6E–49
3.2L ENGINE DRIVEABILITY AND EMISSIONS
INJ. PULSE BANK 1 – Tech 2 Range 0-1000 msec. –
Indicates the amount of time the ECM is commanding
each injector “ON” during each engine cycle. A longer
injector pulse width will cause more fuel to be delivered.
Injector pulse width should increase with increased
engine load.
LONG TERM FUEL TRIM BANK 1
The long term fuel trim is derived from the short term fuel
trim values and represents a long term correction of fuel
delivery for the bank in question. A value of 0% indicates
that fuel delivery requires no compensation to maintain
the ECM commanded air/fuel ratio. A negative value
significantly below 0% indicates that the fuel system is
rich and fuel delivery is being reduced (decreased injector
pulse width). A positive value significantly greater than
0% indicates that a lean condition exists and the ECM is
compensating by adding fuel (increased injector pulse
width). Because long term fuel trim tends to follow short
term fuel trim, a value in the negative range due to
canister purge at idle should not be considered unusual.
Fuel trim values at maximum authority may indicate an
excessively rich or lean system.
MAF — Tech 2 Range 0.0-512 g/s —
MAF (mass air flow) is the MAF input frequency
converted to grams of air per second. This indicates the
amount of air entering the engine.
MIL — Tech 2 Displays ON or OFF —
Indicates the ECM commanded state of the malfunction
indicator lamp.
POWER ENRICHMENT — Tech 2 Displays ACTIVE
or INACTIVE —
“ACTIVE” displayed indicates that the ECM has detected
conditions appropriate to operate in power enrichment
mode. The ECM will command power enrichment mode
when a large increase in throttle position and load is
detected. While in power enrichment mode, the ECM will
increase the amount of fuel delivered by entering open
loop and increasing the injector pulse width. This is done
to prevent a possible sag or hesitation from occurring
during acceleration.
SPARK — Tech 2 Range –64
°
to 64
°
—
Displays the amount of spark advance being commanded
by the ECM on the IC circuit.
START-UP ECT — Tech 2 Range –40
°
C to 151
°
C
(–40
°
F to 304
°
F) —
Indicates the engine coolant temperature at the time that
the vehicle was started. Used by the HO2S diagnostic to
determine if the last start-up was a cold start.
TP — Tech 2 Range 0%-100% —
TP (throttle position) angle is computed by the ECM from
the TP sensor voltage. TP angle should display “0%” at
idle and “100%” at wide open throttle.
TP SENSOR — Tech 2 Range 0.00-5.00 Volts —
The voltage being monitored by the ECM on the TP
sensor signal circuit.
CATALYST PROTECTION MODE— Tech 2 Displays
YES or NO —
“YES” displayed indicates that the ECM has detected
conditions appropriate to operate in TWC protection
mode. The ECM will decrease the air/fuel ratio to a value
that depends on mass air flow (higher mass air flow =
lower air/fuel ratio).
WEAK CYLINDER –Tech 2 Displays Cylinder
Number—
This indicates that the ECM has detected crankshaft
speed variations that indicate 2% or more cylinder firing
events are misfires.
Typical Scan Data Values
Use the Typical Scan Data Values Table only after the
On-Board Diagnostic System Check has been
completed, no DTC(s) were noted, and you have
determined that the on-board diagnostics are functioning
properly. Tech 2 values from a properly-running engine
may be used for comparison with the engine you are
diagnosing. The typical scan data values represent
values that would be seen on a normally-running engine.
NOTE: A Tech 2 that displays faulty data should not be
used, and the problem should be reported to the Tech 2
manufacturer. Use of a faulty Tech 2 can result in
misdiagnosis and unnecessary replacement of parts.
Only the parameters listed below are referred to in this
service manual for use in diagnosis. For further
information on using the Tech 2 to diagnose the ECM and
related sensors, refer to the applicable reference section
listed below. If all values are within the typical range
described below, refer to the
Symptoms section for
diagnosis.
Test Conditions
Engine running, lower radiator hose hot, transmission in
park or neutral, closed loop, accessaries off, brake not
applied and air conditioning off.