Intermittant problem with dashboard / MIU

[carrera]

My Dame Edna has started playing up on the dashboard. I'm not using it that much these days, but I would describe the symptoms as follows:

Handbrake ( and other) warning lights come on
Tacho drops to zero
Speedo drops to zero
Engine continues to run fine

On one occasion it happened when I was cornering enthusiastically, which indicates a likely bad connection

A quick look at the wiring diagrams indicates that common points are crimp P60 on the battery positive side, and earth G41S, plus of course the single connector onto the MIU

I'm not about to start pulling the car apart in this weather, just wondering if anyone else had any experience or knowledge of this problem. I suspect it might be tricky, with it being very intermittent at present

[sgould]

I’m keeping an eye on this.  In the last week, I’ve had some niggling intermittent warnings. Already mentioned, the P1334 and the airbag light.  But now I’m having issues with the central locking. 

The auto lock on drive off mostly doesn’t work, but when it does, removing the key doesn’t open the driver’s door.  The remote is working properly (at the moment).

[carrera]

I think you have different problems

The P1334 is engine ECU, almost certainly DI just falling out of range
Airbag is independent, except for the i-bus messaging the MIU
I never use auto-locking. I'm more concerned about getting out of the car quickly than the risk of being robbed. But I'm not in a big city. Did use it in a particularly bad area of Baltimore once, but by the same risk calculation I also ensured I never came to a stop on a red light.... The drivers solenoid & switch share a common earth,according to WIS. Interestingly, connector H16-6 is common for airbag & remote unlocking

Perhaps best to allow the problems deteriorate until they can be properly tested

[sgould]

I think that will be the default.  It’s too cold to do anything at the moment!

[carrera]

Well, we had a deterioration today

Other half called me, no start situation, so I attended with Tech 2

Ignition on, no dash lights or warning lights, so I went through the process of connecting Tech 2, which then complained that there was no CANDI 

Got the unit out & was going through the process of powering it up when I moved my leg from the left of the steering wheel to the right. Her legs are shorter than mine, so they touched the dash below the steering wheel and the dash illuminated. I tried to start the car, which caught first time & drove home. There were a couple of dash incidents which didn't affect the running.

When I got home I downloaded & cleared the DTC's. there were the old favourites, P1312, P1334, P0340, plus one extra, P1460, which is an immobilisor failure.

Reading WIS it seems that the IMMO code goes from the receiver to TWICE and then via I-Bus to the MIU, which then talks to the engine ECU over P-bus. Have I got that right ?

So this is looking like a break in either the B+ or earth wires as they go up to the MIU

I assume that the check on the key / IMMO code only happens in the start position, so once running everything continues as normal

Any additional thoughts or experience ?

[carrera]

I have been studying the wiring diagrams, which has involved getting the highlighter pens out. 

The finger of blame was pointing at the feed from fuse 27 of the dashboard fusebox

So then I went into the power supply area of the MIU technical description

I think we have a winner

I suspect this require the removal of the dashboard, I had best make sure I can find the radio removal tools first

[sgould]

The symptoms do seem to point to a broken wire or a corroded connector.

Which of your may 9-5s is it?  A Damehas different wiring with the SID clipped to the back of the MIU.  No idea if this would make a difference…

[carrera]

It's the Dame Edna, I only looked at the 2006 wiring, from what I have seen the SID is downstream from all these connections, so the 1998-2005 cars should be wired in a similar way, but who knows with Saab

[carrera]

Well, fully dismantled & took the MIU out

Biggest challenge was that I didn't have the satnav removal tools so had to try & make some. In the end I removed the units from the bottom cubby hole & worked up & then the fingers were inserted allowing me to remove the satnav by pushing from the back.

There's no wires for the MIU that run under the steering wheel, so I don't understand quite how me knocking the dash with my knee brought it to life.

The blue connector on the back of the MIU was tested. Pin 17 for terminal 30, permanent live and pin 1 for terminal 15, switched live. I wiggled the wires but there was no break evident.

I took the back of the MIU off to look at the circuit board was in mint condition, so I reassembled & treated the pins to some contact spray.

Put her all back together & drove home with no sign of any problems.

"See how she goes Sir"