Bosch PCE Coolant Pumps

2026-02-14T16:30:57Z

Lolimpol: Added PWM signal control table to signify the pump can be turned off without removing the power supply.

== Important Note on Bosch vs VW pumps ==
Although both companies use pumps from the "PCE"-series, a closer look at the pump connector reveals an important difference: Bosch pumps have the key nearer to the centre (pin 2) and have the pinout 1 (gnd), 2 (signal), 3 (12V). By contrast, VW pumps have the key closer to the leftmost pin (pin 1) and have the pinout 1 (gnd), 2 (12V), 3 (signal). Also note that, although both brands have "Bosch" on the label, the VW-branded ones also have a "VW-AG" marking.

== Connector Part Numbers <ref>https://www.bosch-ibusiness.com/products/product-categories/auxiliary-pumps-and-valves/pce-0392024078/</ref><ref>https://www.bosch-ibusiness.com/media/images/xx_pdfs_4/katalog_2023.pdf#page=62</ref> ==

=== VW pumps ===
'''Pigtail'''

* VW: 4F0 973 703

'''Housing'''

* TE Connectivity "MCON 1.2" series: 1488991-5 (key A)
* Molex "MXP120" series: 34900-3101 (key A)

'''Terminals'''

* Bosch: 1 928 498 811
* Tyco/Molex MCON 1.2" series: 1670146-3 – Ag plated (20awg)
* KOSTAL MLK 1.2: 32124734130

'''Seal'''

* Bosch: 1 928 300 936
* TE Connectivity: 967067-1 (20 awg)
* KOSTAL: 10800507250
'''Pinout'''
[[File:VW 04L 965 567.jpg|none|thumb|VW 04L 965 567 pump. Note the pinout and the position of the key vs the Bosch-branded pump.]]

=== Bosch pumps ===
'''Housing'''
* TE Connectivity "MCON 1.2" series: 1488991-6 (key B)
* Molex "MXP120" series: 34900-3102 (key B)

'''Terminals'''

* Bosch: 1 928 498 811
* Tyco/Molex MCON 1.2" series: 1670146-3 – Ag plated (20awg)
* KOSTAL MLK 1.2: 32124734130

'''Seal'''

* Bosch: 1 928 300 936
* TE Connectivity: 967067-1 (20 awg)
* KOSTAL: 10800507250
'''Pinout'''[[File:Pce connector.webp|none|thumb|Bosch-branded PCE pump pinout (**not for VW**)]]

== Operation ==
Pump can be run without the signal (S) pin connected. This will operate the pump at maximum speed. There is a 2 second startup delay if the pump is to be operated without the signal (S) pin connected.
[[File:Mounting orientations.png|none|thumb]]
If the pump detects that it is being run dry, it will turn itself off, try again, but will quit if unsuccessful >20 times

Signal pin can be provided a 12V PWM to control the speed<ref name=":0">https://www.cascadiamotion.com/images/documents/Bosch_PCE-XL_Quick_Start_Guide.pdf</ref>

=== PWM Scheme<ref name=":0" /> ===

* Terminal “S” driven with: +12V (nominal) PWM controlled, 9 to 110Hz. (nominal = 100Hz)
* If there is no PWM signal within 2 seconds of power-on, the default mode of full speed operation will be used.
* If there is a valid PWM signal, a speed-proportional response to a commanded 12-93% duty cycle will be delivered.
{| class="wikitable"
|+PWM signal control table
!Duty cycle
!Pump function
!Pump speed
|-
|0-7%
|Fail safe mode
|100%
|-
|7-8%
|Fail safe hysteresis
|0 or 100%
|-
|8-13%
|Pump off
|0%
|-
|13-93%
|Pump running
|0-100%
|-
|93-100%
|Fail safe mode
|100%
|}
(The highest duty cycle failsafe mode was not tested but taken over from an extremely similar table from Cadcadia Motion<ref name=":0" />)

== Mounting ==
One application (i.e. Cascadia Motion) simply uses a massive (as in 80mm diameter) "p clamp" to secure the pump. For those looking for something more secure/OE: [https://www.printables.com/model/1013391-bosch-pce-coolant-pump-bracket Bosch PCE Coolant Pump Bracket.]

= References =
<references />
[[Category:VAG]]
[[Category:water pumps]] [[Category:Bosch]]

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Bosch PCE Coolant Pumps