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ManualsBrandsLAUNCH ManualsAutomotiveCRP909C Automotive Diagnostic Scanner with 7'' Touch Screen, All Systems OBD2 Scanner Auto Scan Tool Car Code Reader Including 15 Service Functions Oil Reset, ABS, SRS, EPB, SAS, etc
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Professional 909 User Manual
This Monitor uses a Fuel System Correction program, called Fuel Trim, inside
the on-board computer. Fuel Trim is a set of positive and negative values that
represent adding or subtracting fuel from the engine. This program is used
to correct for a lean (too much air/not enough fuel) or rich (too much fuel/not
enough air) air-fuel mixture. The program is designed to add or subtract fuel,
as needed, up to a certain percent. If the correction needed is too large and
exceeds the time and percent allowed by the program, a fault is indicated by the
computer.
The Fuel System Monitor is supported by both “spark ignition” vehicles and
“compression ignition” vehicles. The Fuel System Monitor may be a “One-Trip”
or “Two-Trip” Monitor, depending on the severity of the problem.
3. Comprehensive Components Monitor (CCM)
This Monitor continuously checks all inputs and outputs from sensors, actuators,
switches and other devices that provide a signal to the computer. The Monitor
checks for shorts, opens, out of range value, functionality and “rationality* (
See
Note
).”
Raonality: Each input signal is compared against all other inputs and against
informaon in the computer’s memory to see if it makes sense under the current
operang condions.
Example: The signal from the throttle position sensor indicates the vehicle is
in a wide-open throttle condition, but the vehicle is really at idle, and the idle
condion is conrmed by the signals from all other sensors. Based on the input
data, the computer determines that the signal from the throle posion sensor
is not raonal (does not make sense when compared to the other inputs). In this
case, the signal would fail the raonality test.
The CCM is supported by both “spark ignition” vehicles and “compression
ignition” vehicles. The CCM may be either a “One-Trip” or a “Two-Trip” Monitor,
depending on the component.
2.6.2 Non-Continuous Monitors
The other twelve Monitors are “non-continuous” Monitors. “Non-continuous”
Monitors perform and complete their testing once per trip. The “non-continuous”
Monitors are:
1. O2 Sensor Monitor
The Oxygen Sensor monitors how much oxygen is in the vehicle’s exhaust. It
generates a varying voltage of up to one volt, based on how much oxygen is in
the exhaust gas, and sends the signal to the computer. The computer uses this