Ground, Power & Input/Output Circuits
Testing information is not available from manufacturer. Refer to the PIN VOLTAGE CHART S and WIRING DIAGRAMS articles to identify DME/Motronic control unit ground circuits, power circuits and input/output circuits.
| Application | Location | ||
|---|---|---|---|
| 325 Series | Under Right Side Of Dash, Behind Glove Box | ||
| 525 | Inside Box On Right Rear Corner Of Engine Compartment, Behind Strut Tower | ||
DME/MOTRONIC CONTROL UNIT LOCATION
CRANKSHAFT (SPEED/POSITION PULSE) SENSOR
Crankshaft (speed/position pulse) sensor is located on front right side of engine, next to crankshaft pulley. See appropriate RESISTANCE SPECIFICATIONS table under SPECIFICATIONS.
ENGINE (COOLANT) TEMPERATURE SENSOR
See ENGINE (COOLANT) TEMPERATURE SENSOR LOCATION and appropriate RESISTANCE SPECIFICATIONS tables under SPECIFICATIONS.
| Application | Location |
|---|---|
| 325i, 325iC, 325is & 525i | On Front Left Side Of Engine, Below Intake Runners |
ENGINE (COOLANT) TEMPERATURE SENSOR LOCATION
INTAKE AIR TEMPERATURE SENSOR
Intake air temperature sensor is part of air mass sensor/airflow meter assembly. See appropriate RESISTANCE SPECIFICATIONS table under SPECIFICATIONS.
RELAYS
| Application | (1) Location |
|---|---|
| 325i, 325iC & 325is | On Left Rear Corner Of Engine Compartment, In Fuse/Relay Block |
| 525i | On Right Rear Corner Of Engine Compartment, Next To DME Control Unit |
| (1) (Scheme 8) | |
| (1) | (Scheme 8) |
DME/MOTRONIC SYSTEM RELAYS LOCATIONS
Scheme 8
FUEL DELIVERY
Note. For fuel system pressure testing, see BASIC TESTING article in this section.
Fuel Pump Relay
Remove fuel pump relay. Apply battery voltage to relay terminals No. 30 and 86. (Scheme 9) 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 in this section. Only sockets No. 2, 4, 6 and 8 are used by the relay.
Scheme 9
Fuel Injector
See appropriate RESISTANCE SPECIFICATIONS table under SPECIFICATIONS.
IDLE SPEED ACTUATOR
See IDLE SPEED ACTUATOR LOCATION and appropriate RESISTANCE SPECIFICATIONS tables under SPECIFICATIONS.
| Application | Location | ||
|---|---|---|---|
| 325i, 325iC, 325is & 525i | On Center Left Side Of Engine, Below Intake Runners/Throttle Body | ||
IDLE SPEED ACTUATOR LOCATION
IGNITION SYSTEM
Note. For basic ignition checks, see BASIC TESTING article in the ENGINE PERFORMANCE Section.
Fuel Tank Vent (Evaporation) Control Valve
See FUEL EVAPORATION CONTROL VALVE LOCATION and appropriate RESISTANCE SPECIFICATIONS tables under SPECIFICATIONS.
| Application | Location | |
|---|---|---|
| 325i, 325iC, 325is & 525i | On vacuum hose, directly below airflow meter assembly. | |
FUEL EVAPORATION CONTROL VALVE LOCATION
MISCELLANEOUS CONTROLS
Note. Although some of the controlled devices listed here are not technically engine performance components, they can affect driveability if they malfunction.