Modes of Operation

In this mode, the Logic Module or SMEC compensates for the failure of certain components by substituting 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 either too low (below 60 degrees F) too high (above 300 degrees F) or changes too fast to be real, fault code 22 is recorded in memory and the "power loss" lamp is turned "ON". At this time the charge temperature sensor signal is used by the logic module in place of the failed one.
4. Charge Temperature Sensor. If this signal is either too low (below 60 degrees F) too high (above 300 degrees F) or changes too fast to be real, fault code 23 is recorded in memory and the "power loss" lamp is turned "ON". At this time the coolant temperature sensor signal is used by the logic module in place of the failed one.

If these four 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 30 engine starts if the fault does not happen again.