Vacuum Pump Troubleshooting - Bosch ACS 653 Repair Instruction

Diagnostics and Testing

Vacuum Pump Troubleshooting

1. Check gauges for vacuum.
2. If pressure is over 0.7 bar (10 psi), recover
hoses.
3. If unit won't maintain vacuum, check
high- and low-side charge solenoids,
hoses, couplers, gauges, and other related
components, for leakage.
4. If there is no pressure on the gauges and
the display 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, replace the control board.
5. If the Vacuum Pump is not running or
appears to be running poorly, refer to
Vacuum Pump Does Not Run.
Figure 2-2. Vacuum Pump Assembly
SP00D00624 2021-04-08
ACS 653, ACS 663 Service Manual
Vacuum Pump Does Not Run
1. Check for proper power source, circuit
breaker, and electrical connectors for
damage or corrosion. Replace or repair as
required.
2. Clear service hoses and remove them.
3. Disconnect unit from the power source.
4. Remove the front plastic cover.
5. Connect the unit power cable directly to
the power source. Do not use an extension
cord.
6. Check for 230 V at the vacuum pump
connector, pins 2 and 3.
• If voltage is present, replace vacuum
pump assembly.
• If voltage is not present, continue to next
step.
NOTE: When checking voltage to the vacuum
pump it is normal to read low voltage at the
connector when it's disconnected and the
power to the vacuum pump is off.
7. Check for 230 V from the power board on
connector P6 pins 3 and 4.
• If voltage is present, check wiring between
the power board and the vacuum pump.
Repair as needed.
8. Use the output test and verify fan operation.
• If the fan is not functioning, check/verify
wiring, switches, and circuit breaker.
• If the fan is functioning, replace the power
board.
• If voltage is not present, replace the
power board.
NOTE: If fan works, power is present at the
power board. The fan, vacuum pump, and
compressor use the same power source.
9. Perform functional check.
10. Reinstall the plastic frontal cover.
11. Attach the outside high- (red) and low-side
(blue) service hoses. Tighten at 7.9 Nm
torque.
60
Robert Bosch GmbH