I have had a TST box on my truck for a couple of weeks now and no trouble. Last night the engine light came on and I checked the codes they are:

P0336 Crank Position Sensor
P0480 Cooling Fan Control Circuit
P0646 A/C Clutch Relay

I was accelerating to get on the freeway when they came up. EGT was just under 1200 and boost was 35. I have the box set at 5/5. The truck ran fine the whole time. The only other issue I have is that if I hold WOT too long I run out of fuel. I think I will buy a FASS system to fix that.

Could the codes have been caused by the TST box or is it something else?

The engine light is out now but the codes are still stored in the computer. Can I buy something to clear them so I will know if they happen again?

 

well, inactive codes ( stored) shouldnt show up on the light after so many power ups. I know on my 99 the crank position light went out after 3 power ups. you can go to most autoparts stores and they loan ( free of charge most do) a scanner so yo ucan clear the codes, , Or you can go to sears and what not and buy a scanner for 100 bucks or so that will clear them.

I think ive heard about the TST box throwin codes. but i dont have any exp and dont hang around here much hope someone with more exp in this can help ya out