A 5, 7, or 9-pin overvoltage protection relay is installed depending on the vehicle model and special equipment. This relay protects the control units (ABS, CIS-E, etc.) from excessively high voltage.
The battery voltage is present continuously at relay terminal 30. With the 7 and 9-pin versions the battery voltage is also connected to terminal 30a over the 10 A flat plug-in fuse. When the ignition/starter switch is turned to position 2 (driving position), the voltage is present at terminal 15 causing the relay to pull in. Power is supplied to terminals 87 (5-pin version) or 87E and 87L (7 and 9-pin versions).
Voltages > 22 V in the vehicle electrical system are connected directly to ground by the Z diode (fuse defective).
In the event of overloads occurring after the overvoltage cutout, the circuit is interrupted by the 10 A flat plug-in fuse. The 9-pin version is also fused separately at terminals 87E and 87L, whereby when the fuse for 87E blows 87L is also switched off.
Pin | Function |
---|---|
30 | Battery voltage input (12 V) |
31 | Ground |
15 | Ignition switch input |
87E | Fused and diode protected output (12 V) |
87L | Fused and diode protected output (12 V) |
30a | Fused output (12 V) |
The following procedure is a static test for basic relay operation. Passing the following test does not guarantee that the OVP relay is functioning correctly, but will accurately tell if the OVP relay is faulty.
Part Number | Description |
---|---|
201 540 32 45 | 7-pin relay, black top, single 10A fuse |
201 540 38 45 | 7-pin relay, black top, single 10A fuse |
201 540 37 45 | 9-pin relay, red top, double 10A fuse |