Error code 45 - need help with finding cause please

[Cret]

Hi everyone

I've recently been getting error 45 on my 1989 JDM RS Legacy which is meant to be either a faulty MAP sensor or pressure exchange solenoid.

I've tried a different solenoid which I KNOW is fine and it's not that as the error was still there and my one didn't cause an error on my mate's car.

I've swapped the map sensor for another one I have and the error is still there too.

Also have checked for air leaks and and have cleaned out the TPS, maf sensor, boost solenoid, IACV etc all without any luck.

Anyone got any clues as to what could be causing this error? I badly want to get it sorted as the car is way down on power & the idle is hunting up & down quite a lot too.

Oh, and it's not the ecu either as I've tried 3 different ones which all give the same error.

Thanks!
Jim

[vrg3]

It could be a problem with the wiring somewhere.

Try the instructions starting on page 223 of the 92 Engine/Electrical FSM that Josh links to in this thread:

http://bbs.legacycentral.org/viewtopic.php?t=14485

That manual is for a 1992 US-spec Legacy Turbo but this portion should apply to your car.

[Cret]

Cheers mate, I'll have a good look through it and see if I can find anything likely.....

[vrg3]

Good luck!

(and welcome to Legacy Central)

[legacy92ej22t]

Are you getting an active CEL/code while driving, or when doind a D-check. Or are you just pulling the codes off the ecu in R-mode?

Have you ever actually cleared the code from the ECU's memory?

[Cret]

Yes the code is permanently displayed with or without test/read connectors on. I've got both mine on dash switches for easy checking!!

I've cleared the error several times from the ECU memory but the moment the engine starts up the error comes back. Don't even need to rev the engine or anything, it literally just returns the instant it fires up.

[Cret]

Right ok, I’ve been doing some testing this evening to try and get to the root of this. I swapped out a couple of parts beforehand which included removing the VTA BOV and replacing it with the original one, and replacing the vacuum hose from the manifold to the pressure exchange solenoid and from that to the map sensor.

Swapping these bits made no difference.

So next I attached wires to various sensor wires at the ecu plugs so I could easily monitor the voltages or various sensors.
After doing this I tested the MAP sensor and the pressure exchange solenoid to see what the voltage readings were compared with the specs shown on the ECU diagrams I have (for an early WRX).
The Map sensor tested:
Ignition – 2.71v
Idle – 1.47v
(Ignition spec: 2.4-2.7v)
(Idle spec: 1.4 –1.6v)

Pressure exchange solenoid tested:
Ignition – 11.66v
Idle – 13.58v
(Ignition spec: 10-13v)
(Idle spec: 13-14v)

Now seeing as the voltages being returned at the ECU are within the correct ranges for both the map sensor and the pressure exchange solenoid, I’m now really at a loss to understand why the ECU is giving error 45 which indicates a fault with one of these two. Doesn’t make sense to me.

All suggestions as to why it’s erroring when the sensors seem ok will be gratefully received as this is starting to really make me mad.

Thanks!!

[Gonzoturbo]

I assume you checked for continuity from the plug on the pressure sensor back to the ECU. Our wiring runs to close to the turbo.

[vrg3]

When you're in D-check mode, can you feel/hear the solenoid clicking open and shut?

[Cret]

Haven't checked for continuity no but if it's giving the correct reading at the ecu then it should be ok.

I've tried D check and I don't think it was operating that solenoid but I know it opens & closes because if you hold it when you switch the ignition on/off you can feel/hear it moving.

Solenoid I think is fine because I tried it on my mates car no problem and his one on my car still gave the error so I think the problem is neither of these actual sensors but something else that is fooling the ecu into thinking they are the problem.....

[GTEASER]

I hate the way a lot of these threads start and the just end, with no resolve or follow up at all.

[RoughDiamond]

He could have given up, but I suspect it could be a dead circuit in the ECU or a harness issue (he didn't mention testing the voltages at the ECU or a conductivity test on the harness).

[wtdash]

I hate the way a lot of these threads start and the just end, with no resolve or follow up at all.

HI,
...you have Code 45? What's new in your car? Rob Tune?

In the OP he tried 3 other ECUs, I'm 'guessing' it was something else and 45 was an 'extra' code....KS maybe?

Td