Dieclublex

Hi, my GS 300's cooling fan runs imediately i switch ignition ON but car won't start, the engine light disappear on 2nd attempt to start,"check VSC light" this happens even after 5 days of not touching the car, wat could be wrong? Any similar experience? I've cleared all the DTCs /fault codes with Inteligent Tester Lexus machine. But still doesnt wanna start. At first it could idle but not last for a minute

Sodium

Have you checked the fuses and tried unhooking the negative battery terminal for 10 minutes? Also, when you try to start the car do you hear the engine turning over? And by "cooling fan" do you mean air conditioning fan, or radiator fan?

Dieclublex

radiator fan, the battery neg terminal i did disconect/unhook several times and even used the original lexus diagnostic machine to clear fault codes but proplem still persist, no fuse or relay blown

Sodium

Hmm well you could have a bad alternator, and a battery without sufficient charge for running spark plugs and starter motor, but enough to power the radiator fans. Could also be a problem with the engine immobilizer/security system. Or maybe the fuel pump has failed or the fuel filter is clogged.

Do you hear the starter motor cranking the engine when you try to start the car?

Also, did you save the error codes? Probably the easiest way to diagnose the problem (or at least the best starting point) would be to look them up and post them up here. Plenty of members here will be able to tell you what the codes mean and how you might go about solving them.

NotADood

Lexus Master Technician here,

There is a common problem among high mileage 2006 GS/IS models. What happens is that the high pressure fuel rail pressure sensor shorts out and brings down the entire vehicle network. This results in cooling fans running on high, and no CEL. To see if this is it, remove the upper intake manifold, and possibly the lower intake manifold. Find the passenger side high pressure fuel rail for RHD vehicles (not sure what side of the road South Africans drive on), and unplug the sensor that is at the back of the fuel rail. The engine should crank if it is unplugged, although a CEL will be illuminated.