Author Topic: U12 TRX - FailSafe Mode (2400 rpm limit) (Read 8718 times)

trxtom · « **on:** May 29, 2007, 04:23PM »

Hey guys, I'm new here, driving a Bluebird Trx Superhatch as the NZ exports were called (same as pintara i think) and have been having serious issues with the ECU going into fail-safe mode, limiting the revs to 2400.

Just paid a mechanic over $700 (NZ) for (apparently) around 10hours work yet with NO RESULTS! He tried replcing the ecu and the airflow meter which did nothing then upon replacing the distributor the problem was solved. Then after a week over having it back from the shop it dropped back into fail-safe mode.

The only code the ECU spits out is 41 which I think is the "air intake temperature sensor", my trusty mechanic 'friend' assured me this is not the issue and also that me replacing the standard panel filter with a pod 6 months ago has nothing to do with it.

Really wanna get this car going again as it's an awesome ride...
Any ideas much appreciated...

Budgie · « **Reply #1 on:** May 29, 2007, 04:49PM »

Air intake temp sensor sits on the side of the airbox. Designed to detect high intake temps, then ECU retards timing to avoid pinging.

Its a seperate device to the airflow meter.

When you had a pod connected, what did you do with this sensor?

chr1S · « **Reply #2 on:** May 29, 2007, 04:54PM »

The AIT won't be doing this, mines been removed for a year now.

Can you do me a favour and check your grounds around the engine bay, look around the distributor (there is a ground there), look on the intake manifold (there is two there) - make sure they are done up tight and in place correctly.

go around the TPS, CAS, and other electrical sensors and shake their wires around vigorously to try and get them to contact correctly again.

I had my car go randomly into limp mode once and then hop out of it, turns out after checking the engine bay my ground next to the distributor was loose.

trxtom · « **Reply #3 on:** May 29, 2007, 05:08PM »

Air intake temp sensor has just been dangling since I put the pod on, most people I've asked said it should be fine there. Pretty sure the mechanic checked the grounds as he said he had to tighten a couple but I'll have a good look in the morning.

The problem actually started about a year and a half ago for the first time, at which point another sensor was stuffed and not switching on the radiator fans, when I took it to the local Nissan dealer to sort that out they replaced the faulty sensor which in turn fixed the fail safe problem for a good year or so.

The time it takes for the ECU to drop into fail-safe varies a lot, sometimes after 30seconds of driving, sometimes half an hour. Also I should mention the speedo turns on and off randomly but doesn't seem to time in with the ecu limiting.

xxxx · « **Reply #4 on:** May 29, 2007, 05:22PM »

deffinately the little speed sensor on youre gearbox is faulty... as soon as that malfunctions the car will go into limp home mode... should be a cheap fix at no more then $50

rathies · « **Reply #5 on:** May 29, 2007, 06:01PM »

yup speed sensor will cause these symptoms. that is limp mode and your speedo dropping out. your u12 will also do this if you try to drive it without a dash cluster, so that can even point to a faulty cluster.

Jono · « **Reply #6 on:** May 29, 2007, 06:57PM »

The copper tracks on the back of the cluster can fatigue and break, check them for cracks.

trxtom · « **Reply #7 on:** May 29, 2007, 09:34PM »

Haha I guess the fact that i usually have to give the plastic face of the dash a quick solid hit to get the fuel and temp gauge working points directly at a faulty dash cluster then?

I'm an electronics student at Otago Uni in NZ with quite limited knowledge of engines, do you recommend attempting to fix/replace the dash cluster and speed sensor myself or is this the work of someone more qualified?

Colby · « **Reply #8 on:** May 29, 2007, 10:03PM »

yeah do it yourself... speed sensor is as simple as one bolt on the rear top of the gearbox and unplugging it.

The dash is ennoying, but if you look over the DIY LED cluster article on here it tells you how to pull your cluster out... could be fun to do the LED's while your at it

rathies · « **Reply #9 on:** May 29, 2007, 10:13PM »

its most unlikely that its your speed sensor at fault. when we did trx_reeces engine swap the wire broke off the speed sensor, the car didn't have any rev limit whatsoever. so i'm gonna put my money on the dash cluster.

Today the fuse for my dash cluster blew twice (thank god i'm getting it off the road next week) right after i posted in this thread. all the needles in the cluster didn't work but i can assure you there was no 2,500 rpm rev limit. so i'm gonna put my money on the actual cluster being broken, unless someone can think of other things to consider?

trxtom · « **Reply #10 on:** May 30, 2007, 12:27PM »

Hey, pulled the dash completely to bits (those things aren't made for european hands) , I take it the cracked wiring you suggested would be somewhere on circuit below? cause it looks pretty sweet...

Nothing stands out as obviously broken, any way I could check/test each gauge?

Jono · « **Reply #11 on:** May 30, 2007, 07:45PM »

Hold it up to the light and see if you can spot any cracks in the tracks on the plastic film. If you can't see any then it's probably your speed sender on the gearbox.

Colby · « **Reply #12 on:** May 31, 2007, 02:36PM »

or make a little circuit tester and test the links between the offending guages and their plug sockets.

rathies · « **Reply #13 on:** May 31, 2007, 04:53PM »

yesterday my dash fuse in my red trx blew again (wiring problem), drove good for about 3 minutes, then it started limping, I still think the speed sensor has nothing to do with it jono.

ffourc · « **Reply #14 on:** May 31, 2007, 06:04PM »

Lots of dash talk, but have you ruled out it's not a harness or connector issue, I'd personally have double checked the AFM CAS ECU - in your case.

buying a spare ecm is a good idea if you can find one cheap - just to rule it out (here they're $45 if u can find one at the self serv wreckers)

chr1S · « **Reply #15 on:** Jun 9, 2007, 08:25PM »

sigh..

i just jinxed myself, that limp mode problem came back LOL...

i'll piss around with it tomorrow.

rathies · « **Reply #16 on:** Jun 9, 2007, 09:15PM »

what does the ecu tell you when you ask it whats up??

chr1S · « **Reply #17 on:** Jun 10, 2007, 02:21AM »

code 21 if i remember, AIT.

always been there, never given me a problem. i shall sus tomorrow during the day.

trxtom · « **Reply #18 on:** Jun 10, 2007, 01:24PM »

Think i've got mine sorted thanks guys, pulled out the speed sensor and had to pull it to bits and do a bit of soldering, chucked it back in and the car went sweet for decent length drive, also speedo worked properly. Pretty average fix though as it just died again. Really need to replace it but haven a bit ov trouble getting one here in NZ. Called up nissan and apparently they cant get em anymore.

rathies · « **Reply #19 on:** Jun 10, 2007, 01:33PM »

afaik they're the same on all u12's. surely there is one wrecking somewhere??

chr1S · « **Reply #20 on:** Jun 10, 2007, 02:06PM »

well i fixed mine first go,

i had a weird idle so i checked out the maf, it wasn't even getting power heh..

fixed that, all good, going for a spin soon

.

rathies · « **Reply #21 on:** Jun 10, 2007, 02:40PM »

yea like january.

lol!! sorry mate had to have dig

chr1S · « **Reply #22 on:** Jun 10, 2007, 02:47PM »

lolol,

car goes like nuts

Budgie · « **Reply #23 on:** Jun 10, 2007, 06:18PM »

Quote from: rathies on Jun 10, 2007, 01:33PM

afaik they're the same on all u12's. surely there is one wrecking somewhere??

The aussie built U12's had differant sensors (cable and electronic) to the jap built cars, which are everywhere in NZ.

trxtom · « **Reply #24 on:** Jun 11, 2007, 09:57PM »

yea i was hoping that wasnt the case. Any chance anyone has a spare one or knows of one (vehicle speed sensor for ka24e u12 trx) at a wreckers close to you? Postage to NZ of that size can't be too much can it??

would be very grateful...

rathies · « **Reply #25 on:** Jun 11, 2007, 10:09PM »

yer i can sell you one off an auto KA, i can confirm the manual and auto item are the same. only problem is i'm on oz and your in nz ya? how much would you want to pay??

trxtom · « **Reply #26 on:** Jun 12, 2007, 07:41AM »

ive got no idea wat it's worth but would $50(AUS) cover it? Plus postage should be between $10-$15 somewer i think

rathies · « **Reply #27 on:** Jun 12, 2007, 09:16PM »

yeh sounds good. how do you want to pay? paypal seems to be the easiest option as i've tried to transfer money from aus account to nz before and had it decline.

Colby · « **Reply #28 on:** Jun 12, 2007, 11:50PM »

U13 sensors are the same as U12 items for the KA box.

Ammerty · « **Reply #29 on:** Jun 12, 2007, 11:59PM »

that they are