Pierburg CWA Coolant Pumps
Work In progress
The Pierburg CWA Coolant Pumps (200/400) are well known in hot rod engine swaps as they are significant coolant pumps that have the ability to be PWM Controlled, however connecting the PWM pin to +12V permanently also gives 95% speed.
CWA 200
PUMP OEM Part Numbers:
BMW: 11517586925 / 11517586924 / 11517563183 / 11517546994 / 11517545201 / 1151752158
PWM Control:
The Pump can be PWM controlled (Ref 2), however a uninterrupted high pulse of 3ms must be applied at startup(50% duty at 150 Hz).
Duty Cycle:
• 0 – 1% → Stop
• 1 – 7% → Emergency running (about 95% speed)
• 8 – 12% → Stop / Error Reset
• 13 – 85% → Controlled operation from min to max speed
• 86 – 97% → Maximum speed
• 98 – 100% → Emergency running (about 95% speed)
An example curcuit and code using an arduino nano has been demonstrated on the internet site www.instructables.com (Ref 3)
Connector:
4Pin Car Kostal Housing Plug Female: 1JBJ21 9441491 (BMW), 2E0905229 (Merc) Available from Aliexpress
Notes:
The data pin is called BSD. Bit Stream Serial Data. It reports an incredible amount of data including pump rpm , water temp, run time etc.
Useful data/information has been collected on an external ice forum (Ref 4) including using suggestion with using 10k resistor with a low side output to generate a positive 12v pwm.
References:
- https://www.tecomotive.com/en/products/CWA200.html (https://web.archive.org/web/20220126044120/https://www.tecomotive.com/en/products/CWA200.html)
- https://www.tecomotive.com/download/PWMinfo_EN.pdf (https://web.archive.org/web/20220520041935/https://www.tecomotive.com/download/PWMinfo_EN.pdf)
- https://www.instructables.com/Use-an-Arduino-to-Drive-a-Pierburg-CWA200-Car-Elec/ (https://web.archive.org/web/20230711100850/https://www.instructables.com/Use-an-Arduino-to-Drive-a-Pierburg-CWA200-Car-Elec/)
- https://forums.linkecu.com/topic/11204-water-pump-pwm/ (https://web.archive.org/web/20230711101334/https://forums.linkecu.com/topic/11204-water-pump-pwm/)