Dodge Ram with Poor Power Brake Assist
Oct. 04 2022
Oct. 04 2022

Vehicle: 2019 Dodge Ram 1500, 4WD, V8-5.7L, Automatic Transmission/Transaxle

Mileage: 38, 594

Problem: The owner brought his Dodge Ram to the shop because the brake pedal was occasionally hard to press. At idle the power brake operation was excellent.

Case Details: The first thing the technician did was to connect a scan tool and check for diagnostic trouble codes (DTCs). He found only one DTC: C1252-92 – Vacuum Pump Control Circuit – Performance or Incorrect Operation.

RAM Vacuum Pump

A Tech-Assist consultant noted that this truck uses a vacuum pump to supplement engine vacuum so less vacuum from the engine is used to operate the brake power assist. He advised testing the vacuum pump and fuse #33.


The technician found the fuse #33 was blown. He replaced it, but it blew again immediately. He unplugged the vacuum pump and the short was gone. The wiring harness looked fine.

Confirmed Repair: The technician installed a new factory vacuum pump. Fuse #33 didn’t pop, and the brakes worked as designed. Problem solved!

The ALLDATA Tech-Assist team fields cases like this every day. See how Tech-Assist can help your shop save time and money with on-call diagnostic support from ASE-certified Master Technicians. More Tech Tips 

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