Engine Controls - System & Component Testing BMW X5 E53

INTRODUCTION

Before testing separate components or systems, perform procedures in BASIC DIAGNOSTIC PROCEDURES article. Since many computer-controlled and monitored components set a trouble code if they malfunction, also perform procedures in SELF-DIAGNOSTICS article.

Note. System and component testing of BMW engine management system is best accomplished using the BMW MoDIC (hand-held scan tester), BMW Service Tester (Sun 2013 Engine Analyzer) and applicable BMW diagnostic software. Tester permits technician to activate components and monitor status inquiries. Diagnostic Trouble Codes (DTCs) can also be assessed using generic scan tool connected to Data Link Connector. See SELF-DIAGNOSTICS article. Resistance values can be measured directly on component. See WIRING DIAGRAMS article for additional information.

Ground, Power & Input/Output Circuits

Testing information is not available from manufacturer. See WIRING DIAGRAMS article to identify DME/Motronic control unit ground circuits, power circuits and input/output circuits. (Scheme 27)- (Scheme 30). See DME PCM CONTROL UNIT LOCATION table.

Scheme 27

Scheme 28

Scheme 29

Scheme 30

Scheme 31

DME PCM CONTROL UNIT LOCATION

SENSORS

For sensor and switch location, see ENGINE SENSORS & SWITCHES table.

ENGINE SENSORS & SWITCHES

RELAYS

For fuel pump relay, see FUEL DELIVERY under FUEL SYSTEM. For relay locations, see DME & FUEL PUMP RELAY LOCATION table. (Scheme 32)- (Scheme 61).

DME & FUEL PUMP RELAY LOCATION

Scheme 32

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Scheme 53

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Scheme 60

Scheme 61

FUEL DELIVERY

Note. For fuel system pressure testing, see BASIC DIAGNOSTIC PROCEDURES article.

Fuel Pump Relay

Remove fuel pump relay. Apply battery voltage to relay terminals No. 30 and 86. (Scheme 62) Ground relay terminal No. 85. Voltage should now exist at relay terminal No. 87. Replace relay if it does not work as indicated.

Note. If relay does not work on vehicle, check battery feed, DME master (main) relay, DME/Motronic control unit and ground circuits going to fuel pump relay. See WIRING DIAGRAMS article. Only sockets No. 2, 4, 6 and 8 are used by relay.

Fuel Pressure Regulator

As operating mode of engine varies, so does amount of fuel it requires, ranging from low at idle speed to high at full throttle. This requirement is set with the help of pressure regulator. Pressure regulator governs fuel pressure, controlling it between low and high to suit requirements. Fine adjustment of fuel injection quantity is performed using fuel injection period controlled by DME. Vacuum in intake manifold provides load connection for pressure regulation. This vacuum is applied to diaphragm in pressure regulator. At idle speed or when coasting, a vacuum develops in intake pipe. Fuel pressure reduces by this amount, starting from nominal value. Nominal value is embossed in housing of pressure regulator. At full throttle, intake pipe is approximately zero and pressure regulator controls fuel pressure to nominal value embossed on housing.

1. Remove fuel pressure regulator. See «REMOVAL, OVERHAUL & INSTALLATION»(/bmw/x5/e53-1999-2003/remont/removal-installation/#how-to-overhaul-installation-the-engine-controls-removal) article. Note code number and nominal pressure on fuel pressure regulator body. Install BMW Service Tester (133060) with connecting hose (133064) in fuel feed left line.
2. Remove fuel pump relay. See «DME & FUEL PUMP RELAY LOCATION»(/bmw/x5/e53-1999-2003/remont/testing-diagnostics/#engine-controls-system-component-testing) table. Connect jumper wire between relay base terminals No. 30 and 87. Read off fuel injection pressure on pressure gauge.
3. If fuel pressure drops rapidly, seal return line (upper line) with Clamp (133010) and briefly operate fuel pump. If injection pressure in now stable, pressure regulator is defective. If injection pressure drops, check for leak in front of pressure regulator.

Fuel Pressure Check (Lack Of Power)

Run engine at idle and check fuel pressure. See FUEL PRESSURE REGULATOR . Disconnect vacuum hose from fuel pressure regulator, simulating wide open throttle. If fuel pressure does not increase 5.8-10.1 psi (.40-.71 kg/cm 2 ), replace vacuum hose and repeat test. If fuel pressure still does not increase, replace fuel pressure regulator.

Fuel Pressure Check (Hard Start)

1. Run engine at idle then turn off. Note fuel pressure. Note fuel pressure again after 20-30 minutes. If fuel pressure decreases by greater than 7.2 psi (.5 kg/cm 2 ), turn engine on, wait for pressure to stabilize, then turn engine off and immediately clamp off intake line near pressure gauge with Clamp (133010). Note fuel pressure. Read fuel pressure again after 20-30 minutes.
2. If fuel pressure drops by less than 7.2 psi (.5 kg/cm 2 ), check for fault in fuel supply lines, in-tank supply hose, or defective non-return valve in fuel pump. If fuel pressure again drops by more than 7.2 psi (.5 kg/cm cm2 ), replace pressure regulator.

Fuel Pressure & Volume

1. To check fuel pressure, install BMW Service Tester or DIS tester with connecting line and "T"Section (13 3 064) in the fuel delivery line between fuel filter and pressure regulator. Fuel in fuel lines is under 44 psi (3 bar) pressure. Catch and dispose of escaping fuel. See «FUEL PRESSURE & DELIVERY PERFORMANCE»(/bmw/x5/e53-1999-2003/remont/testing-diagnostics/#engine-controls-system-component-testing) table.
2. Disconnect fuel return line. Attach an extension hose. Place hose in Measuring Glass (133020). Remove fuel pump relay. Apply battery voltage to relay base terminals No. 30 and 87. (Scheme 62) See «FUEL PRESSURE & DELIVERY PERFORMANCE»(/bmw/x5/e53-1999-2003/remont/testing-diagnostics/#engine-controls-system-component-testing) table.

FUEL PRESSURE & DELIVERY PERFORMANCE

Scheme 62

Fuel Injector

Individual fuel injector resistance should be 15-17 ohms. Injector group resistance should be 7.5-8.5 ohms for V8 and V12 (each bank) and 5-6 ohms for 6-cylinder engine.

Fuel Injector Leakage

1. Remove fuel injectors. See «FUEL RAIL & INJECTORS»(/bmw/x5/e53-1999-2003/remont/removal-installation/#how-to-overhaul-installation-the-engine-controls-removal) in REMOVAL & INSTALLATION article. Mark sequence of injector valves relative to cylinders on each injector valve. Clip injector valves into Holding Fixture (13 6 205). Connect special tool to injector valves. Connect Harness (13 6 206) to a 12-volt battery. This removes the remaining fuel from the injector valves. Lay a clean cloth under injector valves to catch remaining fuel. Connect holding fixture to compressed air connection at maximum 43 psi (3 bar). Residual fuel is now blown out of the injector valves. CAUTION: Carry out leak test only after remaining fuel has been blown out of injector valves.
2. Separate harness from injector valves. Install injector valves with holding fixture in a container with hot water at 140-176°F (60-80°C). Regulate air pressure at connection No. 1 on holding fixture to 43 psi (3 bar). Note volume of air emerging. Permitted volume of air emerging is 2 air bubbles per injector valve within a 15-second period. Injector valves with larger amounts of air emerging must be cleaned. Remove injector valves from water and dry with compressed air.

Fuel Injector Cleaning

1. Remove fuel injectors. See «FUEL RAIL & INJECTORS»(/bmw/x5/e53-1999-2003/remont/removal-installation/#how-to-overhaul-installation-the-engine-controls-removal) in REMOVAL & INSTALLATION article. Install injector valves in Holding Fixture (13 6 205). (Scheme 63) Connect Harness (13 6 206) to injector valves and to a 12-volt battery. This removes remaining fuel from injector valves. Lay a clean cloth under injector valves to catch remaining fuel. Connect holding fixture to compressed air connection (maximum 44 psi). (Scheme 64) Residual fuel is now blown out of injector valves.
2. Separate Harness (13 6 206) from injector valves. Install injectors with holding fixture in a container with hot water at 140-176°F (60-80°C). (Scheme 65) Regulate air pressure at connection on holding fixture to 44 psi. Note volume of air emerging from injectors. Permitted volume of air emerging from each injector is 2 air bubbles per injector within a 15-minute period. Injectors with a larger amount of air must be cleaned. Remove injectors from water and dry well with compressed air.
3. Use Ultrasonic Cleaning Unit (13 6 200) to clean injector valves. Attach injector valves to cleaning unit with holding fixture. Fill cleaning unit with Cleaning Concentrate (13 6 207). (Scheme 65) Perform cleaning procedure as specified by manufacturer. Perform leak test on cleaned injector valves. See «FUEL INJECTOR LEAKAGE»(/bmw/x5/e53-1999-2003/remont/testing-diagnostics/#engine-controls-system-component-testing__fuel-injector-leakage). CAUTION: Do not carry out leak test in cleaning concentrate but rather in a water bath.
4. To remove preserving agent, rinse new injector valves with fuel only after about 5 minutes. Install injector valves immediately in engine and run engine. This flushes out any remaining cleaning concentrate, preventing injector valve corrosion. Due to the risk of corrosion, cleaned injector valves cannot be stored.

Scheme 63

Scheme 64

Scheme 65

IDLE SPEED CONTROL VALVE

See IDLE SPEED CONTROL VALVE LOCATION table. Idle speed control valve is either a 2-pin or 3-pin type. (Scheme 66)and (Scheme 67).

Scheme 66

Scheme 67

IDLE SPEED CONTROL VALVE LOCATION

IGNITION SYSTEM

Note. For basic ignition checks and oscilloscope pattern diagnosis, see BASIC DIAGNOSTIC PROCEDURES article.

Ignition Coil Resistance

Measure primary coil resistance between terminal No. 1 and terminal No. 15. (Scheme 68) Secondary coil resistance cannot be measured. See IGNITION COIL RESISTANCE table.

Scheme 68

Scheme 69

1. Select cylinder mode on BMW SERVICE TESTER (Sun 2013 Engine Analyzer). Connect universal adapter lead on tester. Connect Brown lead to known good engine ground. (Scheme 69) Connect Black lead to terminal No. 1 on Adapter (127020).
2. Connect adapter to ignition coil of cylinder being tested. Red lead is not used as only one cylinder can be measured. Engine speed displayed will be reduced by a factor of 4. Produce stopped signal on oscilloscope by pressing "R" button on tester. Combustion voltage line will be very erratic on oscilloscope pattern (this is normal).

Ignition Voltage Too High

Check for excessive spark plug electrode gap, high compression, lean air/fuel mixture, low electrode temperature, or burnt spark plug electrode.

Ignition Voltage Too Low

Check for insufficient spark plug electrode gap, low compression, or high electrode temperature.

Ignition Coil Secondary Signal Check

1. Connect engine analyzer and Adapter (127020) as described in «IGNITION COIL PRIMARY SIGNAL CHECK»(/bmw/x5/e53-1999-2003/remont/testing-diagnostics/#engine-controls-system-component-testing). Remove ignition coil. Connect a spark plug wire (between coil and spark plug) to cylinder being tested. Connect inductive pickup Blue lead, on lead to cylinder being tested. (Scheme 70) IGNITION COIL RESISTANCE - Ohms @ 68°F (20°C) Primary Secondary.8 (1) Not Measurable (1) Specification is approximate.
2. Produce stopped signal on oscilloscope by pressing "R" button on tester. Display of ignition signal on oscilloscope will be strongest when inductive clip and Black lead are connected to same cylinder. Display on oscilloscope may be disturbed by neighboring ignition leads (this is normal).

Scheme 70

DISTRIBUTOR IGNITION SYSTEM (V12)

Perform resistance measurement on individual components. See DISTRIBUTOR SPECIFICATIONS table. Check distributor rotor and distributor cap for hairline cracks and traces of scorching. If any are present, establish the cause and replace corresponding component.

DISTRIBUTOR SPECIFICATIONS

Fuel Tank Vent (Evaporation) Control Valve

See FUEL EVAPORATION CONTROL VALVE LOCATION table.

FUEL EVAPORATION CONTROL VALVE LOCATION

FUEL TANK LEAKAGE

Note. If a leak in the tank ventilation system is indicated by CHECK ENGINE light in instrument cluster lighting up, a leak test must be carried out. Fault memory of DME control unit must be read out using BMW or generic scan tool. If sensors are okay, then begin leak test. Ensure following conditions are observed to obtain plausible measuring results: Contents of fuel tank: 25-75% full. Park vehicle at least 2 hours before test so fuel temperature is approximately that of ambient temperature. Ideal fuel temperature is approximately 50-68°F (10-20°C). Never refuel vehicle directly prior to leak test due to strong emission of gas by fresh fuel.

3-Series (E46)

1. Remove screws and panel. Remove expansion rivet and panel. (Scheme 71) Unlock line and detach line from dust filter. (Scheme 72) Seal dust filter with special tool. Remove tank filler cap and connect Special Tool (16 1 150) to tank filler neck. (Scheme 73) Screw in rear towing eye and hook Special Tool (16 1 150) into it. Connect special tool to workshop compressed air system of 116-145 psi (8-10 bar) with compressed air hose. (Scheme 74) Connect pressure sensor with measuring range of 0-51 psi (0-3.5 bar). NOTE: Ensure pressure regulator on Special Tool (16 1 150) is set completely in "-" direction and non-return cock between pressure regulator and pressure sensor is closed. Select "Measuring Technology" function on Diagnosis Information System (DIS).
2. Set measuring range in accordance with pressure sensor to 0-51 psi (0-3.5 bar). Open non-return cock on Special Tool (16 1 150) and increase pressure in tank system by.72 psi (.050 bar) with the pressure regulator. WARNING: Do not increase pressure by more than 1.45 psi (100 bar), as damage to fuel tank and tank ventilation system is possible.
3. Close non-return cock. Wait about 20 seconds for system to settle. Read off pressure value, then wait 60 seconds. Read off final pressure value and compare with starting pressure value. If pressure drop within range of.116-1.7 psi (.008-.12 bar), measurement must be repeated to obtain a confirming result. If pressure drop in 60 seconds is greater than.145 psi (.010 bar), system is leaking.
4. Leak test can be carried out with a leak detector. Possible causes may be fuel filler cap leaking, tank ventilation line leaking (fuel tank-activated carbon canister-tank ventilation valve), tank ventilation valve leaking (engine compartment), tank sensor on fuel tank leaking or activated carbon canister non-return valve leaking (spare wheel recess).

Scheme 71

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Scheme 73

Scheme 74

5-Series (E39) 6-Cylinder

1. Remove luggage compartment mat and spare tire. Remove battery cover. Remove hexagon nut and plastic nut. (Scheme 75) Remove cover of activated carbon canister upward.
2. Disconnect electrical connector of activated carbon canister non-return valve. (Scheme 76) Connect Special Tool (12 6 410/411) to activated carbon canister non-return valve and vehicle battery. (Scheme 77) Activated carbon canister non-return valve is closed by applying 12 volts. Ensure voltage is sufficient and do not reverse terminals. Remove tank filler cap and connect special tool (16 1 150) to tank filler neck. (Scheme 73)
3. Screw in rear towing eye and hook Special Tool (16 1 150) into it. Connect special tool to compressed air system of 116-145 psi (8-10 bar) with compressed air hose. (Scheme 74) Connect pressure sensor with measuring range of 0-51 psi (0-3.5 bar). WARNING: Ensure pressure regulator on Special Tool (16 1 150) is set completely in "-" direction and non-return cock between the pressure regulator and pressure sensor is closed.
4. Select "Measuring Technology" function on Diagnosis Information System (DIS). Set measuring range in accordance with pressure sensor to 0-51 psi (0-3.5 bar). Open non-return cock on Special Tool (16 1 150) and increase pressure in tank system by.72 psi (.050 bar) with pressure regulator. WARNING: Do not increase pressure by more than 1.45 psi (.100 bar), as damage to fuel tank and tank ventilation system is possible.
5. Close non-return cock. Wait for about 20 seconds for system to settle. Read off pressure value, then wait 60 seconds. Read off final pressure value and compare with starting pressure value. If pressure drop is in area between.116-1.7 psi (.008-.012 bar), measurement must be repeated to obtain a confirming measurement. If pressure drop in 60 seconds is greater than.145 psi (.010 bar), system is leaking.
6. Leak test can be carried out with a leak detector. Possible causes may be fuel filler cap, tank ventilation line (fuel tank-activated carbon canister-tank ventilation valve), tank ventilation valve (engine compartment), tank sensor on fuel tank or activated carbon canister non-return valve (spare tire recess).

Scheme 75

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Scheme 77

5-Series (E39) V8 (Except M5) & 7-Series (E38) V8 & V12

1. Remove left rear wheel. Remove left rear wheel housing trim. Remove leak diagnosis pump air cleaner from retaining bracket of activated carbon filter from below. (Scheme 78) Using hose clamp, seal with Special Tool (16 1 161).
2. Remove tank filler cap and connect Special Tool (16 1 150) to tank filler neck. (Scheme 73) Screw in rear towing eye and hook Special Tool (16 1 150) into it. Connect special tool to compressed air system of 116-145 psi (8-10 bar) with compressed air hose. Connect pressure sensor with measuring range of 0-51 psi (0-3.5 bar). (Scheme 74) WARNING: Ensure pressure regulator on Special Tool (16 1 150) is set completely in "-" direction and nonreturn cock between pressure regulator and pressure sensor is closed.
3. Select "Measuring Technology" function on Diagnosis and Information System (DIS). Set measuring range in accordance with pressure sensor to 0-51 psi (0-3.5 bar). Open non-return cock on Special Tool (16 1 150) and increase pressure in tank system by.72 psi (.050 bar) with pressure regulator. WARNING: Do not increase pressure by more than 1.45 psi (.100 bar), as damage to fuel tank and tank ventilation system is possible.
4. Close non-return cock. Wait for about 20 seconds for system to settle, read off pressure value, then wait for 60 seconds. Read off final pressure value and compare with starting pressure value. If pressure drop is.116-1.7 psi (.008-.12 bar), measurement must be repeated to obtain a confirming result. If pressure drop in 60 seconds is greater than.145 psi (.010 bar), system is leaking.
5. Leak test can be carried out with a leak detector. Possible causes may be fuel filler cap leaking, tank ventilation line leaking (fuel tank-activated carbon canister-tank ventilation valve), tank ventilation valve leaking (engine compartment), tank sensor on fuel tank leaking or activated carbon canister non-return valve leaking (spare wheel recess).

Scheme 78

See also:
• BASIC DIAGNOSTIC PROCEDURES
• WIRING DIAGRAMS
• REMOVAL, OVERHAUL & INSTALLATION
• DME PCM CONTROL UNIT LOCATION
• FUEL DELIVERY
• FUEL PRESSURE REGULATOR
• FUEL INJECTOR LEAKAGE