Ground, Power & Input/Output Circuits
Testing information is not available from manufacturer. See PIN VOLTAGE CHARTS and WIRING DIAGRAMS sections to identify DME/Motronic control unit ground circuits, power circuits and input/output circuits. See DME/MOTRONIC CONTROL UNIT LOCATION table.
| Application | Location |
|---|---|
| All Models | 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 table. See appropriate RESISTANCE SPECIFICATIONS table under SPECIFICATIONS.
| Application | Location |
|---|---|
| All Models | On Front Left Side Of Engine, Below Intake Manifold |
ENGINE (COOLANT) TEMPERATURE SENSOR LOCATION
INTAKE AIR TEMPERATURE SENSOR
Intake air temperature sensor is mounted in intake manifold near mass airflow meter assembly. See appropriate RESISTANCE SPECIFICATIONS table under SPECIFICATIONS .
RELAYS
For fuel pump relay, see FUEL DELIVERY under FUEL SYSTEM. Additional information is not available from manufacturer. For relay locations, see DME/MOTRONIC SYSTEM RELAYS LOCATION table.
| Application | (1) Location |
|---|---|
| 325i, 325iC, 325is | (2) Behind Cover, Along Engine Compartment Firewall |
| 525i & 525iT | (2) Right Inner Fender Panel Of Engine Compartment |
| (1) (Scheme 20) (2) First relay (viewed from left to right) after ground wire is fuel pump relay followed by Digital Motor Electronics (DME) master relay. | |
| (1) | (Scheme 20) |
| (2) | First relay (viewed from left to right) after ground wire is fuel pump relay followed by Digital Motor Electronics (DME) master relay. |
DME/MOTRONIC SYSTEM RELAYS LOCATION
Scheme 20
Scheme 21
FUEL DELIVERY
Note. For fuel system pressure testing, see BASIC TESTING article.
Fuel Pump Relay
Remove fuel pump relay. Apply battery voltage to relay terminals No. 30 and 86. (Scheme 22) 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 section. Only sockets No. 2, 4, 6 and 8 are used by relay.
Scheme 22
Fuel Injector
Individual fuel injector resistance should be 15-17 ohms. See appropriate RESISTANCE SPECIFICATIONS table under SPECIFICATIONS.
IDLE SPEED CONTROL VALVE
See IDLE SPEED CONTROL VALVE LOCATION table. See appropriate RESISTANCE SPECIFICATIONS table under SPECIFICATIONS .
| Application | Location |
|---|---|
| All Models | At Left Front Of Engine, Near Dipstick |
IDLE SPEED CONTROL VALVE LOCATION
IGNITION SYSTEM
Note. For basic ignition checks, see BASIC TESTING article.
Fuel Tank Vent (Evaporation) Control Solenoid
See FUEL EVAPORATION CONTROL SOLENOID LOCATION table. See appropriate RESISTANCE SPECIFICATIONS table under SPECIFICATIONS .
| Application | Location |
|---|---|
| 325i, 325iC & 325is | On Left Shock Tower |
| 525i & 525iT | Next To Dipstick |
FUEL EVAPORATION CONTROL SOLENOID LOCATION