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Ist gear switch question...

1K views 40 replies 7 participants last post by  Jamie C 
#1 ·
Ive had an ECU code keep coming up, was the code for first gear boost cut switch.

Now today i disconnected the switch and no faults anymore but, does the car now think its in 1st all the time as the plug is no longer connected to the switch or will it never register 1st gear? Dont know which way round the switch operates and was too late to check it.

So do i have to bridge the two wires together to make the car think its outta 1st or shall i leave em unconnected from each other?

Ta, Jamie.

:beer:
 
#28 ·
sb_scottmonkey said:
Sounds like your swith contacts have got filthy. Guess it's a sealed unit, so no chance of cleaning them - worth changing it man.
BASStra said:
Aaaaaagh, nnnnooooooooooooooooo!!!!!!!!!!!!!

Fitted new switch today..........
;)

Thanks scott, so the br is straight to earth not back to ECU, all i can test this for is acceptably low resistance then, and the same for the ECU to switch wire as well. As long as both are acceptably low resistance then thats the wiring checked innit?

Spose i can clean the terms up on the wires where they plug to the switch as well.
 
#29 ·
Aaaaah feck, tested wiring yesterday, 0.06ohm in each side of circuit, cleaned terminals, chopped out and replaced a bit of the earth that looked a lil ropey, reset ECU, took car out. 15 mins later, BING, ECU light on again. Code 41 :(

Any other ideas fellas?

Could it be ECU or chip related?
 
#32 ·
Andy, when i disconnected the switch and left the plug unbridged that would give the ECU the impression that i was in first, agreed? But didnt get an EM light up, even at a steady ton in fifth/sixth.

Why would the ECU not have sussed from the speed signal and RPM signal that the vehicle was not in a higher gear and therefore logged a fault?

Puzzling...
 
#34 ·
So if the speed input was dead then no fault code will come from removing plug and leaving unbridged, right?

So why a fault code from having plug bridged, assuming speed signal is dead?

Ta, Jamie.
 
#36 ·
Sorry, i know its dragging a little, lack of performance in the car is driving me mad though.

OK, what am i looking for when i check the speed signal wire, will pull out fuel comp and check it tonight maybe. Which wire, what reading to expect from it.

Ta.
 
#38 ·
Thanks Andy, u the man, will check it out, have left it with the g/f at the min and pinched her vectra.

I really hope it is that speed signal, driving me up the wall now.

:beer:
 
#39 ·
Noooooooooooooooo!!!!!

Just been out for half hour driving, passengers eyes glued to fuel comp. So displayed whole time, ECU light still came on though, same fault. Depressing.

so what next?
 
#40 ·
It was over 2 years ago that I did mine but heres my 2p worth.
I may not get all this right by the way.
As soon as I put the Engine in the Mk3 from the Mk2 I got this code, never had it in the Mk2 as it uses different signals from the dash.
To get rid of it I cut and bridged the wires from the switch, this then gave me 3/4 boost in all gears i think, so the next step was to cut one of the wires in the footwell, you remember the 3 blocks down their, fuel pump, rev counter etc , well I cut one of these and everything has been perfect since. no Management lights and full boost.
Sorry that I cant remember the wire, it was 2 years ago, blue with red tracer rings a bell but not 100%..

Hope I helped a little

Regards Bren
 
#41 ·
Well, today i ripped out the ECU, and changed the chips back to the VanAken and MX chips that id previously taken out to put the standard chips in.

Guess what? NO EM LIGHT! Hurrah!

Musta been an iffy set of chips, will get another set and try again.

But having the 'performance' chips back in is nice, lotsa extra power found.
 
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