PCM Inputs That Affect the 4T40-E Transmission

PCM INPUTS THAT AFFECT THE 4T40-E TRANSMISSION
Throttle Position Sensor
- Provides throttle position data to the Powertrain Control Module (PCM) for determining shift patterns and Torque Converter Clutch (TCC) apply/release.
- An incorrect throttle position sensor input could cause erratic or shift pattern, poor shift quality or TCC function.

Automatic Transmission Vehicle Speed Sensor
- Provides vehicle speed data to the PCM for determining shift patterns, TCC apply/release, and gear ratio calculations.
- An incorrect Automatic Transmission Vehicle Speed Sensor (A/T VSS) input could cause erratic or shift pattern, poor shift quality or TCC function.

Automatic Transmission Input (Shaft) Speed Sensor
- Provides transaxle input speed data to the PCM for controlling line pressure, shift patterns, TCC apply and release and calculating gear ratio.

Engine Coolant Temperature Sensor
- Provides coolant temperature data to the PCM for determining initial TCC engagement.
- An incorrect engine coolant temperature sensor input could cause an incorrect initial TCC apply.

Cruise Control
- When engaged, the PCM alters the transaxle shift pattern to reduce the number of 3-4 upshifts and 4-3 downshifts. The PCM also alters TCC apply and release.

Engine Speed
- The ignition module provides engine speed data to the PCM.
- The PCM uses engine speed information for controlling Wide Open Throttle (WOT) shifts and the TCC Pulse Width Modulated (PWM) solenoid duty cycle.

Brake Switch
- Provides brake apply information to the PCM for controlling TCC apply and release.
- An incorrect TCC brake switch input could cause an incorrect TCC apply or release.

Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.)
- Provides transaxle shift linkage position information to the PCM for determining transaxle range and shift patterns.
- An incorrect Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP val. position sw.) input could cause incorrect shift points, poor shift quality, incorrect or inhibited TCC apply, incorrect line pressure, or erratic manual downshifts.

Transmission Fluid Temperature (TFT) Sensor
- Provides Transaxle Fluid Temperature (TFT) information to the PCM for determining alternate shift patterns and TCC apply during high temperature conditions (hot mode operation).
- An incorrect transaxle temperature sensor input could cause altered shift patterns, poor shift quality and incorrect TCC apply.

Manifold Absolute Pressure Sensor
- Measures intake manifold pressure which results from changes in engine load and speed. The PCM monitors this information to adjust line pressure and shift patterns.
- An incorrect Manifold Absolute Pressure (MAP) sensor input could cause altered shift patterns, shift feel and TCC apply.