3500 4x4 Pickup L6-359 5.9L DSL Turbo (1996)
Powertrain Control Module: Description and Operation
Battery Feed
CIRCUIT OPERATION
Circuit A14 from fuse 8 in the Power Distribution Center (PDC) supplies battery voltage to cavity A22 of the Powertrain Control Module (PCM).
Ground
CIRCUIT OPERATION
Circuit Z12 connects to cavities A31 and A32 of the Powertrain Control Module (PCM). The Z12 circuit provides ground for PCM internal
drivers that operate high current devices like the injectors and ignition coil.
Acceleration Mode
ACCELERATION MODE
When there is an abrupt demand for increased engine output and vehicle acceleration, the following occurs:
1. The vehicle speed, crank position, and throttle position sensors are used to control transmission overdrive and torque converter clutch
operation.
2. If the transmission temperature sensor determines it is below 69°F, the transmission's torque converter clutch will not be allowed to engage.
3. If the transmission temperature sensor determines it is below 59°F or above 275°F, the automatic transmission will not be allowed to enter
overdrive. If the transmission is in overdrive when the transmission temperature is above 275°F, the transmission will downshift and not
upshift again until the transmission temperature drops to 240°F.
4. If the speed control system resume/accelerate function is being used, the Powertrain Control Module (PCM) will only allow the vehicle to
accelerate at a predetermined rate. If a speed control has been set and the resume/accelerate button is momentarily pushed in, the PCM will
increase vehicle speed by two miles per hour.
5. The PCM will disable the speed control when:
-
the brakes are applied
-
the clutch is disengaged (manual transmission)
-
the gear selector is shifted to neutral (automatic transmission)
-
the speed control off switch is activated
Cruise or Idle Mode
CRUISE OR IDLE MODE
During cruising speed, the following inputs are received by the Powertrain Control Module (PCM):
1. The PCM monitors intake manifold air temperature through the intake air temperature sensor.
2. The intake air heater post-heat cycle will be completed, if it is not already over.
3. The vehicle speed, crank position, and throttle position sensors are used to control the transmission overdrive and torque converter clutch
operation.
4. If the transmission temperature sensor determines it is below 59°F or above 275°F, the automatic transmission will not be allowed to enter
overdrive. If the transmission is in overdrive when the transmission temperature is above 275°F, the transmission will downshift and not
upshift again until the transmission temperature drops to 240°F.
5. The water in-fuel sensor signal is used by the PCM to turn on the water-in-fuel lamp, if water is sensed in the fuel.
Deceleration Mode
DECELERATION MODE
During deceleration, the following inputs are received by the Powertrain Control Module (PCM):
1. The vehicle speed, crank position, and throttle position sensors are used to control transmission overdrive and torque converter clutch operation.
2. The torque converter clutch will disengage, if the brakes are applied.
3. If the transmission temperature sensor determines it is below 59°F or above 275°F, the automatic transmission will not be allowed to enter
overdrive. If the transmission is in overdrive when the transmission temperature is above 275°F, the transmission will downshift and not upshift
again until the transmission temperature drops to 240°F.
4. The PCM will disable the speed control when:
-
the brakes are applied
-
the clutch is disengaged (manual transmission)
-
the gear selector is shifted to neutral (automatic transmission)
