For i4wd DTC reading and troubleshooting, refer to the i4wd troubleshooting page.
The i4wd warning light is triggered by system faults, the most common being:
There are 4 speed sensors, 3 front, and 1 rear. They all go directly into the differential. Sometimes water, condensation, or dust can get into the connectors. Unplug the connectors, clean them out with compressed air, add dielectric grease (spray with WD40 in a pinch), then connect and reconnect a couple times and leave connected. Drive around in a figure 8 pattern for a few minutes and see if the light goes off.
Tire pressure, like excessive tire wear, can cause size differences between the tires. Because i4wd is a very sensitive system in order to be highly reactive while driving, it is important to keep the tires the same size. Check and correct tire pressure then drive around to see if the light goes out.
Important note for owners with stock wheels: If you have put non-factory tires on your factory wheels, you must equalize your tire diameter by adding 2 to 4 psi additional pressure in the rear tires. This will correct for the fronts being 7 wide and the rears 10 wide.
Check the spring the brake pedal, a number of i4wd lights have occurred due to the pedal return spring breaking, becoming stretched, or mount issues.