GxT Ferret 91 2-Channel Labscope - Manual (Page 8)

8
Sensor Tests
ABS Wheel Speed
Connect COM probe to the sensor “low”, “-”, or ground
circuit. Connect CH1 probe to the sensor “high”, “+” or
signal output to the ABS control unit. Spin the wheel and
look for symmetrical oscillations that increase in amplitude
as wheel speed increases.
Oxygen Sensor 1V
Connect COM probe to the O2 sensor ground circuit or
sensor body (NOT the negative battery terminal). Connect
the CH1 probe to the O2 sensor signal wire to the PCM.
Warm the engine for 2-3 minutes at 2500 RPM. Test the
sensor using propane enrichment or “snap-throttle”
method. Check for proper max/min voltage and response
time.
Oxygen Sensor 5V
Connect COM probe to the O2 sensor ground circuit or
sensor body (NOT the negative battery terminal). Connect
the CH1 probe to the O2 sensor signal wire to the PCM.
Warm the engine for 2-3 minutes at 2500 RPM. Test the
sensor using propane enrichment or “snap-throttle”
method. Check for proper max/min voltage and response
time.
O2 Sensor Dual 1V
Connect COM probe to the O2 sensors’ ground circuit or
sensor body (NOT the neg. battery terminal). Connect
the CH1 probe to the #1 (Pre-Cat) O2 sensor signal to
the PCM. Connect the CH2 probe to the #2 (Post-Cat)
O2 sensor signal to the PCM. Warm the engine for 2-3
minutes at 2500 RPM. Test the sensors using propane
enrichment or “snap-throttle” method. Check for proper
max/min voltage and response time.