6E2–58
6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS
Exhaust Gas Recirculation (EGR)
Diagnosis
Pintle position error diagnosis is covered by DTC P0402,
P0404, P1404, P0405, P0406. If EGR diagnostic trouble
codes P0402, P0404, P1404, P0405, P0406 are
encountered, refer to the DTC charts.
Engine Tech 2 Data Definitions and
Ranges
A/C CLUTCH–Tech 2 Displays ON or OFF–
Indicates whether the PCM has commanded the A/C
clutch ON. Used in A/C system diagnostic.
A/C REQUEST — Tech 2 Displays YES or NO —
Indicates the state of the A/C request input circuit from the
HVAC controls. The PCM uses the A/C request signal to
determine whether A/C compressor operation is being
requested.
AIR/FUEL RATIO — Tech 2 Range 0.0-25.5 —
Air/fuel ratio indicates the PCM commanded value. In
closed loop, the air/fuel ratio should normally be
displayed around “14.2–14.7.” A lower air/fuel ratio
indicates a richer commanded mixture, which may be
seen during power enrichment or TWC protection modes.
A higher air/fuel ratio indicates a leaner commanded
mixture. This can be seen during deceleration fuel mode.
BARO kPa — Tech 2 Range 10-105 kPa/0.00-5.00
Volts —
The barometric pressure reading is determined from the
MAP sensor signal monitored during key up and wide
open throttle (WOT) conditions. The barometric pressure
is used to compensate for altitude differences and is
normally displayed around “61-104” depending on
altitude and barometric pressure.
CHECK TRANS LAMP–AUTO TRANSMISSION–
Indicates the need to check for a DTC with the Tech 2
when the lamp is flashing 0.2 seconds ON and 0.2
seconds OFF.
CMP ACT. COUNTER –Cam Position
ActivityDECEL FUEL MODE—Tech 2 Display
ACTIVE or INACTVE—
“ACTIVE” displayed indicates that the PCM has detected
conditions appropriate to operate in deceleration fuel
mode. The PCM will command the deceleration fuel
mode when it detects a closed throttle position while the
vehicle is traveling over 20 mph. While in the decreasing
fuel mode, the PCM will decrease the amount of fuel
delivered by entering open loop and decreasing the
injector pulse width.
DESIRED EGR POS.—Tech 2 Range 0%-100%—
Represents the EGR pintle position that the PCM is
commanding.
DESIRED IDLE — Tech 2 Range 0-3187 RPM —
The idle speed that the PCM is commanding. The PCM
will compensate for various engine loads based on engine
coolant temperature, to keep the engine at the desired
speed.
ECT — (Engine Coolant Temperature) Tech 2
Range –40
°
C to 151
°
C (–40
°
F to 304
°
F) —
The engine coolant temperature (ECT) is mounted in the
coolant stream and sends engine temperature
information to the PCM. The PCM applies 5 volts to the
ECT sensor circuit. The sensor is a thermistor which
changes internal resistance as temperature changes.
When the sensor is cold (high resistance), the PCM
monitors a high signal voltage and interprets that as a cold
engine. As the sensor warms (decreasing resistance),
the voltage signal will decrease and the PCM will interpret
the lower voltage as a warm engine.
EGR DUTY CYCLE — Tech 2 Range 0%-100% —
Represents the EGR valve driver PWM signal from the
PCM. A duty cycle of 0% indicates that no EGR flow is
being commanded; a 100% duty cycle indicates
maximum EGR flow commanded.
EGR FEEDBACK — Tech 2 Range 0.00-5.00 Volts —
Indicates the EGR pintle position sensor signal voltage
being monitored by the PCM. A low voltage indicates a
fully extended pintle (closed valve); a voltage near 5 volts
indicates a retracted pintle (open valve).
ENGINE LOAD — Tech 2 Range 0%-100% —
Engine load is calculated by the PCM from engine speed
and MAF sensor readings. Engine load should increase
with an increase in RPM or air flow.
ENGINE RUN TIME — Tech 2 Range
00:00:00-99:99:99 Hrs:Min:Sec —
Indicates the time elapsed since the engine was started.
If the engine is stopped, engine run time will be reset to
00:00:00.
ENGINE SPEED — Range 0-9999 RPM —
Engine speed is computed by the PCM from the 58X
reference input. It should remain close to desired idle
under various engine loads with engine idling.
EVAP PURGE PWM — Tech 2 Range 0%-100% —
Represents the PCM commanded PWM duty cycle of the
EVAP purge solenoid valve. “0%” displayed indicates no
purge; “100%” displayed indicates full purge.
EVAP VENT VALVE– Tech 2 Displays PURGE or
NO PURGE–
The EVAP purge vacuum valve is a normally closed valve
positioned in the purge line between the canister and the
EVAP purge solenoid. The EVAP purge vacuum valve
will open when vacuum increases to greater than 5 inches
of water in the purge line. The EVAP purge vacuum valve
is used by the PCM to monitor EVAP canister purge
solenoid opetation and purge system integrity. The EVAP
purge vacuum valve should be closed to ground with no
vacuum present (0% EVAP purge PWM). With EVAP
purge PWM at 25% or greater, the EVAP purge vacuum
valve should be open and “PURGE” should be indicated.
FUEL TRIM CELL — Tech 2 Range 0-21 —
The fuel trim cell is dependent upon engine speed and
MAF sensor readings. A plot of RPM vs. MAF is divided
into 22 cells. Fuel trim cell indicates which cell is currently
active.