Hi guys,
I just bought a 1992 SC400 w/ 211k miles and I haven't been able to get the car started yet. I have reset the ECU and tried starting the car, and immediately check the diagnositc codes, and got a # 12 - no rpm signal.

What could commonly cause this? I have been reading that it may be a crank position sensor, but have also heard of faulty distributers. Can anyone with some knowledge on this shed some light on code 12, and what things to check/look for?

Thanks,
Val

 

The ECU is looking for a pulse signal from the crank sensor.
If it doesn't see one, it doesn't know what position your engine is in and is therefore unable to do anything.
There are 2 tests that can be done on the crank angle sensor.
One is a resistance test, and the other can only be done with a oscilloscope.
Take it to a competent shop if you know of one.

~Alan

 

Good news/bad news

good news: I figured out what the problem was (why the car woudln't start) and what was causing code 12 - no rpm signal. This code is thrown when there is no signal from the camshaft or crankshaft sensors for more than 2 seconds after you crank.

bad news: the reason it wasn't getting signal was because the timing belt was broken, and the cams weren't spinning. Looks like I'll be buying some parts and spending some time with the car this weekend.

Thanks to everyone that helped so far!

-Val

 

Try this if you are going to replace your V8 Belt, it was written for the LS400 but is basically the same as it uses the 1UZFE engine.

SoarerTT/V8 Cam Belt

If it runs after timing it up, replace the plugs/leads/rotors/caps while you have it stripped, if it rattles a little just when you start it up then the valve clearances will need doing as well.