ECU Code 12 and strange timing

[svpmx83]

Any hints Gentlemen?

I have ecu code 12 whic is supposed to be cam or crank sensor faults
Crank sensor tested at 1250ohms both cam sensors at 1300ohms, all sensors tested all the way back to the ECU. The manual states that if the sensors test ok (the range is 950 to 1250ohms) that the ecu should be swapped. I have a spare ecu and swapping them has made no difference

static timing is showing as 4deg btdc on crank pulley and actually retards to 0deg!!! as the revs rise. performance is poor as you would expect. But no misfires or rough running at idle or above.

Both Toyota and I have checked cam timing and this appears to be correct, I will check again tomorrow.

Does anyone have a good cam sensor that they can check the resistance of?

Could something else be causing a code 12?

 

[hi-lex]

im gettin the same on the falcon ive just done conv to, also geting 14 15 as well, maybe neet to look at wiring as it all worked in the half cut

 

[svpmx83]

14 and 15 are the ignitors if that helps you

 

[svpmx83]

Update:

I had Toyota reset the valve clearances a few days ago - and on getting the car back had the Code 12 error. This got me excited as I thought we had found the issue with engine performance. It turns out that the goose that worked on the car used silicone to seal the cam covers and managed to get a dollup of silicone on the G2 sensor wheel - I've cleaned it off today and the error codes are now gone. Bummer, as the timing is still static at 4deg advance.
Does anything else trigger limp home but not generate a code?

 

[Peewee]

Try swapping some sensors with ones you know work.

Ones I'd try are AFM, TPS, ... , that or another ecu perhaps?

Knock sensors shouldn't come into play until you reach a few thousand rpm so I doubt its that.

 

[svpmx83]

Thanks Peewee,

Code 12 is back so it looks like the cam position sensors.
The resistances when cold were about 1150ohms on the cam sensors but when checking the NE G1 G2 outputs with a frequency capable multimeter, I get G2 90hz, G1 48hz and NE 120hz. At idle at 600 rpm the crank is correct at 120 but both cam sensors should be returning about 5hz. Also the ac voltage generated by the cam sensors is about half that of the crank sensor. The wiring tests ok all the way back to the ECU and as i said I've swapped ECUs although its possible that both of them may have a fault, it's unlikely.
In full test mode (TE2 earthed) I still only get code 12 so I'll replace the cam sensors and hope for the best. ($205 each, bummer) :blindfold

 

[Peewee]

You should be able to get some 2nd hand ones.
I should have a spare one here, not sure how much wire is on it, as I know I cut it. (I only use one for Microtech).
Almost anyone on an aftermarket ecu will only be using one.

And yes, the cam sensors should be running at 1/24th the frequency of the crank sensor, so 5hz for 600rpm should be perfect.

Maybe pull the sensors out and give them a clean?
Possible you are getting interference?

 

[svpmx83]

I've pulled them and given them a clean and no change, so at least the new sensors will eliminate that as a fault. The engine is definitely in limp home mode as the timing is locked at 5deg btdc. it must be getting a reasonable signal at cranking speed but going screwy once the revs rise to idle speed. code 12 is the only error and I can't see anything that would be causing interference. The right side sensor plug is directly under the ignition coil, and I would think that that would cause interference if the design was susceptible.

 

[MacroP]

Have you checked the shielding cable around the sensor cables through the loom is properly earthed?.

 

[svpmx83]

Thanks Marco, yes the shielding tests ok to ground.


I'm just wondering now whether i've made some goof up in the wiring in the early stages of the swap that managed to fry the timing stages of both ecu's, although to date the only errors in wiring I've managed to find related to the air conditioning magnetic clutch sense, and traction control disable. I even considered going to aftermarket ecu but it all seems to point to a sensor or wiring fault.
In the last 6 months or so the engine has occasionally kicked back on starting which makes me think that I've always had one dead cam sensor and the error code has only surfaced as the second sensor began to fail? I've rewired the poor thing several times, but as with most things I may have an error I can't see as my wiring info is based on US diagrams for the GS300 for the body control plugs. I've used sc400 diagrams for the 40 pin ecu connector.
I'm seriously going to throw a party if I get this resolved.
Oh and Toyota suggested that I was lucky they allowed my "Import" to be booked in for a valve shim service. The rumours are true that Toyota Oz has a policy against imports. Idiots, my car is in their system only because I bought it off them in 1992, and it's the second and LAST time they have seen the vehicle since the warranty expired. OK, I've changed motors but every part apart from the cooling fans has been purchased from the same dealership for 14 years. Oh and they suggested that the 1uz is not the same as the one in the LS400 sold here. Who hires these people?

 

[Peewee]

What cut did the motor come from?

UCF10?
40P-40P-40P ecu?

 

[svpmx83]

What cut did the motor come from?

UCF10?
40P-40P-40P ecu?

UZS141 40P-40P-40P same as soarer with gs300 body plug as it's the same chassis as the JZS14x lexus. Shane (Cool1 on Toymods) and I wired up a MX73 here in Brisbane with the same wiring information with no problems. The cut only had a small bingle on the drivers side front so I'm wondering whether or not the owner junked the car for the same fault I'm now chasing. It had had the cam belt and ignition leads/plugs/caps changed only a few thousand k's before the vehicle was chopped up.
Crossing fingers here now, as you know I've had problems with performance for 2 years since the swap. I'd always suspected it was either traction control issues from the lack of the TC ecu signals or timing retard triggered from the tappet noise. Now I finally get an error code repeatedly as in the past it was only intermittent when checked and was explained by my alarm system disabling the starter relay, which caused the ecu to see the STA signal but no engine rotation. Limp home mode for Two Years and 30,000 km's! I love toyota engineering.

If these sensors don't fix it I'll have to find a running soarer i can test my ecus on

 

[svpmx83]

also as magetism can be diminished over time by heat it would make sense that the cam sensors would fail before the crank sensor as there is no cooling airflow behind the covers and they are bolted directly to the heads

 

[MacroP]

How about a suspect igniter or igniter wiring?. The igniters send feedback to the ECU through the terminal IGf and can force the engine into limp mode. Could you swap the igniters plugs over and see if the fault code changes to 13 instead of 12. Just a thought.

 

[svpmx83]

damn good idea marco - i'll let you know in a couple of minutes

 

[svpmx83]

Nope, ecu reset and ignitor plugs swapped over, still Code 12. Which is probably a good thing after ordering $400 of sensors :veryhappy

 

[Peewee]

Hmmm, something just triggered for me.

Have a read.
http://forums.toymods.org.au/index.php?t=msg&th=81180

I was (and AFAIK still am) having the same issues with a friends 1JZGTE.
Wiring is perfect, AFAIK, timing belt was never changed (so unless error occured in Japan).

This one the CEL doesn't turn on while driving.

Do this for me, clear the codes, bridge TE1 and E1, turn the key, and watch the CEL.
On this car, the CEL will flash normal for 3 seconds, and then go into code 12.
Which to me means STA is getting ignition volts, but I've check it, and it doesn't, unless there is an internal fault.
Haven't checked for limp mode though.


Never having had my car in limp mode, how can you test.
Timing light on, and bam, 4deg? or does it need revs? load? speed?
4 deg regardless of revs?

 

[svpmx83]

I was going to ask you if you had resolved this.
I found this and Norbies thread on the 2J last night, and unfortunately I dont have code 12 generated until the motor is started. I tried the same test after ecu reset and the CEL just flashes normal whilst ignition is on.

I also don't have the warning light on while driving - unless TE1-E1 is bridged. Limp Home is 5deg timing regardless of engine revs, so the timing actually retards as revs climb due to delays in the signals. So yes the easiest way to test would be a timing light if it shows 5deg regardless of TE1 being grounded, its in limp.

The only test that has failed for me is the frequency and ac voltage test of G1,G2 and NE. All of the factory suggested tests are within spec. The 2JZ fault that Norbie had sounds exactly the same as my problem.

 

[svpmx83]

is is possible one of your ignition power feeds is getting full time B+ and therefore the code memory is not clearing?

 

[Peewee]

Pretty sure the battery was disconnected for many a week.

Also he reckons it doesn't have the power it should, but it still makes 7psi, so I don't know.
Haven't personally driven the car yet, so can't comment.

Will attemped to get back there one day in the future and check the timing.