Transmission and Cruise Control Parameters

TRANSMISSION AND CRUISE CONTROL PARAMETERS

NOTE:
These parameters indicate logic module commands to, and signals from, various actuators and sensors in the transmission and the cruise control system.


SHIFT INDICATOR LAMP

SHIFT IND LAMP - XXX RANGE: ON - OFF

This parameter is displayed on some 1989 and later trucks with manual transmissions. It is an output command from the logic module to the instrument panel lamp. The logic module determines whether the lamp should light based on engine and vehicle speeds and engine load. SHIFT IND LAMP ON means that the SHIFT lamp on the panel should be lit. If it is not, there is a problem in the lamp circuit or with the logic module command.


AUTOMATIC TRANSMISSION OVERDRIVE SOLENOID

OVERDRIVE SOL - XXX RANGE: ON - OFF

This discrete parameter on 1989 and later rear-wheel drive trucks, indicates that the logic module has energized the overdrive solenoid for the automatic overdrive transmission. OVERDRIVE SOL will be YES when all requirements are met to allow overdrive engagement, NO when they are not. This parameter indicates that the logic module command has been given. It is not a feedback signal to indicate that overdrive has actually engaged.


SHIFT LEVER POSITION

SHIFT LEVER - XXXXX RANGE: P-N-/-R-D-L

On 1989 and later vehicles, the park/neutral switch provides a discrete parameter that indicates whether an automatic transmission is in park or neutral or in one of the drive ranges. The SHIFT LEVER display should read P-N- if the transmission is in either park or neutral. It should read -R-DL if the transmission is in any forward gear or reverse.



TORQUE CONVERTER LOCK-UP SOLENOID

LOCKUP SOL - XXX RANGE: ON - OFF

This discrete parameter on some 1989 and later vehicles indicates that the logic module has enabled the torque converter lockup clutch to engage. Torque converter lockup depends on gear selection, speed, engine temperature, and throttle position. LOCKUP SOL ___ON means that the logic module has completed one side of the circuit that energizes the solenoid.

The circuit also must be completed by various transmission, speed, and brake switches to open the transmission hydraulic line and engage the lockup clutch. This parameter indicates that the logic module command has been given. It is not a feedback signal to indicate that the clutch has actually engaged.


CRUISE CONTROL SWITCH POSITION

CRUISE CNTRL - XXXXX RANGE: ON - OFF - SET - RESUME

This discrete parameter on 1989 and later vehicles indicates the position of the cruise control switch to the logic module. Vehicles without cruise control continuously display this parameter as OFF.


CRUISE CONTROL TARGET SPEED

CC TARGET (MPH) - XXX
RANGE: 0 to VEHICLE MAXIMUM
CC TARGET (KPH) - XXX

This parameter on some 1990 and later vehicles indicates the speed at which the cruise control is set by the driver. You can change the measurement units on the scanner from MPH to KPH. the preset value is MPH.


CRUISE CONTROL STATUS INDICATORS

CC LAMP - XXX
RANGE: ON - OFF
CC POWER RELAY - XXX

CC LAMP indicates the status of the signal to the cruise control lamp. CC POWER RELAY indicates the status of the signal to the relay that provides battery voltage to the speed control servo solenoids. Both parameters should read ON when cruise control is enabled.


CRUISE CONTROL SWITCH INPUT

CC SW INPUT(V) - X.X RANGE: 0 to 5.1 volts

This parameter displays the cruise control switch analog voltage.



BRAKE SWITCH

BRAKE - XXX RANGE: ON - OFF

On 1989 vehicles, the brake switch used with cruise control (CC) provides an input signal to the logic module. The brake switch contacts that signal the logic module for cruise control and torque converter clutch operation are normally closed. When the brake pedal is depressed, the logic module receives a high-voltage, open-circuit signal and disengages the cruise control. BRAKE should read ON when the brake pedal is depressed; OFF at all other times.



CRUISE CONTROL SOLENOIDS

CC VAC SOL - xxxx
RANGE: OPEN - CLAST
CC VENT SOL - xxxx

On 1989 and later vehicles, the logic module sends output commands to the cruise control (CC) vacuum and vent solenoids to control the cruise control servo. The CC VAC SOL and CC VENT SOL readings should read ON whenever the solenoids are energized to increase or to vent vacuum.

The CC VAC SOL and CC VENT SOL readings usually have the following relationships with throttle position control:

CC VAC SOL CC VENT SOL THROTTLE POSITION

ON OFF Accelerate

ON or OFF ON Decelerate

OFF OFF Steady