How Limp to Safety works
If the engine begins to overheat:
²The engine coolant temperature
gauge will move to the red (hot)
area.
²The
symbol will illuminate.
²The ªService Engine Soonº
indicator light will illuminate.
If the engine reaches a preset over-temperature condition, the engine
will automatically switch to alternating cylinder operation. Each disabled
cylinder acts as an air pump and cools the engine.
When this occurs the vehicle will still operate. However:
²The engine power will be limited.
²The air conditioning system will be disabled.
This system has given you an early warning of engine damage and you
should immediately drive to a place of safety where the engine can be
cooled or the vehicle towed to a service shop. Continuing to drive in this
Limp to Safety mode will increase engine temperature some more,
increasing the chance of engine damage, and:
²The engine will completely shut down.
²Steering and braking effort will increase.
If you have decided not to have the vehicle towed, and when the engine
temperature cools, you try to re-start it and it appears to have returned
to normal operation, don't delay in getting to a service facility as soon as
possible to diagnose what caused the overheat and prevent further
engine damage.
When Limp to Safety mode is activated
You have limited engine power when in the Limp to Safety mode, so
drive the vehicle with caution. The vehicle will not be able to maintain
high speed operation and the engine will run rough. Remember that the
engine is capable of completely shutting down automatically to prevent
engine damage, therefore:
1. Pull off the road as soon as safely possible and turn off the engine.
2. Arrange for the vehicle to be taken to a service facility.
3. If this is not possible, wait for the engine to cool down.
Maintenance and Specifications
207
Readiness for Inspection/Maintenance (I/M) testing
In some localities, it may be a legal requirement to pass an I/M test of
the on-board diagnostics system. If your ªCheck Engine/Service Engine
Soonº light is on, refer to the description in theWarning lights and
chimessection of theInstrument clusterchapter. Your vehicle may not
pass the I/M test with the ªCheck Engine/Service Engine Soonº light on.
If the vehicle's powertrain system or its battery has just been serviced,
the on-board diagnostics system is reset to a ªnot ready for I/M testº
condition. To ready the on-board diagnostics system for I/M testing, a
minimum of 30 minutes of city and highway driving is necessary as
described below:
²First, at least 10 minutes of driving on an expressway or highway.
²Next, at least 20 minutes driving in stop-and-go, city-type traffic with
at least four idle periods.
Allow the vehicle to sit for at least eight hours without starting the
engine. Then, start the engine and complete the above driving cycle. The
engine must warm up to its normal operating temperature. Once started,
do not turn off the engine until the above driving cycle is complete.
Maintenance and Specifications
219
