Good ol' Code 42 - no1 speed sensor

Hi All,

Apologies for the rambling post, but I want to tell you what I've already tried....

I've got a code 42 error that's come up recently. I've done several searches on here, but I've followed the advice of things to look for and nothing looks suspect. Does anyone have any ideas of things to try?

There are no other symptoms at all, other than the warning lights. The speedo seems to be working fine, and the odo still counts up OK.

I should mention that my speedo is in MPH, and the dial goes up to 180mph. From what I've read, this indicates that a speed conversion box-of-tricks has probably been fitted at some point. The odo still counts up in kms.

Here's what I've done:

1) Taken the dash panels off. I can't see a speed converter behind the speedo, but I don't really know what I'm looking for, other than a box thingy!

2) Had a look at the connections going into the ECU in the passenger footwell, paying particular attention to the pink wire. Gave the wire a GENTLE tug, seems fine. It doesn't appear to be tee'd off or anything out-of-place like that.

3) Had a look at the conenctions going into the odo. Again, all seems fine, with no loose or missing wires.

I haven't done any work on the car recently APART FROM some head unit work where I had to take the odo off, so that's still my number one suspect. No error code before taking odo off, error code first appeared a few weeks after putting odo back on.

I haven't done any electrical testing on the wiring yet: this is because I don't know what the expected results would be on, say, voltage tests. (I could still test for resistance to check the wiring continuity, haven't done that yet. It's quite awkward to probe some of the contacts though, not much bare metal showing).

Something that people have suggested in other threads is: fit a TRL speed converter. This still seems like a shot in the dark though, could be caused by something else.

Thanks in advance for any help received!

Steve

got exactly the same problem!

all wires seem to be intact.

any suggestions?

Hi risingsun (and welcome to this site! )

I've still got this problem. I haven't been able to track it down yet. I think I may need to put a multimeter on the speed sensor wire and drive around.

What are your symptoms? Does the speedo still work? Does the odometer still count up OK? The speed signal comes from the sensor itself (which isn't usually the cause of the problem), goes into the speedo (possibly via a speed converter if one's been fitted). From there, the signal goes into the back of the odo, which buffers it, and then sends it on to the ECU in the passenger footwell. Because my odo still works, I reckon the signal is getting lost between the odo output and the ECU.

Same here. Odo is fine, speed is bang on, cruise control is fine, ECU has been reset.

I have read somewhere that the odo units are getting to the age now where some are starting to fail. Even if the wires all seem fine, either their solder joints go bad, or similar.

If you've visually checked the wiring from the odo to the ECU, then if you know anyone local with a supe, try swapping the odo units over to test. To trigger the code, you'll most likely need to be driving at 60-ish MPH or over, for at least 8 seconds, with the engine up to normal operating temperature.

Does anyone get an engine management light with his or is that another problem? Does this when I give it a good kicking

By engine mangement light, do you mean the orange engine symbol to the right of the dash, or the red exclamation mark in the middle of the rev counter? - with a code 42, you should be getting both of these. The red one indicates a general warning or error, and the orange one indicates that the ECU has stored an error code.

I get both, which is what should happen (if you see what I mean...)

No red warning triangle (not since I topped up my power steering fluid) but the orange engine managment one. Puts my mind at ease a bit

A bit of a side issue, but I think you should get the red one lighting up as well. Does it come on when you've got your handbrake on? If not, the bulb's probably gone!

lol yeah the light works fine... it was coming on all the time with the low brake fluid (not power steering ilke I said earlier)

Had the exact same problem, replaced the Speed Converter with a TRL one from Thor and the problem has gone away

ODO, speedo ,etc was always counting fine, bar from the ECU and Warning light.

Thanks for the welcome guys!

Well did have both lights coming up but checked the brake fluid level as i know this is problem some times and now only the orange engine picture light comes on! tried ressetting and it still comes on exactly as you say if you give it a higher load for more than 8 secs.

do you know if this would affect clutch slippage and steering at all. because my steering feels incredibly light and almost dangerous!

thanks

forgot to say speedo working okay and odometr still clocking up okay too

Yeah, it would affect power steering since it is speed sensitive and if the ECU isn't getting the correct speed, your steering won't be made heavier, also your aircon will be acting weirdly..

Gav

hmmmm that'll explain me nearly killing a pensioned on the way back from Leeds on Saturday. Best get it checked out

probably expalins a few things then. car was idling really funny when a/c was on too.

sounds like we all got the same prob!

Had the exact same problem, replaced the Speed Converter with a TRL one from Thor and the problem has gone away

 

ODO, speedo ,etc was always counting fine, bar from the ECU and Warning light.

Imi, did your old speed converter used to work, or did you get the code 42 from purchase? Just seems weird that one day my box is working fine, then another day it just gives up!

Yeah, it would affect power steering since it is speed sensitive and if the ECU isn't getting the correct speed, your steering won't be made heavier, also your aircon will be acting weirdly..

 

Gav

Gav- Aircon acting weirdly ? explain please?

Imi, did your old speed converter used to work, or did you get the code 42 from purchase? Just seems weird that one day my box is working fine, then another day it just gives up!

Old converter worked FINE..

BAR from the ECU light and warning light - code 42 error

And once upon a time the steering wheel was very light.....but then this rectified itself on the old converter...

TBH - not sure why and how I managed to get it fixed, all I can say is that wtih the new TRL converter it is all working fine...

well seem to have stopped mine coming up with the engine light. i looked down by the ecu and for some raeson there were wires everywhere but specifically the pink one had been CUT!!

cconnected them back together and reset ecu. DA DAH! no engine light coming on now BUT steering is still extremely light. WIll this rectify itself and is there something i can to do reset that also?

Thanks

Nick

Nice work Nick! Glad you got it sorted. (You have driven it over 60mph with engine warm for more than 8 secs, have you?) Not sure about the power steering. Your symptoms now seem to indicate the ECU gets the speed signal OK, but then this possibly isn't being passed on to the PPS system. Someone else more helpful than me may be along soon...

TBH, I was a bit disappointed when I looked at my ECU and found the pink wire intact. It means I've got to continue my fault-finding. I may try re-soldering the contacts on the odo circuit board next: I can't see any breaks, but several peeps on mkiv.com have this problem and it's fixed it for them.

yeah def drove it over 60 for more than 8 secs and it still seems to be fine!(fingers Crossed)

i must admit i was quite relieved to see the pink wire chopped. I read on here somewhere that the cartek convertor can cause problems with the steering so that could be where my problem lies. surely there must be a way to correct this though without having to fork out for another convertor?

might be worth you giving the soldering a go on the odo. hopefully will do the trick as there may be a dodgy connection hidden in there somewhere.

Cheers

It could be that the cartek unit doesn't handle the PPS system very well. If you need a replacement unit, check out Pete Betts at Thor, his units come VERY highly recommended.

When you say code 42, I assume you first found this with the flashing O/D OFF light. I have this as well. Orange engine light upper right came on intermittenly there for awhile only when I'd get on the autoban and give er the gun for a bit. I haven't taken the dash apart yet as I was waiting on my TRD speedo, but it's in now. All I'm lacking now is the soldering iron and the balls to just do it without the worry of trashing the odometer. Damn, I hope it's the solder points. I'm sick of the light flashing and the light-steering. Nerve racking on the autoban at speed. The SLD from Thor is my next mod, and soon I think too. Let me know what you guys find out and I'll do the same. Peace-out.

First I knew of the error code was the orange engine light and the red warning light both appearing whilst driving. Mine's a manual so I don't have O/D. Visually check the wiring at the ECU and odo first before doing any soldering.