Fails Leak Test - Bosch ACS 561 Repair Instructions

Diagnostics and Testing
6. Check the oil inject solenoid for bleed-
through and proper operation. This can be
done by checking for suction at the oil inject
tube in the oil inject bottle. Remove the oil
inject bottle during the vacuum process and
check for suction at oil inject tube or watch
for oil movement in the tube towards the
manifold. Repair as needed.
7. Check the charge solenoid if pressure rises
above zero (0) when the unit is off.
8. Verify the low side pressure transducer is
functioning properly.
Vacuum Pump Not Running
1. Check gauges for vacuum.
2. If pressure is over 690mBar (10 psi), recover
hoses. If unit won't maintain vacuum, check
the following for leakage:
• Charge solenoid (S3)
• Hose couplers
• Hoses
• Gauge tubing
• Bulkhead/Oil inject manifold
• Suction side vacuum hoses and connec-
tions
3. If there is no pressure on gauges and dis-
play says Pressure Exists, enter the service
menu and verify low side inlet transducer
reading. If it is reading pressure where none
exists, replace transducer. If replacing the
transducer doesn't correct the reading, re-
place the power board.
4. Refer to "Vacuum Pump Does Not Run for
electrical troubleshooting.
SP00D00517 2018-07-11

Fails Leak Test

To ensure an accurate leak test, it is
imperative that a thorough recovery and
evacuation of the system be performed.
During the recovery process, cold spots
can develop in the automotive system.
Pockets of refrigerant in desiccant and
in system oil will continue to vaporize
as the A/C system temperature equal-
izes toward ambient. As this occurs, A/C
system pressure will increase, which
may be interpreted by the unit as a leak.
This will vary somewhat with ambient
temperature conditions.
1. Verify the service hoses are properly at-
tached to the unit (valves open) without
any restrictions. Verify the connections of
the quick couplers and gauges (with their
adapters and plastic hoses).
2. If vacuum can not be maintained, using
Service Leak Check in the service menu,
pressurize the unit and use a leak detector
to check all hoses, fittings and components
for leaks. Repair as needed.
3. Check the charge (S3), oil inject (S5), and
vacuum solenoids (S2) for bleed-through.
Repair as needed.
A leaking charge solenoid (S3) could be
identified by an internal pressure rise
above zero. A leaking vacuum (S2) or oil
inject solenoid (S5) would not normally
rise above zero.
4. Verify the low-side pressure transducer is
functioning properly. Enter service menu
and verify low side inlet transducer reading.
• If the low-side inlet transducer is read-
ing pressure while the system is in a
vacuum, replace the transducer. Verify
the replacement transducer reads zero at
atmosphere by plugging it into the wiring
harness prior to installation.
• If replacing the transducer doesn't correct
the reading, replace power board.
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ACS 561 Service Manual
Robert Bosch GmbH