The ignition switch provides circuit power and the ecm provides the circuit ground that illuminates the mil.
Mil operation is checked visually: it should be illuminated when the ignition is first turned on. If the mil is off all of the time or on all of the time, use the procedure below to troubleshoot it. The mil is used to indicate the ecm’s detection of a vehicle malfunction.
Follow this procedure using the hand–held tester or an obd ii scan tool to determine the cause of the problem and to check the mil.
Wiring diagram
Inspection and adjustment procedure
1 Tire valve
2 Tire pressure gauge
1 Remove the tire valve cap.
2 Press the tip of the tire pressure gauge onto the tire valve.
3 Read the pressure using the gauge gradations.
4 If the tire inflation pressure is not at the recommended level, adjust the pressure.
If you add too much air, pres ...
Problem symptoms table
The suspected circuits or parts for each problem symptom are shown in the
table below. Use this table to
troubleshoot the problem when a normal code is displayed in the diagnostic
trouble code chart but the problem
is still occurring. Numbers in the table indicate the order in which the
circ ...
On–vehicle inspection
1. Inspect cooling system for leaks
Caution:
to avoid the danger of being burned, do not remove the radiator
cap while the engine and radiator are still hot, as fluid
and steam can be blown out under pressure.
fill the radiator with coolant and attach a radiator cap tester.
  ...