Yes, a replacement CSU is available for the 2016+ Pike DJ A2-A4. The replacement CSU is part number 11.4018.008.494 (FORK CSU - SOLO AIR 26 40 OFF-SET ALUMINUM TAPER BLACK (NO GRADIENTS)(.5 THREAD PITCH) -PIKE DJ A2-A4 (2016+)).
RockShox service kits and spare parts are best obtained through your local shop or dealer. See our dealer locator, below, to find a dealer near you. If no one is currently listed near you, then please search for local shops via your preferred web browser.
https://www.sram.com/en/dealer-locator
Manuals and additional information about RockShox and SRAM components can be found at our service site, linked below.
https://www.sram.com/en/service
Further questions?
Reach out to Rider Support by Asking A Question at the link below.
https://www.sram.com/en/rockshox/campaigns/rockshox-rider-support