SP01501467 | REV A | 4.2021
Bosch Automotive Service Solutions Inc
SMT500 Leak Detector
| Operating Instructions |
7
|
en
Verify Repairs
PERFORM DECAY / LEAK DOWN TEST
1. Pressurize the sealed system.
2.
Lock out system by turning flow control knob
clockwise to the fully closed position.
OBSERVE PRESSURE GAUGE FOR DECAY
Pressure
holds
No leaks; repair complete
Pressure
decreases
Leak(s) exist; repair
necessary
NOTE: Not all systems are designed to be 100%
sealed.
Diagnostics
Intake System and Vacuum Leaks
This procedure will locate leaks in vacuum lines
as well as manifolds, EGR valves, oil seals,
gaskets, solenoids, o-rings, ducting, throttle
shafts, diaphragms, canisters, and more.
Note: For best results, test in a draft-free area.
1.
Remove the air filter housing from ducting.
2. If the vehicle has a round inlet tube from the
air filter, place the cone adapter into the duct
toward the engine.
3. Put the vapor supply hose into cone adapter
to introduce vapor into the system.
4. Use daylight spectrum LED cordless light to
locate leaks.
Alternative method:
1. Select an appropriate vacuum line to access
the vacuum system (i.e. a brake booster
supply line before the check valve).
2. Seal all system openings.
• Air Intake must be sealed to prevent vapor
from leaking back through the intake.
• To seal the intake, use cap plugs, a latex
glove, or plastic wrap around the filter.
3. Put vapor output hose into cone adapter to
introduce vapor into the system.
4. Use daylight spectrum LED cordless light to
locate leaks.
EVAP Leaks
Leaks in the EVAP system, or fuel vapor recovery
system, are frequently the cause for check
engine lights. Using a diagnostic leak detector,
these leaks can now be quickly diagnosed and
repaired, making them profitable services for
repair facilities.
1. To access the EVAP service port, remove the
green cap.
2. Remove Schrader valve using the Schrader
valve removal tool.
Note: Schrader valve has left-handed threads;
turn clockwise to remove.
3. Connect the EVAP service port adapter to
the service port.
4. Use a scan tool to close the vent solenoid
to close EVAP system from atmosphere. (If
vent solenoid does not close, intermittent
solenoid may have failed.)
