump Fuel lines Air leak MAF sensor APP sensor HO2 sensors Ignition system	For information on the fuel pump, fuel line, and air intake system, refer to the relevant section of the Service station manual. Checks of the mass flow sensors and accelerator pedal position are described in the corresponding section of the service station manual. Check for DTC codes for HO2 sensors, refer to the DTC Code Index. Ignition system checks are described in the relevant section of the service station manual.
Engine jerks	Fuel pump Fuel lines MAF sensor Wiring harness TP sensors Throttle body motor Ignition system	For information on the fuel pump and fuel line, refer to the corresponding section of the Service station manual. Check the mass flow rate and throttle position sensors are described in the corresponding section of the service station manual. For information on checking the throttle motor, refer to the directional diagnostic program in an approved diagnostic system. Ignition system checks are described in the relevant section of the service station manual.
Detonation/knocking in the engine	Fuel pump Fuel lines Fuel quality Knock Sensor (KS)/Electrical Circuit Malfunction MAF sensor HO2 sensors Air leak BARO sensor malfunction (internal ECM failure)	For information on the fuel pump and fuel line, refer to the corresponding section of the Service station manual. Checks of fuel manifold pressure sensors, mass air flow, and detonation are described in the relevant section of the service station manual. Check for DTC codes for HO2 sensors, refer to the DTC Code Index. For information on the air intake system, refer to the relevant section of the service station manual. If you have any doubts about the functionality of the module, please refer to the manual on warranty service policies and procedures.
Lack of throttle response	APP sensor failure TP sensors Throttle body motor	The accelerator pedal position sensor and throttle position sensor tests are described in the relevant section of 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	Checks of the accelerator pedal position sensors, throttle position sensors, coolant temperature sensors, and mass air flow sensors are described in the corresponding section of the service station manual. Refer to the corresponding section of the service station manual for transmission information. For information on checking the air intake system, refer to the relevant section of the service station manual. For information on checking the breather system, see the relevant section of the service station manual.

DTC indicator

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

DTC	Description	Possible reasons	Action taken
P008700	Fuel rail/system pressure too low	Fuel Rail Pressure (FRP) Sensor Disconnected FRP Sensor to ECM Signal Circuit Short to Ground FRP Sensor Power Circuit: High Resistance FRP sensor failure Leak in the fuel line Reducing the fuel line capacity Fuel Pump Module Circuit High Resistance Fuel Pump Module Circuit Short to Ground Fuel pump module malfunction	Fuel rail pressure sensor checks are described in the relevant section of the service station manual. Check fuel lines, fuel pressure, fuel pump module electrical circuits.
P008800	Fuel rail/system pressure too high	Wiring between fuel rail pressure (FRP) sensor and ECM (power/signal): short circuit between circuits Signal circuit between FRP sensor and ECM: short circuit to battery + FRP sensor failure Fuel Pressure Control Valve (FPCV) Malfunction Fuel Pump Module Electrical Circuit: Short to Battery Positive Fuel pump module malfunction	Fuel rail pressure sensor checks are described in the relevant section of the service station manual. Check fuel lines, fuel pressure, fuel pump module electrical circuits.
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 Reducing fuel injector flow Leak in the exhaust system (before the catalytic converter) Fuel vapor recovery 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 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 warming up for a sufficiently long time) MAF sensor malfunction Fuel vapor recovery 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 evaporative emission 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 Reducing fuel injector flow Leak in the exhaust system (before the catalytic converter) Fuel vapor recovery 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 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 warming up for a sufficiently long time) MAF sensor malfunction Fuel vapor recovery 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 evaporative emission system.
P020100	Open circuit of injector cylinder 1	The injector is disconnected Injector Wiring Harness: High Resistance, Short to Ground Injector malfunction	Fuel system checks are described in the appropriate section of the service manual. For this code, refer to the diagnostic procedure supplied with the approved diagnostic system.
P020200	Open circuit of injector cylinder 2	The injector is disconnected Injector Wiring Harness: High Resistance, Short to Ground Injector malfunction	Fuel system checks are described in the appropriate section of the service manual. For this code, refer to the diagnostic procedure supplied with the approved diagnostic system.
P020300	Open circuit of injector cylinder 3	The injector is disconnected Injector Wiring Harness: High Resistance, Short to Ground Injector malfunction	Fuel system checks are described in the appropriate section of the service manual. For this code, refer to the diagnostic procedure supplied with the approved diagnostic system.
P020400	Open circuit of injector cylinder 4	The injector is disconnected Injector Wiring Harness: High Resistance, Short to Ground Injector malfunction	Fuel system checks are described in the appropriate section of the service manual. For this code, refer to the diagnostic procedure supplied with the approved diagnostic system.
P020500	Open circuit of injector cylinder 5	The injector is disconnected Injector Wiring Harness: High Resistance, Short to Ground Injector malfunction	Fuel system checks are described in the appropriate section of the service manual. For this code, refer to the diagnostic procedure supplied with the approved diagnostic system.
P020600	Open circuit of injector cylinder 6	The injector is disconnected Injector Wiring Harness: High Resistance, Short to Ground Injector malfunction	Fuel system checks are described in the appropriate section of the service manual. For this code, refer to the diagnostic procedure supplied with the approved diagnostic system.
P020700	Open circuit of injector cylinder 7	The injector is disconnected Injector Wiring Harness: High Resistance, Short to Ground Injector malfunction	Fuel system checks are described in the appropriate section of the service manual. For this code, refer to the diagnostic procedure supplied with the approved diagnostic system.
P020800	Open circuit of injector cylinder 8	The injector is disconnected Injector Wiring Harness: High Resistance, Short to Ground Injector malfunction	Fuel system checks are described in the appropriate section of the service manual. For this code, refer to the diagnostic procedure supplied with the approved diagnostic system.
P210129	Problems with the operating range/ characteristics of the electric circuit of the electric motor controlling the throttle actuator A	Pinched throttle valve, gearbox or electric motor	Check for fuel supply-related DTC codes and dashboard messages. Repair it if necessary. If the problem persists, replace the throttle body. Refer to the corresponding section in the service station manual.
P210164	Problems with the operating range/ characteristics of the electric circuit of the electric motor controlling the throttle actuator A	Pinched throttle valve, gearbox or electric motor	Check for fuel supply-related DTC codes and dashboard messages. Repair it if necessary. If the problem persists, replace the throttle body. Refer to the corresponding section in the service station manual.
P210329	High voltage in the electrical circuit of the electric motor controlling the throttle actuator A	Electrical control circuit of the throttle actuator: short circuit on the battery side. ECM failure	Check the electrical portion of the throttle assembly and circuits. Refer to the electrical manuals. Clear the DTCs and verify proper operation. For this code, refer to the diagnostic procedure provided with 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 electrical portion of the throttle assembly and circuits. Refer to the electrical manuals. Clear the DTCs and verify proper operation. For this code, refer to the diagnostic procedure provided with the approved diagnostic system. If the ECM is suspected, refer to the warranty policy and procedures manual.
P210500	Electric Throttle Motor Control System - Forced Engine Shutdown	Throttle valve request to turn on MIL due to fuel cut	Check for DTCs that indicate the cause of the fuel cutoff. Perform the actions specified for those DTCs.
P210629	Throttle actuator control system - forced engine power limitation	Intentional reduction of power (emergency operation mode)	Check for fuel supply-related DTC codes and dashboard messages. Repair it if necessary. If the problem persists, replace the throttle body. Refer to the corresponding section in the service station manual.
P210664	Throttle actuator control system - forced engine power limitation	Intentional reduction of power (emergency operation mode)	Check for fuel supply-related DTC codes and dashboard messages. Repair it if necessary. If the problem persists, replace the throttle body. Refer to the corresponding section in the service station 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. For this code, refer to the diagnostic procedure provided with the approved diagnostic system. If a faulty ECM 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 necessary. Check for fuel system related DTC codes and dashboard message. Repair if necessary. If problem persists, replace throttle body. Refer to the appropriate section in the service station manual.