Diagnostics and testing 4.4L (Discovery 3)

Inspection and verification

1. Ensure that the customer's complaint is justified.

2. Visually inspect for obvious mechanical and electrical problems.

Mechanical factors	Electrical factors
Engine oil level Coolant level Fuel level Fuel contamination/fuel brand/fuel quality Exhaust Gas Recirculation (EGR) Valves	Fuses and fuses Wiring harness Loose or corroded electrical connectors Ignition coils Sensor(s) Engine Control Module (ECM) Transmission Control Module (TCM)

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 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

Symptom of malfunction (general)	Sign of malfunction (specific)	Possible reasons	Actions
No launch	The engine turns over 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. For ignition system checks, refer to the ignition coil malfunction DTCs in this Index. Check the fuel system. Check the Cr sensor circuits. Refer to the appropriate section of the service manual. If in doubt about the module, refer to the warranty policy and procedures manual.
No launch	The engine turns over and flashes but does not start.	Fuel Evaporative Canister Purge Valve Fuel system Spark plugs Ignition coil failure Wiring harness	Check the evaporative emission purge valve. Check the fuel system. Refer to the appropriate section of the workshop manual. Check the spark plug condition and gaps. For ignition coil testing information, refer to the ignition coil malfunction DTCs in this Index.
Difficulty starting	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 the injectors and fuel system. Check the fuel temperature, IAT, and MAF sensor circuits. Check the evaporative emission purge valve. Refer to the appropriate section of the service manual. For ignition coil testing information, refer to the ignition coil malfunction DTCs in this Index.
Difficulty starting	Difficulty starting after hot soak (the car is kept 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 the injectors and fuel system. Check the fuel temperature, IAT, and MAF sensor circuits. Check the EVAP purge valve. For ignition coil testing information, refer to the ignition coil malfunction DTCs in this Index. Refer to the appropriate section of the service manual.
The engine stalls	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. Check the MAF sensor circuits. For ignition coil testing information, refer to the ignition coil malfunction DTCs in this Index. For intake system information. Check the fuel lines for leaks/damage. Refer to the appropriate section of the service manual.
Poor overall vehicle handling	Engine lag/poor acceleration	Fuel pump module Fuel lines Leak in the injector Fuel pressure Air leak TP sensors Throttle body motor Ignition system EGR valve sticking HO2 sensors Gearbox failure Difficulty moving the pedal (floor covering, etc.) Accelerator Pedal Position Sensor (APP)	Check the fuel pump module operation. Check the fuel lines for leaks/damage. Check the injectors. Check the air intake system for leaks. Check the TP sensor and throttle motor circuits. For ignition coil testing information, refer to the ignition coil malfunction DTCs in this Index. Check the EGR valves. Check for HO2 sensor related DTCs. For transmission information, check the accelerator pedal travel. Check the APP sensor circuits. Refer to the appropriate section of the service manual.
Poor overall vehicle handling	Backfires in the engine	Fuel pump module Fuel lines Air leak MAF sensor HO2 sensors Ignition system Variable Valve Timing (VCT) Hub Seizure APP sensor	Check the operation of the fuel pump module. Check the fuel lines for leaks/damage. Check the air intake system for leaks. Check the MAF sensor circuits. Check for HO2 sensor related DTCs. For ignition coil testing information, refer to the ignition coil related DTCs in this Index. Check the VCT and APP sensor circuits. Refer to the appropriate section of the service manual.
Poor overall vehicle handling	Engine jerks	Fuel pump module Fuel lines MAF sensor Wiring harness TP sensors Throttle body motor Ignition system	Check the fuel pump module operation. Check the fuel lines for leaks/damage. Check the MAF, TP and throttle motor circuits, refer to the electrical manual. For ignition coil testing information, refer to the ignition coil malfunction DTCs in this Index.

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 codes	Description	Possible reasons	Actions
P030000	Random misfire/misfire series detected	Malfunctions in the low voltage electrical circuit from the ECM to the ignition coil (also registered DTC codes of misfires in cylinders) Ignition coil failure Malfunction/ contamination/ incorrect spark plug gap Fuel supply pressure (low/high) Fuel injector electrical circuit fault(s) (injector DTC codes are also logged) Reduced flow/leak in fuel injectors Fuel injectors are constantly open Fuel contamination Low compression in the engine cylinder Worn camshaft/broken valve springs Adjusting valve clearances	For ignition coil testing information, refer to the ignition coil malfunction DTCs in this Index. Check the spark plug condition and gaps. Check the fuel pressure and injector DTCs, refer to the appropriate section in the workshop manual.
P030100	Misfire detected in cylinder #1	Refer to P030000 for possible causes.	For ignition coil checks, refer to the ETALQ guided diagnostic routine for this code on the approved diagnostic system. Check the spark plug condition and gap. Check for fuel pressure and injector DTCs, refer to the relevant section in the workshop manual.
P030200	Misfire detected in cylinder #2	Refer to P030000 for possible causes.	For ignition coil checks, refer to the ETALL guided diagnostic routine for this code on the approved diagnostic system. Check the spark plug condition and gap. Check fuel pressure and injector DTCs, refer to the relevant section in the workshop manual.
P030300	Misfire detected in cylinder #3	Refer to P030000 for possible causes.	For ignition coil checks, refer to the ETALR guided diagnostic program for this code on the approved diagnostic system. Check the spark plug condition and gap. Check for fuel pressure and injector DTCs, refer to the relevant section in the workshop manual.
P030400	Misfire detected in cylinder #4	Refer to P030000 for possible causes.	For ignition coil checks, refer to the ETALU guided diagnostic program for this code on the approved diagnostic system. Check the spark plug condition and gap. Check the fuel pressure and injector DTCs, refer to the relevant section in the workshop manual.
P030500	Misfire detected in cylinder #5	Refer to P030000 for possible causes.	For ignition coil checks, refer to the ETALS guided diagnostic program for this code on the approved diagnostic system. Check the spark plug condition and gap. Check for fuel pressure and injector DTCs, refer to the relevant section in the workshop manual.
P030600	Misfire detected in cylinder #6	Refer to P030000 for possible causes.	For ignition coil checks, refer to the ETALV guided diagnostic program for this code on the approved diagnostic system. Check the spark plug condition and gap. Check fuel pressure and injector DTCs, refer to the relevant section in the workshop manual.
P030700	Misfire detected in cylinder #7	Refer to P030000 for possible causes.	For ignition coil checks, refer to the ETAME guided diagnostic program for this code on the approved diagnostic system. Check the spark plug condition and gap. Check for fuel pressure and injector DTCs, refer to the relevant section in the workshop manual.
P030800	Misfire detected in cylinder #8	Refer to P030000 for possible causes.	For ignition coil checks, refer to the ETAMF guided diagnostic program for this code on the approved diagnostic system. Check the spark plug condition and gap. Check the fuel pressure and injector DTCs, refer to the relevant section in the workshop manual.
P031600	Misfire on start-up (detected in the first 1000 rpm)	Misfire detected in first 1000 rpm Refer to P030000 for possible causes.	Perform the tests specified for a normal misfire code, but on a cold engine.
P035100	Cylinder 1 Ignition Coil Primary/Secondary Circuit	ECM to Ignition Module/Coil Wake-up Circuit High Resistance, Short to Ground Ignition Coil Module/Ground Circuit High Resistance Ignition Coil/Module Power Circuit High Resistance (including relay, if available)	Refer to the electrical manual and check the ignition coil circuit. Ignition system tests are described in the appropriate section of the workshop manual. Refer to the ETALQ guided diagnostic program for this code on the approved diagnostic system.
P035200	Cylinder 2 Ignition Coil Primary/Secondary Circuit	ECM to Ignition Module/Coil Wake-up Circuit High Resistance, Short to Ground Ignition Coil Module/Ground Circuit High Resistance Ignition Coil/Module Power Circuit High Resistance (including relay, if available)	Refer to the electrical manual and check the ignition coil circuit. Ignition system tests are described in the appropriate section of the workshop manual. Refer to the ETALT guided diagnostic program for this code on the approved diagnostic system.
P035300	Cylinder 3 Ignition Coil Primary/Secondary Circuit	ECM to Ignition Module/Coil Wake-up Circuit High Resistance, Short to Ground Ignition Coil Module/Ground Circuit High Resistance Ignition Coil/Module Power Circuit High Resistance (including relay, if available)	Refer to the electrical manual and check the ignition coil circuit. Ignition system tests are described in the appropriate section of the workshop manual. Refer to the ETALR guided diagnostic program for this code on the approved diagnostic system.
P035400	Cylinder 4 Ignition Coil Primary/Secondary Circuit	ECM to Ignition Module/Coil Wake-up Circuit High Resistance, Short to Ground Ignition Coil Module/Ground Circuit High Resistance Ignition Coil/Module Power Circuit High Resistance (including relay, if available)	Refer to the electrical manual and check the ignition coil circuit. Ignition system tests are described in the relevant section of the workshop manual. Refer to the ETALU guided diagnostic program for this code on the approved diagnostic system.
P035500	Cylinder 5 Ignition Coil Primary/Secondary Circuit	ECM to Ignition Module/Coil Wake-up Circuit High Resistance, Short to Ground Ignition Coil Module/Ground Circuit High Resistance Ignition Coil/Module Power Circuit High Resistance (including relay, if available)	Refer to the electrical manual and check the ignition coil circuit. Ignition system tests are described in the appropriate section of the workshop manual. Refer to the ETALS guided diagnostic program for this code on the approved diagnostic system.
P035600	Cylinder 6 Ignition Coil Primary/Secondary Circuit	ECM to Ignition Module/Coil Wake-up Circuit High Resistance, Short to Ground Ignition Coil Module/Ground Circuit High Resistance Ignition Coil/Module Power Circuit High Resistance (including relay, if available)	Refer to the electrical manual and check the ignition coil circuit. Ignition system tests are described in the appropriate section of the workshop manual. Refer to the ETALV guided diagnostic program for this code on the approved diagnostic system.
P035700	Cylinder 7 Ignition Coil Primary/Secondary Circuit	ECM to Ignition Module/Coil Wake-up Circuit High Resistance, Short to Ground Ignition Coil Module/Ground Circuit High Resistance Ignition Coil/Module Power Circuit High Resistance (including relay, if available)	Refer to the electrical manual and check the ignition coil circuit. Ignition system tests are described in the relevant section of the workshop manual. Refer to the ETAME guided diagnostic program for this code on the approved diagnostic system.
P035800	Cylinder 8 Ignition Coil Primary/Secondary Circuit	ECM to Ignition Module/Coil Wake-up Circuit High Resistance, Short to Ground Ignition Coil Module/Ground Circuit High Resistance Ignition Coil/Module Power Circuit High Resistance (including relay, if available)	Refer to the electrical manual and check the ignition coil circuit. Ignition system tests are described in the relevant section of the workshop manual. Refer to the ETAMF guided diagnostic program for this code on the approved diagnostic system.
P131500	Persistent misfire	Malfunction in the low voltage circuit from the ECM to the ignition coil (also a cylinder misfire DTC is registered) Ignition coil failure Malfunction/ contamination/ incorrect spark plug gap Low fuel pressure Fuel injector electrical circuit fault(s) (injector DTC codes are also logged) Low compression in the engine cylinder	For ignition coil testing information, refer to the ignition coil malfunction DTCs in this Index. Check the spark plug condition and gaps. Check the fuel pressure and injector DTCs, refer to the appropriate section in the workshop manual.
P136700	Additional code for ignition system	Ignition Coil Bank A Monitor Circuit to ECM High Resistance, Short to Ground, Short to Battery Ignition Coil Module Ground Circuit Malfunction, Right Bank	Refer to the electrical manual and check the electrical circuit between the ignition coils and the ECM. Repair as necessary. For ignition coil testing information, refer to the ignition coil malfunction DTCs in this Index.
P136800	Additional code for ignition system	Ignition Coil Bank B Monitor Circuit to ECM High Resistance, Short to Ground, Short to Battery Ignition Coil Module/Ground Circuit Malfunction, Left Bank	Refer to the electrical manual and check the electrical circuit between the ignition coils and the ECM. Repair as necessary. For ignition coil testing information, refer to the ignition coil malfunction DTCs in this Index.