Code 42 Advice

Firstly, I have searched for Code 42 issues, and have come across some very useful information, which I have to the best of my ability tried to follow in the hope of eliminating my problem - but to no avail.

I’ll give as much info as I can, so sorry if this post ends up pretty big:

Situation:

I have a 95 RZ TT Manual that is BPU and came with a speedo converter / delimiter fitted (which I believe was purchased from a company called Import Solutions). I've had it just over a year and its been great - no issues with the car at all (apart from the cost of filling up lol).

I have recently removed my old boost gauge and an Apexi I-Monitor (some gadget that measures 0-60, etc). I have then fitted 3 gauges (boost, oil temp and AEM AFR).

Since then the MIL light has come on with a code 42 error (which I understand is speed sensor related).

Updated: 3rd December

It appears to happen at 60mph regardless of revs or whether im on/off boost.

I’ve never noticed any other lights flashing once the red triangle and MIL light have come on. The lights do not go out until I turn the ignition off. The car runs fine with/without the MIL light on.

Solutions on this Forum

From various code 42 searches I have come across the following possible causes:

:: Active Spoiler Issue:

My Active Spoiler has been unplugged at the ECU behind the radio since I purchased it. Since this problem has only happened since wiring in my new gauges, I’m not convinced it is responsible and I don’t know how I could further disable it.

:: Speedo Converter / Delimiter:

It has been suggested that this gadget could have ‘died a horrible death’ or a wire is loose. I’ve checked the wiring to make sure there are no loose wires (wires are soldered – the 2 crimped wires in the pic are now soldered). The speedo is working so I don’t think the unit is completely buggered if it is the cause. I could buy another one, but I’d like to try eliminating other possible causes first (ones that don’t cost a few bob lol).

:: Odometer Speed Buffer:

In the Code 42 Fix thread thread, it was suggested to splice the pink wire to the blue/red wire. However my pink and blue wires are already spliced in the speedo converter / delimiter (see pic). I didn’t fit the speedo converter/delimiter, it was on the car when I purchased it and as far as Im aware has been working fine for the year I’ve owned the car.

:: Dry / Dodgy Solder on the Odometer:

In the same Code 42 Fix thread, it was suggested that dry / dodgy soldering on the Odometer unit could be to blame. Short of forking out for a new ODO unit, I don’t know how I could confirm if this was the problem.

My New Gauges

Firstly, all the gauges are working fine, even with the MIL light on – so Im pretty confident I’ve wired them up right since the car didn’t burst into flames or anything.

All wires were soldered to the loom whilst the battery was disconnected.

The Boost and Oil Temp gauges take their power from the radio loom, so I don’t believe they have any relevance to my problem.

The AEM AFR gauge takes its power from PIN 1 (yellow / orange wire) of the ODO loom (see pic) since this was the only ‘Ignition Live’ I could find nearest the AFR gauge location (its in place of the dash clock).

Whilst finding an ‘Ignition Live’ for the AFR gauge, I did have the ignition ON with the top part of the dash (hazards / Odo / Warning Lights) unplugged, in fact I had all the dash panels unplugged as I was fitting a new dash at the same time.

Could this have any relevance?

I’ve read about problems with the airbag light staying on when you have the ignition on with the dash panels unplugged (although I haven’t had that problem).

Is PIN 1 for the Odometer an 'Ignition Live' source or something else? (I tested for ignition live using a gadget that resembles a screwdriver with a ground wire and a bulb, which lights up when you touch the tip of the ‘screwdriver’ to a power source).

If there is another possible cause that I’ve missed please point it out as I’ll look into it before admitting defeat.

UPDATE:

Problem Solved (disconnected PINK speed wire to ECU): http://www.mkivsupra.net/vbb/showthread.php?t=92818&highlight=code

Cheers

Simon