Checking Vacuum Pump
Checking the vacuum pump
Checking the electronic additional pump / vacuum pump
- Remove the engine splash guard
- Move the insulation to one side. Detach the vacuum hose for the pump from the T valve
- Left-hand drive cars, see 2
- Right-hand drive cars, see 1.
Note! First check the function of the T valve. See Checking the electric auxiliary pump Checking The Electric Auxiliary Pump
- Ignition on
- Listen to the electronic additional pump or vacuum pump.
The pump must start and run for a few seconds.
Does the pump start?
Yes - Checking the vacuum line and the vacuum pump
No - Checking the cable
-------------------------------------------------
Checking the cable
- Ignition off.
Check the fuses for the vacuum pump in the integrated relay/fusebox in the engine compartment. If the fuse is blown, check the circuit after the fuse for a short-circuit to ground and an open-circuit.
Check the cable between the system relay and vacuum control valve terminal #1. Check the cable between vacuum control valve terminal #2 and pump relay base terminal #1. Check for an open-circuit. Check the cable between pump relay base terminal #2 and the ground terminal. Check for an open-circuit.
Check the ground lead between vacuum pump terminal #2 (cable harness side) and ground. Check for an open-circuit. Check the ground terminal for contact resistance and oxidation.
Other information:
- To access and replace the vacuum pump, see Removing and installing the electronic accessory pump assembly Removing And Installing The Electronic Accessory Pump Assembly
- To fault-trace wiring and terminals see Checking wiring and terminals. Permanent fault Checking Wiring And Terminals. Permanent Fault
- To access or replace the fuse, see the inside of the relay and integrated relay/fusebox cover or the wiring diagram.
Was a fault detected?
Yes - Verification
No - Checking the component
-------------------------------------------------
Checking the component
- Brake several times to diminish the vacuum
- Ignition on.
Check the regulator valve by measuring the voltage at pump relay base terminal #1 in the integrated relay/fusebox in the engine compartment. The pressure sensor is closed if there is no vacuum. The voltage must be approximately 12 V.
Try a new control valve if there is no voltage.
Take voltage readings between terminals #1 and #2 on the vacuum pump connector (cable harness side).
Try a new vacuum pump if the voltage is approximately 12 V.
Try a new relay if the voltage is 0 V.
Note! The voltage can only be read off for a few seconds after ignition on before the system relay switches off. Brake repeatedly and switch the ignition on before taking each reading.
Other information:
- To access or replace the vacuum pump and control valve, see
Continue - Verification
-------------------------------------------------
Checking the vacuum line and the vacuum pump
- Ignition off.
Check the vacuum lines and the connections between the control valve / brake booster and the vacuum pump. Check for leakage.
Check that the vacuum pump is providing a sufficient vacuum. See Checking the electric auxiliary pump Checking The Electric Auxiliary Pump.
Other information:
- To access and replace the vacuum control valve, see Replacing the vacuum control valve Replacing Vacuum Control Valve.
Reconnect separated components. Select "Continue".
Continue - Verification
-------------------------------------------------
Verification
Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Brake several times to diminish the vacuum
- Ignition on
- Listen to the vacuum pump.
The vacuum pump must start and run for a few seconds.
Note! When the ignition is on and the vacuum is low enough, the electronic vacuum pump starts. The pump only runs for a few seconds because the system relay switches off.
Is the function correct?
Yes - VERIFIED
No - VERIFICATION FAILED
------------------------
VERIFICATION FAILED - Fault-tracing information
VERIFIED - FAULT FOUND
-------------------------------------------------
Fault-tracing information
Information
Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.
Do you want to exit fault-tracing?
Yes - FAULT-TRACING FAILED
No - Attempt New Test
------------------------
Attempt New Test - Checking the electronic additional pump / vacuum pump
FAULT-TRACING FAILED - FAULT-TRACING FAILED
-------------------------------------------------