Modes of Operation

In this mode, the Logic Module or SMEC compensates for the failure of certain components by suibstituting information from other sources. If the Logic Module or SMEC senses incorrect data at all from the MAP Sensor, Throttle Position Sensor, Charge Temperature Sensor, Coolant Temperature Sensor or Battery Voltage Sensor, the system is placed into Limp In Mode and the Power Loss/Check Engine Lamp on instrument panel is activated.








The following is a description of each "limp-in" mode:

1. M.A.P. (Manifold Absolute Pressure) Sensor. If this signal is either too low, (less than .3 volts) too high, (greater than 4.9 volts) or not changing fault codes 13 and/or 14 are recorded in memory and the "power loss" lamp is turned "ON". At this time the throttle position and engine speed signals are used by the logic module to generate a modified M.A.P. sensor signal in place of the failed one. While in this "limp-in" mode the automatic idle speed motor is driven to its minimum position.
2. Throttle Position Sensor. If this signal is either too low (less than .16 volts) or too high (greater than 4.7 volts) fault code 24 is recorded in memory and the "power loss" lamp is turned "ON". At this time the M.A.P. sensor signal is used by the logic module to generate a modified throttle signal in place of the failed one.
3. Coolant Temperature Sensor. If this signal is above 4.96 volts when the engine is cold or below .51 volts with a warm engine fault code 22 is recorded in memory and the "power loss" lamp is turned "ON". At this time the logic module will use the charge temperature sensor in place of the failed coolant sensor. The radiator fan will run continuously in this mode.
4. Charge Temperature Sensor. If this signal is above 4.98 or below .06 volts fault code 23 is recorded in memory and the "power loss" lamp is turned "ON". At this time the logic module will use a default temperature in place of the failed charge sensor.
5. Wastegate Control Solenoid. If the logic module senses incorrect voltage at the wastegate solenoid, fault code 36 is recorded in memory and the "power loss lamp" is turned on. While in this mode the overboost shutoff point is decreased to 1.8 psi above the desired boost to protect the engine.

If these five sensor signals return to within specifications, while the engine is running the power loss lamp will stay "ON", and the system will stay in the "limp-in" mode until the engine is turned off. When the engine is restarted the system will operate normally. The fault code will remain in memory for evaluation by the logic module but will be cleared after 20 to 40 engine starts if the fault does not happen again.

6. Battery Voltage Sense. If this signal drops below 4 volts or between 7.5 and 8.5 volts after the engine has been running for one minute fault code 16 is recorded in memory and the "power loss" lamp is turned "ON". At this time the logic module will operated the charging system at a fixed rate.
7. Battery Voltage Too High. If the logic module senses the battery sense voltage is more than 1 volt above the desired control voltage, fault code 46 is recorded in memory and the "power loss" lamp is turned "ON".


If these two sensor signals return to within specifications, while the engine is running the power loss lamp will turn "OFF", and each system will return to normal operation. The fault code will remain in memory for evaluation by the logic module but will be cleared after 20 to 40 engine starts if the fault does not happen again.