2JZGTE ecu error code 12

[2JZR31]

I keep getting error code 12. And I can't get rid of it. The check engine light only comes up if I hold the engine at above 3000rpm for a little while. So it comes on when I rev out 3rd gear = not good for quarter mile times or MPH. It doesn't do it every time and the check engine light goes off when I turn the ignition off then back on. I changed both cam sensors with secondhand ones of unknown condition. Is there a way I can test the sensors somehow? What is the "NE" or "G1" and "G2 signal" The engine remains smooth when the light comes on. There is no hesitation or anything when it happens. Could my CAS be stuffed? I would have thought it would hesitate or something if it was getting a CAS error?

http://www.mkiv.com/techarticles/eng...bd1_codes.html

[CrUZida]

You have a crank angle sensor near the crank pulley.
And 2 cam angle sensors on the intake cam. One near #2 and one near #5 from memory.

If its only happening at higher revs, I'd hazard a guess that you are getting interference from somewhere?

[wilbo666]

Cam angle sensors aren't used after the engine is started and running...so if one of them was failing it shouldn't effect how the engine runs...(to my knowledge)

That isn't to say that the ECU doesn't check them while the engine is running, and throws codes etc if they aren't working...

Are you clearing the code after it gets thrown?....

I'd start with a continuity test to the sensors -> ECU...

....

Cheers
Wilbo

[2JZR31]

You have a crank angle sensor near the crank pulley.
And 2 cam angle sensors on the intake cam. One near #2 and one near #5 from memory.

If its only happening at higher revs, I'd hazard a guess that you are getting interference from somewhere?

I replaced the 2 cam angle sensors (bit off a prick to do) but they were secondhand and of unknown condition. So I want to be able to rule them out somehow if this is possible. I have heard they stuff up quite a bit so its possible I put a stuffed one back in. I have not changed the CAS yet. Its also a prick to get to and then I would need to find a CAS to use.

Not sure about interference ? That sounds like a real prick to find.

[2JZR31]

Cam angle sensors aren't used after the engine is started and running...so if one of them was failing it shouldn't effect how the engine runs...(to my knowledge)

That isn't to say that the ECU doesn't check them while the engine is running, and throws codes etc if they aren't working...

Are you clearing the code after it gets thrown?....

I'd start with a continuity test to the sensors -> ECU...

....

Cheers
Wilbo

Once the check engine light has come on I can clear the light be reseting the ignition with the key, but the code 12 stays in the ECU. The engine always starts fine and it only happens at high RPM. It used to do it all the time but it somehow got better.

I might do the continuity test to rule that out.

[CrUZida]

I would have thought if any of the sensors were faulty (ie, out of spec, wire back to ecu), then they would throw codes at all times.

Its the high RPM only that suggets to me interference.

I'd start with making sure each ones grounds are all in intact.

[wilbo666]

It might be interference, it might also be a connection that is intermittent due to the vibration?

Cheers
Wilbo

[Alchemist]

Not going to help exactly in this situation, but in my experience with faulty O2 sensors from my 2JZ-GE the ECU did not list the sensors as faulty even though the values they were sending the ECU out of range(thus my car running crap). Only discovered it by driving around with a mechanic and a ECU hand scanner and watching the values it threw out. Disconnecting the sensors did light up the ECU check light though.

Might be an idea to download the service manual off supraforums.com.au get the values for some of the sensors and try to get access to a odbII hand scanner, or take it to a mechanic and get them to check out the sensor values.

[2JZR31]

How would I test for interference?

[Draven]

make sure you haven't wired your sound system power cable next to your CAS line?

Also check the integrity of the CAS cable (this will become difficult/impossible where it goes next to the fuel rail)

[2JZR31]

Does it with stereo off and with the alternator not charging... Prick of a thing...

Alchemist. Do you know where I can find those values for the sensors?

[Alchemist]

I'm guessing you are the same user from the supraforums Just goto supraforums.com.au under the MKIV section there is a zip file of all the Service Manuals for the 96+ Supras. It's under the section Troubleshooting Without Error Codes I think...theres a stack of info there that may help you out too.

[Mr Ed]

Here ya go. From the old Toymods forums. (link below). Had this same problem on my car. Ive posted this on SF for ya but thought Id chuck it up here for the Toymods guys while Im at it.

CRANKSHAFT POSITION SENSOR INSPECTION
NOTICE: Cold and Hot in the following sentences express the temperature of the sensors themselves.
Cold is from -10°C (14°F) to 50°C (122°F) and Hot is from 50°C (122°F) to 100°C (212°F).

3. INSPECT CRANKSHAFT POSITION SENSOR RESISTANCE
Using an ohmmeter, measure the resistance between terminals.
Resistance:
Cold
NIPPONDENSO
835 - 1,400 Ohms
AISAN
985 - 1,600 Ohms
Hot
NIPPONDENSO
1,060 - 1,645 Ohms
AISAN
1,265 - 1,890 Ohms
If the resistance is not as specified, replace the crankshaft position sensor.

http://forums.toymods.org.au/index.p...art=0&count=60

[2JZR31]

Cheers guys. I will try and take a look at it tomorrow.

[2JZR31]

I tested it all with a multimeter and an CRO. All seems fine.

I think it might be the trigger disc for the CAS. I have heard they can come loose and I am pretty sure mine has.