[Mk2] [Turbo] Power steering

Anything to do with the electrics of the car.

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poj20
Posts: 108
Joined: Sat May 28, 2005 3:44 pm
Location: Nottingham

[Mk2] [Turbo] Power steering

Post by poj20 »

  • hi all , does anyone have or know where to locate a wiring diagram for power steering to a mk2 mr2 . K reg thanks in anticipation mick
pbmr2
Posts: 929
Joined: Fri Jun 18, 2010 12:49 pm

Re: [Mk2] [Turbo] Power steering

Post by pbmr2 »

yeah, in the BGB.

what's your problem?
poj20
Posts: 108
Joined: Sat May 28, 2005 3:44 pm
Location: Nottingham

Power steering

Post by poj20 »

Pauln
Posts: 850
Joined: Mon May 08, 2006 10:15 pm
Location: Cardiff, South Wales

Re: [Mk2] [Turbo] Power steering

Post by Pauln »

BGB = Big Green Book = workshop manual

I've never seen the original manual but assume it must have had a green cover :)

There are various online versions around, just google mr2 bgb.
eg. 1991 Mr2 Turbo BGB

When you say the power steering doesn't work, I assume the p/s warning light is coming on and the steering is very heavy. Often that's just due to a sticky relay, which you can usually clear by turning the ignition on and off about a dozen times. If you haven't tried that yet, might be worth it before getting stuck in to major fault finding.

Paul
poj20
Posts: 108
Joined: Sat May 28, 2005 3:44 pm
Location: Nottingham

Power steering

Post by poj20 »

Hi Paul , yes you’re right about light and heavy steering , I’ll try and see what happens . Cheers
pbmr2
Posts: 929
Joined: Fri Jun 18, 2010 12:49 pm

Re: [Mk2] [Turbo] Power steering

Post by pbmr2 »

yeah relay, big round one on the left hand side of the frunk. on the suspension tower.

http://carpron.com/multisite/d/387310-1 ... 479a3bdf62
shinny
Posts: 2345
Joined: Mon Nov 27, 2006 4:59 pm
Location: Reading, UK

Re: [Mk2] [Turbo] Power steering

Post by shinny »

Wiring diagram: http://shinny.co.uk/toyota/MR2_SW_1993_ ... S/ehps.pdf

(Likely not a perfect match to your car, but a very good start)
poj20
Posts: 108
Joined: Sat May 28, 2005 3:44 pm
Location: Nottingham

Power steering

Post by poj20 »

Thanks guys
poj20
Posts: 108
Joined: Sat May 28, 2005 3:44 pm
Location: Nottingham

Power steering

Post by poj20 »

Well after garage having car for six weeks , still no joy in fixing electrical problem . I supplied wiring diagram for the car but they it’s no good , not the relay , they say the problem is in the ecu . Anyone had similar problems and a solution or point me in right direction ? Thanks in advance .
Marty J
Posts: 349
Joined: Thu Oct 26, 2006 5:49 pm

Re: [Mk2] [Turbo] Power steering

Post by Marty J »

There is a fuse in the frunk which is marked ABS (even if your MR2 does not have ABS), it's also for the power steering. You might want to check that too.
poj20
Posts: 108
Joined: Sat May 28, 2005 3:44 pm
Location: Nottingham

Power steering

Post by poj20 »

Cheers , I’ll tell him .
poj20
Posts: 108
Joined: Sat May 28, 2005 3:44 pm
Location: Nottingham

Re: [Mk2] [Turbo] Power steering

Post by poj20 »

Hi, any experts on power steering ? Problem seems to be in the ecu . Anyone had similar problems and how did you rectify it ? Thanks in advance mick
Pauln
Posts: 850
Joined: Mon May 08, 2006 10:15 pm
Location: Cardiff, South Wales

Re: [Mk2] [Turbo] Power steering

Post by Pauln »

As I understand it, the ECU uses the speed sensor signal to turn the power steering off at high speed to avoid your steering becoming too "light".

So in theory I guess it's possible that an ECU fault could keep the power steering off, though I don't recall every seeing any mention of that happening.

When folks use a simple inline electronic speed converter on JDM models around the back of the speedo, this usually fools the speedo into thinking your going slower than you really are ie 70 kph rather than 70mph. Unfortunately this can also fool the power steering into thinking the same, so it doesn't turn off at high speed.

If however a Stef clamp converter/delimiter is bolted directly onto the back of the speedo gauge, this works differently and only modifies the signal going to the speedo, leaving the signal going to the power steering unchanged.

It's a really long shot, but if you have a Stef type converter it's possible that a fault in the line that passes the speed sensor signal to the power steering could be a possibility. But that really does feel like clutching at straws.

Given your mechanic seems to think this is where the problem is, if you can borrow another ECU, it's very easy to swap them over to prove whether that really is the problem.

Have you actually taken the cover off the ECU to see if there are any obvious signs of component failure?

Paul
poj20
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Joined: Sat May 28, 2005 3:44 pm
Location: Nottingham

Poet steering

Post by poj20 »

Hi Paul , I havnt done anything as I havnt a clue but he and an auto electrician are baffled , he said he looking for an ecu with same numbers ?? are you saying any ecu would be ok as long as it’s off same year and model ? He’s had it six weeks already . Cheers
Pauln
Posts: 850
Joined: Mon May 08, 2006 10:15 pm
Location: Cardiff, South Wales

Re: [Mk2] [Turbo] Power steering

Post by Pauln »

No the ECUs are model specific so it's best to stick with the correct number, as there are variants within models like with cruise control, etc.

As your turbo is K reg, I'm assuming this is a rev2. Rev 1 and 2 ECUs have a red block around the number on the label, whereas rev3+ usually have a black block.

A couple of the capacitors in the rev2 ECU are very prone to leaking/blowing with age. This usually results in more serious running issues rather than just losing the power steering. But if they leak this can easily cause damage to the tracks on the circuit board inside the ECU, but this is very easy to spot if the take the cover off.

Unfortunately finding a good s/h rev 2 ECU can be quite hard as there don't seem to be so many of them around as the rev 3. As I found out when I had to replace mine a couple of years back after the car had been left standing in the body shop for over 6 months.

Breakers like MR2 Ben may be able to help, but it won't be cheap which is why it's best to see if you can borrow one for a swap first to make sure this is the issue.

You could try putting out a plea on here to see if anyone in your area can help.

Paul
poj20
Posts: 108
Joined: Sat May 28, 2005 3:44 pm
Location: Nottingham

Power steering

Post by poj20 »

Ok thanks for your help and time ,I’ll put this to him and see where we are cheers mick
markstevieandmads
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Re: [Mk2] [Turbo] Power steering

Post by markstevieandmads »

I think pauln could be getting confused between the main ecu and there is a seperate power steering ecu too which is more likely to be the problem. Also these are more easily available.
poj20
Posts: 108
Joined: Sat May 28, 2005 3:44 pm
Location: Nottingham

Power steering

Post by poj20 »

Oh ok , where will that be located ? Cheers
Pauln
Posts: 850
Joined: Mon May 08, 2006 10:15 pm
Location: Cardiff, South Wales

Re: [Mk2] [Turbo] Power steering

Post by Pauln »

markstevieandmads wrote:I think pauln could be getting confused between the main ecu and there is a seperate power steering ecu too which is more likely to be the problem. Also these are more easily available.


Yes, sorry for confusion, I thought the speed sensor signal went via the main ECU, but looking at the wiring diagram again it actually splits at a junction point and then goes to both the main ECU and the power steering ECU.

The power steering ECU can be found in the frunk. There are a few on ebay at the moment, just make sure the part number matches that on your existing unit.

Paul
poj20
Posts: 108
Joined: Sat May 28, 2005 3:44 pm
Location: Nottingham

Power steering

Post by poj20 »

Hi , I’m glad there are people like you on here to help . Havnt a clue with cars . Thanks again mick
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