4WD and ABS lights on... no error code on ATESSA ECU

[MrAceman]

When I bought my 89 GTR last month I knew that it was only working in 2WD. The seller told me that his mechanic told him that, "It's a faulty front right speed sensor". Back in those days I didn't know about the ATESSA ECU codes, so I didn't confirm the mystery diagnosis.

However, before taking the word of a mechanic I'd never met and simply sourcing a new speed sensor, this evening I set out to make progress on getting my R32 GT-R working in 4WD. I started by checking the ATESSA ECU code and didn't find anything wrong. Next I checked the fluid reservoir in the right side of the trunk and it was dry. I figured that was the issue. So I filled it (Royal Purple ATF) and bled the system using the standard procedure (bled both valves).

Now I've got a full reservoir, a hopefully adequately bled system, and still no ECU error code. However the 4WD and ABS lights are both still on.

Any suggestions on what to try next?

[nickisonfire]

Did you have the air bubble at the right place and the right size in the rear attesa reservoir ?? Do you bleed with the connector inside the driver kickpannel??

[steveo1502]

Both fuses? One in the dash and one in the engine bay

[MrAceman]

Air bubble in reservoir - Yes, I believe it's correct. I've got a current picture, but I can't attach it. It looks similar to many of the ATTESA reservoir pics I've found on-line.

I didn't use the connector in the driver's kick panel to run the pump. Rather, I used the relay in the trunk. Since I didn't have any ECU error lights I wanted to check that the relay was operating. It seems to be just fine. If you don't know what relay I'm referring to... https://www.youtube.com/watch?v=vgG9g85K_mA

(Although, now as I re-read the information, it seems like that the trunk relay may just trigger the ATTESA pump while the driver's kick panel connector runs an air pump that forces air pressure into the system? Can anyone shed some light on that?)

Not both fuses... both ATTESA bleed valves. The rear one directly above the rear diff, and the front one near the back of the trans.

I opened both valves and triggered the relay in the trunk. It pulled fluid through, but not nearly as much as I expected.

I'll give it another shot this evening with the "standard method" and see if I get a different result.

[MrAceman]

Standard being... http://www.skylife4ever.com/2011/01/...ng-attesa.html

[rob_96]

I had no code however the abs light and awd light on, I tired everything from swapping fuses to tracing wires

Then I bought a AWD ecu for 37 shipped to my door from Nengun, swapped the ecu and boom awd was back

[MrAceman]

I like the sound of that... Obviously that's extremely wishful thinking on my part that it'll be that "easy"... but for that price range I'm willing to take a gamble.

Also... damn you for introducing me to that site.

[rob_96]

ohh man that site is dangerous.... no problem

I wondering if there is anywhere i could send mind to get fixed

The ECUs are cheap man 37bucks doesnt hurt the bank

[rob_96]

http://forums.gtrcanada.com/parts-sale/63494-gtr-r32-parts-sale.html

I think he has one for sale

[MrAceman]

Yeah, I PMed him yesterday. No response yet, but hoping for the best. Thanks for the suggestion. Hopefully that's it.

[Skym]

Best way to tell if it's the ECU, is to earth part of the 4wd ECU plug that links to the dash (need a pinout diagram). That will turn the warning light off on the dash. It's the same way you earth the cat overheat sensor to the exhaust to turn the warning light off on the dash.

The 4wd, HICAS, Engine ECU's fail or malfunction due to bad solders (sometimes don't show error codes when they do this). Also the dash, AFM's all have the same bad solder problem. Desoldering, resoldering seems to fix most problems with those parts.

But check rear window for leaks, trunk lid for not being closed properly (adjustment bolts x 2? is in the lower back of the trunk), as sometimes water leaks onto the HICAS, 4wd / ABS ECU's. If see water marks on the top of ECU, you have the culprit. A solution is to turn the ECU upside down so the breather holes face downwards.

[MrAceman]

Well... the new ATTESA ECU makes no difference.

I'm experiencing what seems like some additional odd behavior, but I'm not sure, so I'll explain it and see what you guys think may be going on. The car has a "kill switch" for the 4WD system (tough to tell what it does when the system is already dead...).

When I flip the switch into what I'd imagine is the RWD only position I get a couple things:

ABS and 4WD dash lights go off temporarily. ABS generally stays off and the 4WD light comes back on in 5-10 seconds. I also get 3 different error codes on the ECU.

18 ETS pressure switch or circuit
19 ETS motor, motor relay or circuit
21 Throttle sensor or circuit

I've been going on the assumption that when I flip the switch and put the car into what I think is forced RWD mode, that I'm bypassing something that legitimately fires those codes. But due to my lack of experience with the system I've decided to stop assuming anything anymore.

1. Would you expect the ECU to fire those 3 error codes when a RWD kill switch is flipped?

2. If NOT, is it possible that the kill switch is backwards and, when it's in the assumed "normal" position I've had it in I'm actually in RWD and the ECU simply isn't getting any power to post error codes?

3. If it's possible that the kill switch is backwards, what's the chance that the 18, 19, and/or 21 codes are legitimate and the issue?

4. If the ECU is working as expected... are any of you experts visiting Atlanta, GA anytime soon? If so, do you need free room and board and free use of an 1989 GTR while you are in town in exchange for helping me fix this issue?

[caliber676]

It's safe to say you have a functional ecu. You mention something about a low amount of fluid flow. You have fault codes relating to the pressure switch which can signal from a bad switch or low pressure. You also have a fault for the motor which would cause low pressure thus the switch fault. I'm assuming you have checked your power, grounds and voltage drops across the attessa pump and switch circuits in accordance with the faults? If you haven't, do so. If that checks out electrically then get a appropriately rated pressure gauge and check your attessa system pressures pressure. If you've deemed your ecu is working then assume the codes it's setting are relevant to your issue, they usually are.

[r32_nate]

1.) whats your pump sound like when you bled it? strong constant humm like a pump should? or was it weak and/or intermittent? I recently did mine, having an issue where 4wd would surge under full throttle. Took me 10 months to figure out that when bleeding the system, the pump should be smooth like a fuel pump an not intermittent.

2.) check you wiring with ur 4wd controller switch, make sure its disconnecting the fuse and no the pump its self.

3.) check your g sensors under ur arm rest. Mine was bad at one point, but I got no warnings from the stupid computer blinky light lol. Its easy to calibrate, just google how.

[r32_nate]

duplicated my post ^ in error