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Code 42 Fix


Dave

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  • 2 weeks later...

Hi guys,

 

Yes, code 42 is often due to a dodgy odometer. I think the soldering goes dry on the odo circuit board or something. Dry solders can be very hard to trace! There are other things that can cause code 42, but this is the main one. If it's a dodgy odometer, new ones are very expensive from Mr T (several hundred pounds I think).

 

You can get a second-hand one, but 1) who knows when the soldering will go dry, and 2) until someone can sell you one, you'll be driving around in a car who's engine warning light will be lit 80% of the time.

 

When my odo did this, I bought a converter/TSD from Thor, and in the fitting instructions is how to bypass the odo's speed buffering. Bypassing the buffering doesn't seem to have an adverse effect on the progressive power steering (i.e. still works as it should do).

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Hi guys,

 

 

When my odo did this, I bought a converter/TSD from Thor, and in the fitting instructions is how to bypass the odo's speed buffering. Bypassing the buffering doesn't seem to have an adverse effect on the progressive power steering (i.e. still works as it should do).

 

 

hey steve, can you post those bypass instructions...?

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  • 3 weeks later...

Try this link guys:

 

http://homepage.ntlworld.com/peter.betts/supra/TechTips/speedo.htm

 

Hodge: a bit of background for you. The electronics in the supra's odometer unit can play up sometimes, and the symptoms you get when it does this is a speed sensor error (code 42). However, this is only the ECU's interpretation of what the problem is. In my experience, the speed sensors themselves very rarely need changing, and the problem usually lies in the odo.

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Try this link guys:

 

http://homepage.ntlworld.com/peter.betts/supra/TechTips/speedo.htm

 

Hodge: a bit of background for you. The electronics in the supra's odometer unit can play up sometimes, and the symptoms you get when it does this is a speed sensor error (code 42). However, this is only the ECU's interpretation of what the problem is. In my experience, the speed sensors themselves very rarely need changing, and the problem usually lies in the odo.

 

 

stevie, thx for the link, where is the section about bypassing the buffering of the odo?

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Yeah, sorry guys! The linked page doesn't really explain what to do. Click on the link labelled "Here's the schematic" to bring up a circuit diagram of the plugs and wires of the speedo system. I'm 90% sure that the "speed signal input" pin on the odometer plug is pin 5, and the output pin is pin 6 (i.e. the re-transmitted buffered signal).

 

If I'm correct, what you'll need to do is strip some of the insulation on the pin 5 wire, cut the wire to pin 6, and solder the loom side of the "pin 6 cut" to the exposed pin 5 wire. This merely bypasses the buffering of the odo unit.

 

This is from looking at the diagram on the web: I'm fairly certain of what I've written, but I'll try and dig up a diagram at home to confirm it. If I don't post on this thread again in the next couple of days, please remind me!

 

Steve

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Yeah, sorry guys! The linked page doesn't really explain what to do. Click on the link labelled "Here's the schematic" to bring up a circuit diagram of the plugs and wires of the speedo system. I'm 90% sure that the "speed signal input" pin on the odometer plug is pin 5, and the output pin is pin 6 (i.e. the re-transmitted buffered signal).

 

If I'm correct, what you'll need to do is strip some of the insulation on the pin 5 wire, cut the wire to pin 6, and solder the loom side of the "pin 6 cut" to the exposed pin 5 wire. This merely bypasses the buffering of the odo unit.

 

This is from looking at the diagram on the web: I'm fairly certain of what I've written, but I'll try and dig up a diagram at home to confirm it. If I don't post on this thread again in the next couple of days, please remind me!

 

Steve

 

the pink wire is the speed sensor wire in the blue/red wire is the out{ 99% sure} i joined the pink wire from the loom side to the blue/red and my speedo was all over the place .then cut the pink wire you have two bits one from loom one from multi plug. tape off the loom side and join the bit coming from the multi plug to the blue/red wire in the next pin. cant post any pics cause i taped it all up. and no probs since

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according to this diagram the pink wire from the multi plug {odo} is not joined to anything am i right and the loom side pink wire is attached to the BLUEWIRE is this diagram just the normal wiring for a delimiter or does it include the code 42 fix ???????? im confused now:(

as ive now developed a new problem with the speedo going on/off if i tap the odo case it comes back on ive either got a dry joint or my odo is foooked

dsc_speedo_mph.jpg

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Im all confused now. I thought that a flashing o/d light was the speed sensor fault, or is this another problem. As mine was doing this for the first time the other day then its gone off again.

Whats it all about.

 

yeah my o/d light was flashing too but not all the time this fixed that prob as well i think the three are all linked somehow

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Yeah the problems are usually linked. The speed sensor sends the speed signal to the speedo dial, from there it goes to the odo, and from there it gets sent to the ECU which controls the progressive power steering, active spoiler, etc. If this sequence is broken at any point (usually on the odo circuit board), then the active spoiler, /o/d system and PPS will stop working properly. If your odo ticks up the miles or kms OK, then you can be sure that the speed signal reaches as far as the odo input

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according to this diagram the pink wire from the multi plug {odo} is not joined to anything am i right and the loom side pink wire is attached to the BLUEWIRE is this diagram just the normal wiring for a delimiter or does it include the code 42 fix ???????? im confused now:(

as ive now developed a new problem with the speedo going on/off if i tap the odo case it comes back on ive either got a dry joint or my odo is foooked

 

That sounds right. The pink wire from odo plug (pin 6) is the output of the odo unit. If the odo's buffering is screwed, this wire won't carry a signal. So it's cut and an alternative signal (blue wire) is fed into it from the speed converter. Essentially, the diagram shows the output from the odo being discarded and instead an alternative speed signal (blue wire) is used.

 

However, sounds like you've got a dry solder there.

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i joined the pink wire from the loom side to the blue/red and my speedo was all over the place

I think that's because you're trying to feed two signals to the ECU on the same wire, which it won't like. :) One signal from the odo output, and another from the odo input.

 

then cut the pink wire you have two bits one from loom one from multi plug. tape off the loom side and join the bit coming from the multi plug to the blue/red wire in the next pin. cant post any pics cause i taped it all up. and no probs since

Not sure how the odo gets the speed signal input if you've done that. It can only get it from pin 5, and that's been cut and joined on the loom side to the output. This would allow the ECU to get the correct speed signal, but does your odo still count up as you drive?

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I think that's because you're trying to feed two signals to the ECU on the same wire, which it won't like. :) One signal from the odo output, and another from the odo input.

 

 

Not sure how the odo gets the speed signal input if you've done that. It can only get it from pin 5, and that's been cut and joined on the loom side to the output. This would allow the ECU to get the correct speed signal, but does your odo still count up as you drive?

 

it works fine with the mutli plug side of the pink wire connected to blue red wire-- doesnt this bypass the speed sensor no1

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Well I'm really confused now. How can the PAS,Cruise Control and Active Spoiler work correctly when their signal wire (pink) is cut and not connected to anything?

 

I don't see how joining the pink to the input achieves anything if the pink is the output from the odometer.

 

Is there another output to the PAS, Cruise Control and Active Spoiler?

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