How are ABS Accumulator issues diagnosed?
Diagnosis of the ABS brake fluid accumulator is simply done. The servicing technician will read codes from the vehicle that relate to the ABS system, and, if the code returned refers to low brake fluid pressure, the operation of the brake fluid pressure sensor and ABS pump motor must be tested. Once those two components are confirmed to function, the ABS unit will be pressurized, and the brakes will be pressed repeatedly to verify that pressure bleed off is occurring prematurely.
How are ABS Accumulators replaced?
In many vehicles, replacing the ABS accumulator requires replacement of the ABS modulator assembly, which may also include the ABS control module. If the accumulator has failed the self test procedure, and it can be replaced independently, the repair is not typically difficult. First, brake fluid pressure is released from the ABS accumulator to prevent spraying brake fluid once removed. Then, the fasteners securing the accumulator will be removed, and the new accumulator and seals will be installed on the ABS hydraulic unit. Finally, the ABS hydraulic unit and service brakes will be bled of air and tested for proper function.
RepairPal Recommendations for ABS Accumulator issues
Flush and refill the entire brake system when replacing major components. Any debris or contamination from these components may remain in the system and cause repeat failures. Also, the amount of air entering the brake system and ABS system dictates that the system is thoroughly bled to ensure the service brakes remain operational.
What to look out for when dealing with ABS Accumulator issues
The ABS accumulator may be small, but it is under very high pressure. Avoid physical damage to the ABS accumulator, even after it is out of the vehicle. Even when there is no load on the diaphragm, the inert gas inside the canister is still pressurized.