General Technologies ST05 Oxygen Sensor Tester and Simulator - Manual (Page 5)

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3.5 Oxygen sensor response test
1- Select the sensor type to test and connect the test leads following the steps described
in “3.4.1 Setting the type of sensor” and “3.4.2 Sensor signal measurement”
2- Make sure that the engine and the oxygen sensor are at normal operating temperature,
by running the engine at around 2500 RPM for 3 minutes
3- Insure the engine is running at approximately 2500 RPM, and press the (TEST)
button once, the alphanumeric display will flash for approximately 20 seconds.
During this period the instrument will continuously monitor the sensor response.
4- While the display is still flashing , release the throttle and wait for the bargraph to
show a lean signal, then snap the throttle and release. You may repeat this procedure
at 2 to 3 seconds intervals while still in test mode.
5- The result will be shown on the alphanumeric display :
PASS
A sensor signal response time from < 175 mV to > 800 mV in less than 100 ms,
will end the test automatically, and the display will show the sensor passed the
response test.
FAIL
If the signal does not cross both the 175 mV and 800 mV thresholds, or if it takes
longer than 100 ms to do so, the test will continue for the entire 20 seconds, and
the display will show the sensor failed the response time test.
•
This test can be ended at any time by pressing the (Test) button again.
3.6 Oxygen sensor simulation
1- Select the sensor type to test and connect the test leads following the steps described
in “3.4.1 Setting the type of sensor” and “3.4.2 Sensor signal measurement”
Simulate Rich
To simulate a rich fuel mixture condition for the Powertrain Control Module (PCM),
press the (Rich) button once, the alphanumeric display will then show
flashing during the simulation period.
Simulate Lean
To simulate a lean fuel mixture condition for the PCM, press the (Lean) but-
ton once, the alphanumeric display will then show flashing during the
simulation period.
•
If when pressing either of the simulation buttons, the alphanumeric display shows a
flashing (Low battery) code, it indicates that the battery is too low to operate this
function, and should be replaced.
• The simulation times are limited to 4 seconds maximum, and there is a time delay of 4
seconds before the instrument is able to repeat the same simulation. These time limits are
safety features designed to avoid damage to the engine and/or catalytic converter.
•
The simulation can be ended at any time by pressing the button corresponding to
the simulation in progress, or it can be switched from Lean to Rich or from Rich to
Lean at any time.
3.7 Additional Functions
3.7.1 Accessing Demo mode
Demo mode
This mode is intended to show how the instrument works, without the need to be
connected to an actual oxygen sensor or any external signal. Upon entering this
mode the bargraph and the alphanumeric display will show a simulated measure-
ment of a working oxygen sensor. It also allows you to change the sensor type,
test for response time and to use the simulate rich and lean functions.
1- To enable this function, the instrument should be off, if is not, turn it off by pressing
and holding the Power ON/OFF button until the displays turn off.
2- Press and hold the (Test) button, then turn the instrument on by pressing the Power
ON/OFF button until the alphanumeric and bargraph displays turn on, while still
pressing the Test button.
3- When entering the demo mode, the alphanumeric display will momentarily show
and then displays the simulated signal.
4- While in the demo mode, you may demo all the functions of the ST05.
5- To exit the Demo Mode, turn off the unit by pressing and holding the Power ON/OFF
button until the displays turn off.
3.7.2 Error and warning codes
Heater wire
The instrument test leads are connected to a heater wire(s) or a circuit with more
than 6 Vdc. To correct this error, attach the test leads to the signal and ground
wire of the oxygen sensor (Fig. 3).
Overload current
Overload current was detected when trying to simulate a Rich or Lean condi-
tions. This condition will not damage the instrument. It could be caused by incor-
rect connections of the test leads, faulty oxygen sensor or wiring, or by a sensor
with an impedance (resistance) below the minimum allowed by the instrument.
Reverse polarity
Test leads connected with reverse polarity. Reconnect test leads observing the
polarity: red clip -> signal wire, black clip -> ground or common (Fig. 3).
Open connection
Test leads are not connected, the connection is not good or the sensor
wiring is faulty.
Ground
The red clip (Signal) is connected to ground. This error could be caused by
a connection to the wrong (ground) wire, or by a faulty (short circuit) oxygen
sensor or wiring.