Authors Note: Keep in mind, this guide contains spoilers. Albeit nothing game breaking, I have tried my best to avoid where necessary. This guide will tell you How to Complete Spare Parts In Detroit Become Human The Best Way possible.
Additionally, this will ONLY work if you have done a good playthrough (Markus does non-violent protests when freeing the Cyberlife Androids, Marks does peaceful demonstrations and gatherings and no Casualty in Channel 16, Basically, anything that involves killing an NPC voluntarily outside of a QTE i.e. The Police, will result in risking the chances of the others surviving)
If you wish to find guides for the other people, you will find them attached below:
- How to Save Markus in Detroit Become Human
- How to Save Connor in Detroit Become Human (This includes Hank)
- How to Save Jericho People in Detroit Become Human (This includes Simon, North, and Josh)
- How to Save Other Characters in Detroit Become Human (This has misc. characters like Jerry, Luther, and Chloe)
How to Complete Spare Parts In Detroit Become Human The Best Way
Spare parts is one of the first excursions that Markus and the people of Jericho that includes North, Josh and Simon the butler turned Android rights activist set out to acquire blue blood and spare parts for the massive number of people who desperately need it in Jericho.
The first half of the stage is straightforward and very linear. All you have to do is follow the sequence of Quick Time Events (QTE) until you reach the containers of blue blood.
While you are looting the containers, an android security guard will threaten to raise the alarm and a human guard is also not far behind him. You have to choose the GRAB AND HIDE option and keep the android quiet until the human guard passes through the containers.
When you have the choice, the same guard will ask to go with you, and initially, you might be hesitant on letting the android accompany you but if you choose to Accept, there are more benefits than you might know.
If you Refuse the offer, he will sound the alarm and you have to make a hasty retreat.
However, accepting the android gives you access to a bonus side mission where he tells you about the autonomous trucks that carry literal truckloads of biocomponents (spare parts) that are also a desperate need of the people of Jericho.
The only problem? To turn the trucks from auto-pilot to manual, you need to steal the key from a nearby guard station that currently has 2 guards watching the gate and also the key.
North will tell you that it is a bad idea and will try to deter you from it, but it’s actually not as risky as it sounds.
You must choose to accept the task and steal the spare parts mission, You have a 10-minute countdown timer, but don’t let that intimidate you, you will be done in a couple of minutes at best.
When you have resumed control of Markus, you will see the guard station directly across the containers you just looted. Head towards it and try to follow the back wall as much you can until you see a small service window, before it you will see the main door, which is a no-go, a smaller window running along the left wall of the main door and then right down that window is another window which Markus can jump into. 
When you jump into the far left window that gives you access to a bathroom. you have to carefully sneak in and notice a lot of the things. You have to notice the guards, the key on the far left of the control panel and Markus will think to himself how he can steal the key without getting noticed.
Whatever you do, DON’T PICK UP THE GUN on the station near to you. There are better approaches you can adopt.
When Markus says that he needs to get the guards away from the key, climb back out of the Bathroom window and head back to where you came from towards some red barrels. Interact with them a couple of times to give Markus the prompt to knock them over.
When the barrels are knocked over, you need to make a dash for the Bathroom window again while the guards investigate the noise. Go back inside the station, head towards the now empty console and steal the key.
Alternatively, you can also steal the screwdriver from a nearby toolbox and jam it into the big blue server rack next to the main door of the guard house. This will cause a blackout but you have to be careful in sneaking around as even getting near a guard can turn the whole mission into a problem.
With all that done, now you make your way back outside the same way you came in to see the guards are back at their posts, none the wiser.
You return to your Jericho crew, earning their respect and with a whole load of parts that the people of Jericho desperately need!
From here on, you play a scripted scene, don’t worry about being detected or an inspection as the guards are too lazy to investigate the truck departure.
We hope that our guide, Complete Spare Parts In Detroit Become Human, helped you feel like a better leader of Jericho, and if you have any comments, questions, or feedback, please drop them in the comments section below and I will be glad to help you with the game!