Engine Controls - System & Component Testing BMW Z4 E85/E86

INTRODUCTION

Note. BMW troubleshooting charts, guides and aids for diagnosis are integrated into BMW-specific service tools. BMW does not have or supply stand-alone guides for testing or troubleshooting. All OBD-II equipped BMWs are designed to be programmed and coded electronically. Diagnosis, coding, and programming on any OBD-II BMW may be carried out with BMW's DISplus, Group Tester 1 (GT1) or similar scan tool.

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 - EXCEPT 7-SERIES or SELF DIAGNOSTICS - 7-SERIES article.

Note. BMW diagnostic hardware, such as DISplus/GT1 as well as a reputable hand held multimeter should be used when testing inputs and components. Slack Tube Manometer Test Tool (99 00 0 001 410) should be used to troubleshoot crankcase ventilation valves. It is best to make the checks at the ECM connection, as this method includes testing the wiring harness. The correct universal adapter for engine and model being tested should be used. This will ensure the pin connectors and the harness will not be damaged. When installing the universal adapter to the ECM (located in the electronics box in the engine compartment), make sure the ignition is switched off. On Siemens MS45, allow at least 3 minutes to elapse after the key was set to OFF position before disconnecting ECM/TCM. This will allow sufficient time to complete the DM TL test. Voltage may be present (up to 3 minutes) causing damage to the ECM/TCM if they are disconnected during this time period.

DIGITAL MOTOR ELECTRONICS (DME) CONTROL UNIT

Note. Digital Motor Electronics (DME) control unit may also be referred to as Electronic Control Module (ECM).

Ground, Power & Input/Output Circuits

See PIN VOLTAGE CHARTS article to identify DME control unit ground circuits, power circuits and input/output circuits. To identify DME/ECM connector terminals (Scheme 29)- (Scheme 32). See DME CONTROL UNIT LOCATION table.

Scheme 29

Scheme 30

Scheme 31

Scheme 32

Scheme 33

DME CONTROL UNIT LOCATION

SENSORS

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

ENGINE SENSORS & SWITCHES

Scheme 34

COOLANT TEMPERATURE SENSOR

Coolant temperature sensor decreases in resistance as temperature rises and vice versa. ECM monitors the sensor voltage which varies as temperature changes the resistance value. As temperature rises, resistance through the sensor decreases, voltage drop of the sensor decreases, and input signal voltage also decreases (5-0 volts). Sensor should be tested using DISplus/GT1 multimeter. DISplus/GT1 multimeter ECM input should be 2.250 k/ohms at 68°F (20°C). Gauge input should be 6.7 k/ohms at 68°F (20°C).

CRANKSHAFT POSITION SENSOR

Crankshaft position/RPM sensor should be tested using DISplus/GT1 for power supply, DC voltage, status display, oscilloscope display found under preset measurements, and engine speed sensor signal.

7-Series

1. Evaporative leakage detection is performed on fuel storage system by Tank Leakage Diagnostic Module (DM-TL) pump which contains an integral DC motor that is activated by ECM. ECM monitors pump motor operating current as the measurement for detecting leaks. DM-TL generates a pressure of.29-.43 psi (20-30 mbar) in the fuel tank and evaporative system. Electrical current required for this is calculated by ECM and serves as the indirect value for the tank pressure. The DM-TL carries out a reference measurement before each measurement. This is performed by building up a pressure for 10-15 seconds using an internal orifice of.019" (.5 mm) as a reference and ECM monitors current (20-30 mA) required by pump motor.
2. If a lower pressure is detected in pressure build-up (low current draw) as compared to reference measurement, this indicates a leak in fuel tank/evaporative system. If a higher pressure is detected (higher current draw), the system does not have a leak. The pump also contains an ECM controlled change over valve that is energized closed during a leak diagnosis test. The ECM only initiates a leak diagnosis test every second time the criteria is met. The criteria is as follows: Engine off with ignition off. ECM still in active state or what is known as "follow up mode". (ECM relay energized, ECM and components online for extended period after key off). Prior to engine/ignition switch off condition, vehicle must have been driven for a minimum of 20 minutes. Prior to minimum 20 minute drive, vehicle must have been off a minimum of 5 hours. No faults in ECM for DM-TL/tank venting system. Fuel tank capacity must be between 10-90 percent (safe approximation between 1/4-3/4 of a tank). Ambient air temperature between 19-95°F (-7-35°C). Altitude less than 8202 feet. Battery voltage between 11.5-14.5 volts.
3. When these criteria are satisfied every second time, ECM will start FUEL SYSTEM LEAK DIAGNOSIS TEST. Test will typically be carried out once a day. The following morning, the test will run again.

X5 (6-Cylinder) & E46

The MS42.0 system uses Bosch LSH 25 oxygen sensors. Voltage range is between 0-800 mV.

Z4 & M3

Vehicles use Bosch LSH 25 oxygen sensors, The pre-cat oxygen sensors measure residual oxygen content of exhaust gas. The sensors produce a low voltage (0-1000 mV) proportional to the oxygen content that allows the ECM to monitor the air/fuel ratio.

7-Series (V8)

1. Sensor conductivity is efficient when the oxygen sensor is hot 1382°F (750°C). For this reason, sensor contains a heating element. This reduces warm up time and retains heat during low engine speed when exhaust temperature is cooler. Oxygen sensor heating elements receive power from Integrated Voltage Supply Module (IVM) and ground supply is pulse width modulated by the ECM. Monitored voltage signal is constantly changing due to combustion variations and normal exhaust pulsations. At a value of lambda = 1, pump cell requires approximately 3 milliamps. Oxygen sensor signal voltage is approximately 1.5 volts. Reference cell voltage is approximately 450 millivolts. At a lambda value of less than one (rich), oxygen sensor signal voltage is approximately.3 volt. At a lambda value of greater than one (lean), oxygen sensor signal voltage is approximately 4.3 volts.
2. If necessary, ECM will correct air/fuel ratio by regulating injection time. ECM monitors length of time sensors are operating in lean, rich and rest conditions. Evaluation period of sensors is over a predefined number of oscillation cycles and pump cell amperage.

7-Series (V12)

Bosch LSH 25 oxygen sensors produce a low voltage (0-1000 mV) proportional to the oxygen content exiting the catalytic converters. If exhaust has a lower oxygen content (rich mixture), there will be a large ion migration through the sensor, generating a higher voltage (950 mV). If the exhaust has a higher oxygen content (lean mixture), there will be a small ion migration through the sensor, generating a lower voltage (080 mV).

HOT-FILM AIR MASS SENSOR

Hot-film air mass sensor is non-adjustable. A faulty hot-film air mass sensor can make engine difficult to restart when engine is hot, engine starts then stalls, malfunction indicator light illuminated, or engine starts and runs only with accelerator pedal depressed. Hot-film air mass sensor can be tested with DISplus/GT1, DISplus/GT1 status page, and the DISplus/GT1 oscilloscope which requires taking the measurement with the ECM and the universal adapter connected to the circuit (engine running).

Visually inspect the sensor for damaged, missing or blocked screens. The screens affect air flow calibration. Also inspect sealing rings where sensor inserts in air filter housing and intake boot. Ensure pin connections are tight.

THROTTLE POSITION SENSOR

Throttle position sensor can be tested with BMW DISplus system or DISplus oscilloscope. When using oscilloscope, select from present measurement which requires taking the measurement with the ECM and the universal adapter connected to circuit. (Scheme 35)

Scheme 35

RELAYS

For fuel pump relay, see FUEL DELIVERY under FUEL SYSTEM. For relay location or location of relay box, see RELAY LOCATION table. (Scheme 36)- (Scheme 61).

RELAY LOCATION

Scheme 36

Scheme 37

Scheme 38

Scheme 39

Scheme 40

Scheme 41

Scheme 42

Scheme 43

Scheme 44

Scheme 45

Scheme 46

Scheme 47

Scheme 48

Scheme 49

Scheme 50

Scheme 51

Scheme 52

Scheme 53

Scheme 54

Scheme 55

Scheme 56

Scheme 57

Scheme 58

Scheme 59

Scheme 60

Scheme 61

FUEL DELIVERY

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

Before any service work is performed on any fuel system related component, always adhere to the following

1. Observe relevant safety legislation pertaining to your area.
2. Ensure adequate ventilation.
3. Use exhaust extraction system where applicable (alleviate fumes).
4. Do not operate the fuel pump unless it is properly installed in the fuel tank and is submersed in the fuel (fuel lubricates the pump).
5. Always wear adequate protection clothing including eye protection.
6. Use caution when working around a hot engine compartment.
7. During fuel system repair that involves "sealing rings" always replace them with new copper rings only.
8. BMW does not recommend any unauthorized modifications to the fuel system. The fuel system is designed to comply with strict federal safety and emissions regulations.
9. Fuel quality should always be considered when diagnosing a driveability complaint. The type of fuel, proper AKI rating, impurities and moisture are not factored by the ECM.

Fuel Pump Relay

Remove fuel pump relay. See RELAY LOCATION table. 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. 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. 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 «RELAY LOCATION»(/bmw/z4/e85e86-2002-2005/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). Catch and dispose of escaping fuel. See «FUEL PRESSURE & DELIVERY PERFORMANCE»(/bmw/z4/e85e86-2002-2005/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/z4/e85e86-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing) table.

FUEL PRESSURE & DELIVERY PERFORMANCE

Scheme 62

Preliminary Check

1. Injectors should be tested using DISplus/GT1 for resistance, power supply, status display-fuel injection signal, and ECM final stage transistor activation. These test functions are found under the oscilloscope preset list. Install universal adapter, diagnostic cable, negative lead to ECM ground and positive lead to the ground activation circuit for the injector. This test is performed with the engine cranking or running.
2. Fuel supply hardware should be visually inspected for damage that can affect pick-up, transfer, pressure and return. The fuel tank must be drained first before removing the service access cap to perform any repair. The fuel filter, fuel pressure regulator, electric fuel pump, right fuel level sensor and siphon jet are accessed through the service access cap. Remove the single 6-pin electrical connector (2 pins for the fuel pump, 2 for each level sensor-left/right). Remove the fuel supply line by releasing the quick release coupling. Fuel tank is secured by 2 straps to the body.

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. 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 44 psi. 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. 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/z4/e85e86-2002-2005/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 AIR ACTUATOR VALVE

Idle air actuator valve and air circuit (passage ways) should be checked for physical obstructions. Visually inspect the sealing gasket, mounting bracket and air hose clamps. Resistance of the valve winding should be checked. ECM output and idle speed control valve operation can be tested by COMPONENT ACTIVATION on DISplus/GT1. Pulse width modulation ground outputs from the ECM can be tested using the DISplus/GT1 oscilloscope. If valve is blocked or contaminated, a fault code can also be present. See IDLE AIR ACTUATOR VALVE LOCATION table. Valve is either a 2-pin or 3-pin type. (Scheme 66)and (Scheme 67).

Scheme 66

Scheme 67

IDLE AIR ACTUATOR VALVE LOCATION

IGNITION SYSTEM

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

Ignition System Testing (Siemmens 2003)

If there is a fault in the secondary ignition, testing should include primary ignition and evaluation of secondary oscilloscope patterns. See BASIC DIAGNOSTIC PROCEDURES article.

Scheme 68

Scheme 69

Scheme 70

Scheme 71

Scheme 72

Scheme 73

1. Using DISplus/GT1, read out fault memory in Digital Motor Electronics (DME). Remove sound absorption hood or ignition coil cover as necessary. Open control unit box. Unlock plug fastener of ignition coil. (Scheme 68) Detach plug in direction of arrow. Pull out ignition coil toward top. (Scheme 69)
2. Install Adapter Lead (127050) between spark plug and rod-type ignition coil. (Scheme 70) Connect clip-on trigger sensor of DIS Tester to adapter lead. (Scheme 71) Perform following procedure on DIS tester: Select MEASUREMENT. Select PRESET MEASUREMENT. Select SECONDARY IGNITION SIGNAL. Connect TD cable to diagnostic head. Select STATIONARY IGNITION DISTRIBUTOR SYSTEM. Select CYLINDER NUMBER. For subsequent procedure, follow DIS instructions.
3. Primary Measurement: Connect 26-pin pin box with Adapter Lead (121301) to connector of DME module. On DIS tester, perform following procedure: Select MEASUREMENT. Select PRESET MEASUREMENT. Select IGNITION SIGNAL TERMINAL. For subsequent procedure, follow DIS instructions. Ignition signal is a multiple spark ignition. (Scheme 72) NOTE: Ignition oscillogram applies to engines with multiple spark ignition from a production date of 4-2001 and after. Depending on engine temperature of about -4 to 211°F (-20 to 100°C) and engine speed (less than 2000 RPM), some ignition voltage peaks (about 1-5 ignition peaks) can occur before the typical ignition voltage characteristic. The additional ignition peaks play a role in diagnosis. The last ignition peak on the oscillogram is decisive. (Scheme 73) The display of the ignition voltage peak is about 20-25 percent lower than the real value. It is not the height of the ignition voltage peaks but rather the uniformity of all the cylinders that is important. Differences of 3000-4000 volts are permitted.

Ignition Coil Resistance

Measure primary coil resistance between terminal No. 1 and terminal No. 15. (Scheme 74) Secondary coil resistance cannot be measured. See IGNITION COIL RESISTANCE table.

Scheme 74

Scheme 75

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 75) 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

Measure primary coil resistance between terminal No. 1 and terminal No. 15. see scheme 48 Secondary coil resistance cannot be measured. See IGNITION COIL RESISTANCE table.

IGNITION COIL RESISTANCE - Ohms @ 68°F (20°C)

Ignition Coil Secondary Signal Check

1. Connect engine analyzer and Adapter (127020) as described in «IGNITION COIL PRIMARY SIGNAL CHECK»(/bmw/z4/e85e86-2002-2005/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 76)
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 76

Scheme 77

Scheme 78

1. Set pressure regulator on Tester (16 1 171) fully in "-" direction. Connect tester via compressed air line to workshop/garage compressed air system with a pressure of 116-145 psi. Connect pressure sensor of BMW Diagnosis and Information System (DIS) with a measuring range of 0-50 psi (0-3.5 bar). Select Adapter (16 1 172 or 16 1 173) matching vehicle's filler cap and attach to quick-release coupling of tester. (Scheme 77)and (Scheme 78).
2. Install filler cap on appropriate adapter. Only the absolute pressure is indicated in the display of the DIS. The current ambient air pressure is already displayed without additional pressurization.
3. Ensure testing equipment is okay by checking testing equipment for leaks. Select MEASUREMENT function on DIS. Increase pressure by 2.9 psi (.2 bar) with pressure regulator on tester. Using Hose Clip (13 3 010), disconnect delivery line from tester to fuel filler neck. Wait 60 seconds. Read off final pressure value and compare with starting pressure value. If pressure drop is greater than.174 psi (.012 bar) testing equipment is leaking. Check connection joints for leaks.
4. Check filler cap pressure relief valve by following same test procedure for checking testing equipment for leaks in step 3. Increase pressure by 4.3 psi (.3 bar) with pressure regulator on adapter. If pressure drop is greater than.174 psi (.012 bar), filler cap pressure relief valve is faulty. Replace filler cap.

Fuel Tank Vent (Evaporation) Control Valve

For location of fuel tank vent (evaporation) control valve on models where this information is available, 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.

Draining & Filling Fuel Tank

1. Ensure adequate ventilation is present. Connect exhaust and extraction systems to exhaust tailpipe. Carefully withdraw extraction hose, avoiding damage to non return flap. Electric fuel pump must not operate without fuel. After repair work, but before starting engine for first time, fill fuel tank with minimum of.5 qt. (.5L) fuel through fuel filler pipe.
2. To draw off fuel, start engine and allow to run. Electric fuel supply pump will operate. Fuel is pumped via suction jet pump and tank expansion line from left to right side of fuel tank. NOTE: Fuel can be drawn off from left and right tank halves through fuel filler pipe down to a small residual amount. Residual amount on left and right can continue to be drawn off after removal of fuel filter.
3. Push extraction hose of suction extractor unit into fuel filler pipe about 35 inches. Turn slightly if necessary. Draw off fuel with suction extractor unit as much as possible. Catch dripping fuel in a container. Remove fuel filter. Draw off residual fuel amount in right tank half through service opening. To draw off residual fuel on left side, feed extraction hose through service opening in tank above saddle into left tank half. Residual fuel amount can be drawn off.
4. To refill, push extraction hose of suction extractor unit about 35 inches into fuel filler pipe. Fill fuel from suction extractor unit.

Leak Diagnosis Test - X5

Note. For leak detection (Scheme 79)and (Scheme 80).

Scheme 79

Scheme 80

Checking Fuel Tank & Tank Venting System For Leaks With Tank Leakage Diagnosis Module (DM-TL) - Z3

1. A fault is indicated by CHECK ENGINE indicator light in instrument cluster lighting up. This may indicate a leak in the tank venting system. Information on this is provided by the fault memory of the DME control unit. Read out fault memory of DME control unit and carry out diagnosis in accordance with faults stored. A leak test with the DM-TL module is then carried out if: The components of the DM-TL module are okay. An error is stored in the DME fault memory (tank leak detected).
2. Adhere to following conditions in order to carry out a correct leak test: Ensure content of fuel tank is greater than 90 percent. Ensure reserve indicator light is off. Leave car in workshop for at least 2 hours so that fuel temperature equals workshop temperature as closely as possible (ideal fuel temperature is about 50-68°F (10-20°C). Do not under any circumstances fill up car with fresh fuel. Check that tank cap is correctly seated. WARNING: During leak test, under no circumstances apply external pressurization through tank filler neck as this may cause incorrect readings.
3. Clear DME fault memory. Using Diagnosis and Information System (DIS), go to FUNCTION AND COMPONENT SELECTION page by selecting COMPLETE VEHICLE, DRIVE, ENGINE MANAGEMENT, TANK SYSTEM TEST, DIAGNOSIS MODULE TANK LEAKAGE (DMTL). Adopt test module in test schedule. Switch to test schedule and implement tank leakage diagnosis module. Leakage test is carried out. If fault is recorded again in DME fault memory (tank leak detected), go to next step and carry out leak test. CAUTION: On vehicles with Tank Leak Diagnosis Modules (DM-TL), do not work with external pressurization as the tank venting system will leak under this condition. Because of emerging fuel vapors, carry out all work in well ventilated rooms, or use a suitable extractor system. NOTE: Following procedure is only applicable to vehicles with tank leak diagnosis module (DM-TL).
4. To conduct leak test on fuel tank and tank ventilation system, in Diagnosis and Information System (DIS), go to FUNCTION AND COMPONENT SELECTION page by selecting: SERVICE FUNCTIONS, DRIVE, DIGITAL MOTOR ELECTRONICS AND ACTIVATION DMTL PUMP ADOPT TEST MODULE in test schedule. Switch to test schedule and implement ACTIVATION DMTL PUMP test module.
5. Tank leak diagnosis pump pressurizes fuel tank and tank venting system. Carry out leak test. Terminate test module after completing leak test. Tank leak diagnosis pump is automatically shut down after about 15 minutes due to risk of overheating. Allow pump to cool down for at least 15 minutes, then continue procedure. Leak test can be carried out with a leak detector. Follow leak test manufacturer's operating instructions. Possible causes of leaks are: Tank cap leaking (check tank cap pressure relief valve). See «FUEL CAP PRESSURE RELIEF VALVE TEST»(/bmw/z4/e85e86-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing) under FUEL EVAPORATION. Tank venting lines leaking (fuel tank, carbon canister, or tank venting valve). Tank ventilation valve leaky (engine compartment). Fuel level sensor flange on tank leaking.

Scheme 81

Scheme 82

Scheme 83

Scheme 84

1. Do not work with external pressurization as tank venting system will leak. Because of escaping fuel vapors, these tasks should only be carried out in well ventilated rooms or with a suitable extractor facility provided. Using BMW Diagnosis and Information System (DIS), go to FUNCTION AND COMPONENT SELECTION page by selecting: SERVICE FUNCTIONS, DRIVE, DIGITAL MOTOR ELECTRONICS, ACTIVATION DMTL PUMP and ADOPT TEST MODULE in test schedule. Switch to test schedule and implement ACTIVATION DMTL PUMP TEST MODULE VENTING. (Scheme 81)- (Scheme 84).
2. Tank leak diagnosis pump pressurizes fuel tank and tank venting system. Carry out leak test. Terminate test module after completing leak test. Tank leak diagnosis pump will automatically shut down after about 15 minutes due to risk of overheating. Allow pump to cool down for at least 15 minutes, then continue procedure. Leak test can be carried out with a leak detector. Follow manufacturer's operating instructions. Possible causes of leaks are: Tank cap leaking. See «FUEL CAP PRESSURE RELIEF VALVE TEST»(/bmw/z4/e85e86-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing) under FUEL EVAPORATION. Tank vent line leaking (fuel tank-carbon canister). Tank vent line leaking (engine compartment). Sealing ring on fuel filter leaking.

Checking Fuel Tank & Tank Venting System For Leaks With Tank Leakage Diagnosis Module (DM-TL) - Z8

1. For vehicles without tank leak diagnosis module, go to step 3 . For vehicles with tank leak diagnosis module, go to next step. CAUTION: On vehicles with tank leak diagnosis modules (DM-TL), do not work with external pressurization as the tank venting system will leak under this condition.
2. Select 4 EXPERT MODE function on Diagnosis and Information System (DIS). From menu, 2 ACTIVATE COMPONENTS, select function 127 ACTIVATION DMTL PUMP. DMTL PUMP appears in display. Pump is activated. Tank leak diagnosis pump pressurizes fuel tank and tank venting system.
3. On vehicles without tank leak diagnosis module, pressurize tank through filler neck. When leak-testing with a leak detector, follow manufacturer's operating instructions. On account of emerging fuel vapors, carry out all operations in well ventilated rooms, or use a suitable extractor system.
4. Possible causes of leaks may be: Tank cap leaking (check tank cap pressure relief valve). See «FUEL CAP PRESSURE RELIEF VALVE TEST»(/bmw/z4/e85e86-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing) under FUEL EVAPORATION. Tank venting lines leaking (fuel tank, EVAP carbon canister or tank venting valve). Tank venting valve leaking (engine compartment). Fuel level sensor flange on tank leaking.

Checking Fuel Tank & Tank Venting System For Leaks With Tank Leakage Diagnosis Module (DM-TL) - 3-Series (E46)

1. Remove screws and panel. Remove expansion rivet and panel. (Scheme 85) Unlock line and detach line from dust filter. (Scheme 86) Seal dust filter with special tool. Remove tank filler cap and connect Special Tool (16 1 150) to tank filler neck. (Scheme 87) 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 88) 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 is 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 85

Scheme 86

Scheme 87

Scheme 88

Checking Fuel Tank & Tank Venting System For Leaks With Tank Leakage Diagnosis Module (DM-TL) - 5-Series (E39) 6-Cylinder

1. If a leak in the tank ventilation system is indicated by CHECK ENGINE indicator lamp in the instrument cluster, a leak test must be carried out. First, fault memory of DME control unit must be read out and diagnosis conducted. If sensors are okay, then begin leak test. Following conditions must be observed to obtain plausible measuring results: Ensure contents of fuel tank are 25-75 percent. Park vehicle in workshop at least 2 hours before test so fuel temperature is about that of workshop temperature. Ideal fuel temperature is 50-68°F (10-20°C). Never refuel the vehicle directly prior to leak test due to strong gas emission by fresh fuel.
2. To conduct leak test, remove luggage compartment mat and spare tire. Remove battery cover. Remove hexagon nut and plastic nut. (Scheme 89) Remove cover of activated carbon canister upward.
3. Disconnect electrical connector of activated carbon canister non return valve. (Scheme 90) Connect Special Tool (12 6 410/411) to activated carbon canister non return valve and vehicle battery. (Scheme 91) 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 87)
4. 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 88) 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.
5. 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 (.10 bar), as damage to fuel tank and tank ventilation system is possible.
6. 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.
7. 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 89

Scheme 90

Scheme 91

Checking Fuel Tank & Tank Venting System For Leaks With Tank Leakage Diagnosis Module (DM-TL) - 5-Series (E39) V8

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 92) 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 87) 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 88) WARNING: 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.
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 (.05 bar) with pressure regulator. WARNING: Do not increase pressure by more than 1.45 psi (.10 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 92

Scheme 93

Scheme 94

1. An OBD fault is indicated by CHECK ENGINE light in instrument cluster. This may indicate a leak in the tank venting system. Information on this is provided by the fault memory of the DME control unit. Read out fault memory of DME control unit and carry out diagnosis in accordance with faults stored. (Scheme 93)and (Scheme 94). A leak test with the DM-TL module is then carried out if: The components of the DM-TL module are okay. A error is stored in the DME fault memory (tank leak detected).
2. To carry out a correct leak test, ensure content of fuel tank is less than 90 percent and reserve indicator lamp is off. Leave car in workshop for at least 2 hours so that fuel temperature comes into line with workshop temperature. Ideal fuel temperature is approximately 50-68°F (10-20°C). Do not under any circumstances fill up car with fresh fuel as there is a strong exhalation of fresh fuel. Check that tank cap is correctly seated. WARNING: During leak test, under no circumstance apply external pressurization through the tank filler neck as this may cause an incorrect reading.
3. Clear DME fault memory. In Diagnosis and Information System (DIS), go to FUNCTION AND COMPONENT SELECTION page. Carry out tank leakage diagnostic module. If a fault is stored again in DME fault memory (tank leak detected), carry out leak testing. Go to «CONDUCTING LEAK TEST ON FUEL TANK & TANK VENTILATION SYSTEM»(/bmw/z4/e85e86-2002-2005/remont/testing-diagnostics/#engine-controls-system-component-testing__conducting-leak-test-on-fuel-tank).

Conducting Leak Test On Fuel Tank & Tank Ventilation System

1. For vehicles without tank leak diagnosis module, go to next step. For vehicles with tank leak diagnosis module, on Diagnosis and Information System (DIS), select CONTROL UNIT FUNCTIONS for DME MOTOR ELECTRONICS ME9 control unit. Select COMPONENT ACTIVATION from FUNCTIONS column. From SUBFRAMES column, select TANK LEAK DIAGNOSIS MODULE: ACTIVATE PUMP function. Press ACTIVATE button. Tank leak diagnosis pump pressurizes the fuel tank and tank venting system for 30 seconds. If pressure is required for longer than 30 seconds, you must press the ACTIVATE button again after 30 seconds. Go to step 3 .
2. For vehicles without tank leak diagnosis module, pressurize through filler neck. When leak testing with a leak detector, follow manufacturer's operating instructions. Observe country-specific accident prevention and occupational safety regulations. Go to next step.
3. Possible causes of tank leakage may be tank cap leaking (check tank cap pressure relief valve), tank venting lines leaking (fuel tank, carbon canister or tank venting valve), tank venting valve leaking (engine compartment), or fuel level sensor flange on tank leaking.

See also:
• BASIC DIAGNOSTIC PROCEDURES
• SELF-DIAGNOSTICS - EXCEPT 7-SERIES
• PIN VOLTAGE CHARTS
• DME CONTROL UNIT LOCATION
• FUEL DELIVERY
• FUEL PRESSURE REGULATOR
• FUEL INJECTOR LEAKAGE
• CONDUCTING LEAK TEST ON FUEL TANK & TANK VENTILATION SYSTEM