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 PCM for determining shift patterns and 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 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 shifts and the TCC 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 Transaxle Range (TR) Selection Switch
- Provides transaxle shift linkage position information to the PCM for determining transaxle range and shift patterns.
- An incorrect TR switch 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 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 MAP sensor input could cause altered shift patterns, shift feel and TCC apply.