4Lo blinking?

When the light blinks it means the 4wd is not working. Nine time out of ten it is the transfer case actuator which had big problems is that car. I have included two diagrams. The first shows where the actuator is and the other shows the switch and control module location in case the actuator checks out okay.

I would also check the fuse 4WD and MET because these are the two that run the system if one is out then the system will blink.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Here is the wiring diagram for the 4wd system and a guide on how to check it

https://www.2carpros.com/articles/how-to-check-wiring

If it all checks out the 4 wheel drive module is out, try to get a used one to save money. The dealer or a repair shop may need to program it in for you.

Please let us know happens so it will help others.

Best, Ken

This means the transfer case is in 4 wheel drive low. If the car is driving normal and this light is on it means the position switch has come part internally and needs to be replaced, Here is a diagram that shows the switches location. (below)

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

If the switch tests okay I would check the actuator motor circuits and connections.

Here is another guide that can help

https://www.2carpros.com/articles/how-to-use-a-voltmeter

Please let us know what happens.

Cheers, Ken

Hi Christian2,

You should start with a diagnostic scan to retrieve the trouble codes. Let us know the EXACT Diagnostic Trouble Code and we will try to help you figure this out.

The diagnostic scan indicates 3 items related to the Check Engine and 4WD blinking.

P2240 and P2241 are faults with the O2 sensors and these results in the Check Engine Light coming on. These are usually due to faulty sensors and rectified by replacing them.

C1268 is a fault with the 4WD switch or its wiring. You would need to check for wiring or switch fault.

When you remove the battery the codes are erased from memory. Then when you reconnect it and run the engine they will return because the problems have not been repaired. Completely normal.
The codes all indicate circuit faults, KHLOW2008 is correct in having you check the wiring from the sensors and transfer case harnesses, these codes could all be caused by a short or broken wire in the circuit. Especially as they are intermittent. Look at the harness and any sharp corners or brackets including hitting the exhaust.

That would be the power steering pressure sensor.
Toyota part # 8944834020
Wells # PS686
Good work finding the melted wiring.

That code would not cause the 4Lo light to blink. You have two different problems. For the blinking 4 lo a factory level scan tool can pull the codes that are stored in the TCM/TCCM and give you a better idea of what to check.

Dealer or a good shop. Not the free scan places, as the tools that most of them use will not read the codes in that module.

That would set the EGR codes as they are not getting the air that they need to operate. It is behind the splash shield on the drivers side on the US version. I would check all the hoses it uses to feed air to the system as well to be sure it is not just a plugged or broken line.
The replacement is not hard. Remove the fender liner and remove and replace the pump. Check that the connector is clean and apply a bit of dielectric grease to it to keep it dry.

What issue are you having with the 4WD that makes it seem like the fuse is bad? There isn't a separate fuse for 4LO, The system is powered by the single fuse labelled 4WD Fuse. If the other modes work but not 4LO you have a different issue. What vehicle are you working on?