Skip Shift Description and Operation (MM6)
The skip shift solenoid is a performance feature which forces the driver to shift from first gear to fourth gear during light acceleration and low engine load conditions. This feature is used to ensure good fuel economy and compliance with federal economy standards. The skip shift system consist of the following components:
- The engine control module (ECM).
- The skip shift solenoid.
- Message in the message center.
With the ignition ON, battery voltage is supplied directly to the skip shift solenoid. The engine control module (ECM) controls the solenoid by grounding the control circuit. When the skip shift system is active the ECM also grounds the control circuit of the skip shift lamp. The message illuminates to inform the driver that the 1 - 4 skip shift is engaged. The ECM determines when the skip shift system is active when the following parameters are met:
- The vehicle speed is between 24 - 30 km/h (15 - 19 mph).
- The engine coolant temperature (ECT) is greater than 77°C (171°F).
- The BARO is greater than 76 kPa.
- The accelerator pedal position (APP) is less than 13 percent.
When the conditions are met the engine control module (ECM) grounds the skip shift solenoid control circuit. This energizes the skip shift solenoid and mechanically blocks the gear shift lever from going into the second or third gear positions. When the drivers pulls back on the shift lever with the system enabled the transmission will go into fourth gear.
When the conditions for skip shift engagement are no longer met the engine control module (ECM) disables the skip shift solenoid, allowing the driver to use second and third gears.
Once the skip shift solenoid is enabled the system will not be re-enabled until the vehicle speed returns to 0 km/h (0 mph) and the conditions for enabling skip shift solenoid are met.