Function
| Enable Parameter
| Result
or Use
|
EGO Ready Timer (EGO Warm Criteria
|
| • | RT Counts @ 3052 or approx. 100 seconds |
|
| • | When the EGO ready timer reacher 3052 counts or approximately
100 seconds, any diagnostic dependent on a warm EGO sensor will be
enabled. |
| • | The ready timer will stop counting up at 3662 counts or
approximately 120 seconds. |
| • | When M Gas drops below 0.35 g/s, the ready timer will count
backwards so as to disable any diagnostics that may fail due to a possible
cold O2S during extended idle periods. |
|
Decel Fuel Cut-Off (DFCO)
|
|
| • | The catalyst temperatures may exceed maximum limits during extended
decel maneuvers. |
| • | When the criteria is met, the low pressure lock-off will be
cycled off to shut off all fuel and cool the catalysts. |
| • | DFCO turns off the LPL until mode is exited. |
|
Decel Fuel Open Loop
|
|
| • | The vehicle will operate in open loop as soon as a deceleration
is detected that meets the criteria. |
| • | The vehicle will transition into DFCO if this decel time reaches
8 seconds. |
|
Speed Limiting
| VSS > 107 mph
|
| • | Speed limiting is achieved by closing the MCV valve at 107 mph
and does not reopen until 104 mph. |
| • | The vehicle operates in open loop while in speed limiting. |
|
RPM Limiting (In drive > 10 mph)
| RPM > 6000
|
| • | RPM limiting is achieved by closing the MCV valve at 6000 RPM
and does not reopen until 5800 RPM. |
| • | The vehicle operates in open loop while in RPM limiting. |
|
RPM Limiting (In neutral or below 10 mph)
| RPM > 4000
|
| • | RPM limiting is achieved by closing the MCV valve at 4000 RPM
and does not reopen until 3900 RPM. |
| • | The vehicle operates in open loop while in RPM limiting. |
|
Fuel Switch-Over
|
| • | FPS Voltage < 0.85 Volt |
| • | Wide Open MCV (< 4100 RPM and 1.0 second
at WOT, 100 ms at idle or 2 seconds at crank) |
|
| • | The vehicle will switch over to gasoline if an OBD fault is detected,
if crank time exceeds eight seconds, or if a wide open MCV is detected for
the amount of time noted. |
| • | The FPS will cause a switch-over if voltage (indicating fuel
level) drops below 0.85 volt (2 412 kPa at 21°C
[350 psi at 70°F]). |
| • | The vehicle will not restart on CNG until voltage exceeds 1.5 volts
(6 890 kPa at 21°C [1000 psi at 70°F]). |
|
Open Loop
|
| • | OBD failure of both O2 sensors |
|
| • | Block Learn and EGO multiplier will both be disabled, and EGO
multiplier will be returned to 1.000. |
| • | Fueling will be based on the block learn table as it exists prior
to going open loop. |
|
Closed Loop
|
|
| • | For the vehicle to enter closed loop operation, the ECU looks
at the ECT at start-up and will hold off closed loop operation for 18-92
seconds, depending on temperature. |
| • | In addition to ECT time, the ECU will look for an O2 sensor
switch and add an additional 7-35 seconds, depending on O2 activity. |
|
Lock-Offs
|
|
| • | The ECU will open the HPL for 1 second after a complete shutdown
and a key-on sequence. |
| • | After a 25 RPM signal is received, the LPL and the HPL
will be opened as long as an RPM signal is present. |
|
Gasoline Starts or Cold Start Strategy
| -12°C (10°F) or every 100 starts
Will switch to CNG operation when the criteria below is met.
|
| • | Gasoline start strategy used for gasoline injector durability. |
| • | On gasoline start codes 41, 58, 66 and 67 run while in gasoline
operation. All others are delayed until five seconds after switch-over occurs. |
| | TPS > 6% during 500 ms switch-over period. |
|
Code Types
| --
|
| • | Type A: Emissions related. One cycle to set the MIL and DTC. |
| • | Type B: Emissions related. Two consecutive driving cycles to set
the MIL and DTC. |
| • | Type C: NOT USED. Non-emission related. No MIL , but the SES
light will turn on. |
| • | Type D: Non-emission related. No MIL or SES light set. |
|
