Mk3 Cavalier Owners Club | Vauxhall Cavalier Dot Com

my (s) light keeps coming on during driving, but if i stop and turn off for a few minutes and start again, it drives normal. all the manual gears work and it's maybe once or twice a day, any ideas what it could be

Hi, I presume you mean the amber colored S with a gear like circle around it, that's on the automatic models, when you say all the manual gears work, you mean that you move the gear lever down and up throughout the range.

The flashing light indicates some sort of electronic fault within the transmission system, 9 times out of 10 it means that your selector switch (mounted on top of the transmission) needs taking apart and re-greasing, in most cases this will resolve the issue, if it's never been done before.

There is a way you can diagnose the problem with a paperclip, there should be a guide on this forum somewhere, you short out 2 pins on the diagnostic plug in your engine bay and the S light will flash out a certain error code, that will tell you the source of the problem.

Yep - this is the diagnostic test and codes.

To get the "S" light to flash out the fault codes, short pin A to pin C on the diagnostic plug,  turn on the ignition - engine not running.

17 Solenoid 1-2/3-4 (Voltage Low)
21 Throttle Position Sensor (Voltage High)
22 Throttle Position Sensor (Voltage Low)
23 Coolant Temperature Switch (Voltage High)
25 Solenoid 1-2/3-4 (Voltage High)
26 Solenoid 2-3 (Voltage Low)
27 Connection Solenoid 2-3/Solenoid TCC
28 Solenoid 2-3 (Voltage High)
29 TCC Solenoid (Voltage Low)
31 No Engine RPM Signal
32 Pressure Regulator Solenoid (Voltage Low)
33 Pressure Regulator Solenoid (Current High)
36 TCC Solenoid (Voltage High)
38 No Transmission Input RPM Signal
39 No Transmission Output RPM Signal
41 Gear Error Hydraulic Fault (usually an internal transmission mechanical failure -  forward clutch ?)
42 Pressure Regulator Solenoid (Short Circuit)
47 Down Shift Protection
48 Battery (Voltage Low)
49 Battery (Voltage High)
56 Selector Switch (Incorrect Signal)
65 AT Oil Temperature Sensor (Voltage High)
66 AT Oil Temperature Sensor (Voltage Low/High)
67 AT Oil Temperature Sensor (Voltage High)
75 Transmission Switch (Voltage Low)
76 Engine TPS Load (Signal Incorrect)
77 Kickdown Switch (Voltage Low)
78 AT Shift Time (Too Long)

done what you said and did the paper clip idea and got these codes


12 - ???
28 - solenoid 2/3 high voltage
56 - selector switch (incorrect signal)
77 - kick down switch (voltage low)

The code 12, or one flash, two flash (x3), is just the default code, all that tells you is that the ECU has begun the diagnosis, it will flash out code "12" at the start and end of the diagnosis, anything in between will be actual error codes stored in there.

I've read on your other thread that you've removed and cleaned the selector switch unit, good work, assuming you put the brass pins back in there correctly, with fresh heat-resistant grease, that should in theory have solved the problem. It could just be that the ECU hasn't "cleared" the error code for the selector switch, I think there is a way of clearing fault codes, can't remember exactly how, but Robsey or someone else should know in detail.

As for the other 2 codes you got, not sure, kickdown switch, if it works as it should, then it could just be a dodgy sensor somewhere, again someone should help you there in more detail.

Regards.

To clear the codes, simply disconnect the battery or pull the fuses.

This will work for all modules except the airbag system.

High voltage / low voltage situations usually refer to a dodgy connection.
Can't remember which way round it is, but one is caused by dirty or poor connection.
The other is often a short to earth.

As Andrei hinted...
If the codes remain 'after' clearing by disconnecting the battery,
Check the pins etc in the selector switch mechanism on the box.
Make sure they are fitted correctly.

Test again and if this still fails to sort the issue, look at the connector to the switch.
Clean any corrosion or moisture from the pins in the connector and socket.
Then check for chaffed or damaged wiring in the loom to the selector switch.

Thanks guys. I’ll give the battery disconnect ago tomorrow and see if it resets the problem then go from there.

Disconnect battery and reset Ecu........ followed by a drive, after 14 miles and temp at 95 the flashing “s” returned. Returned home and did paper clip short. Following faults

28 - solenoid 2/3 high voltage
56 - selector switch (incorrect signal)

Reverse light works fine so I’m running out of ideas. Anyone want a cavalier ?????? Lol

Sounds like a thorough check, clean and possible repair of all the connector pins and wiring as far as you can trace them, starting at the selector switch and working out from there.

Not sure, but I seem to think someone mentioned that the autobox ecu was behind the glovebox in the cabin of the car.

You could check this too. (Connector pins and wires).
However I suspect the harsher environment within the hot and mucky engine bay would make the selector switch assembly the most likely culpret.

I am not sure if you have a Haynes manual,
But just in case the switch is set up wrong.

Here is what Vauxhall tell their technicians.

Removing the switch





Adjusting the switch



Setting the switch





Final tightening torques



I hope that helps.

I am sure the switch is set up correctly, as you get the reverse light when you should.

so it brings me back to checking the wiring and connectors.

Robsey wrote:I am sure the switch is set up correctly, as you get the reverse light when you should.

so it brings me back to checking the wiring and connectors.

Yeah, all the gears work in every position fine ie reverse, park, neutral etc

The problem happens after a few minutes of driving, around the 10 /15 miles mark and when the temp is up to around 95c. All of a sudden it comes on.

I ran it this morning for about 6 miles and nothing came on, it was fine

Sounds almost like a high coolant temperature issue, however no temperature related code is flashed up.

Although to be honest 95 degrees is a "normal" engine temperature.
About the same point above which the radiator coolant fan might cut in.

Robsey wrote:Sounds almost like a high coolant temperature issue, however no temperature related code is flashed up.

Although to be honest 95 degrees is a "normal" engine temperature.
About the same point above which the radiator coolant fan might cut in.

I’ve checked the switch, changed the oil in the auto box (which to be fair was bad), checked the connectors (only looked at and blew into) and took it for a spin........ flashing “s” again...... it’s got me baffled. Just disconnected battery to reset it and will give it another run tomorrow. Can I ask, does it do any harm if the flashing “s” comes on and I have to drive it in 1,2,3 and d ?

I had that issue on my old auto and while waiting to source a replacement selector switch, I drove the car manually (shifting the gear lever by hand) for a couple of months or so.

It made some weird whining noises, kind of like a robotic arm motor, if that makes sense, and it made bumpy gear changes, like when you lift a clutch pedal up too quick while shifting gears, but after replacing the selector switch and a couple of fuses, it was smooth again in automatic mode. That was my own experience, in theory you should be ok shifting manually for a while, but be careful while shifting up to N from the gears, as once I over-shot it by a click and hit R while driving at 20mph. Thought I completely blew the transmission, but restarted the engine and she went on her way as normal. Was super-surprised that I didn't nacker it right there. And until I got rid of the car, the transmission was perfectly fine.

I still think your selector switch could be throwing up the error light, I would really double-check it inside, to make sure the pins are in the right place and everything is nice and secure.

Cavalier342 wrote:I had that issue on my old auto and while waiting to source a replacement selector switch, I drove the car manually (shifting the gear lever by hand) for a couple of months or so.

It made some weird whining noises, kind of like a robotic arm motor, if that makes sense, and it made bumpy gear changes, like when you lift a clutch pedal up too quick while shifting gears, but after replacing the selector switch and a couple of fuses, it was smooth again in automatic mode. That was my own experience, in theory you should be ok shifting manually for a while, but be careful while shifting up to N from the gears, as once I over-shot it by a click and hit R while driving at 20mph. Thought I completely blew the transmission, but restarted the engine and she went on her way as normal. Was super-surprised that I didn't nacker it right there. And until I got rid of the car, the transmission was perfectly fine.

I still think your selector switch could be throwing up the error light, I would really double-check it inside, to make sure the pins are in the right place and everything is nice and secure.

Thanks pal for the advise. I will investigate the selector switch again. It would be great if you could get a new part for £50/£100 instead of £300 odd.

I managed to find one eventually from some breakers site, think it cost me around the 50 mark, ( can't remember which one) but nowadays I wouldn't like to guess how hard it is to find one.

In these cases it's always worth poking around and getting your fingers mucky before spending cash on replacements. Keep us posted on this mate.

Cavalier342 wrote:I managed to find one eventually from some breakers site, think it cost me around the 50 mark, ( can't remember which one) but nowadays I wouldn't like to guess how hard it is to find one.

In these cases it's always worth poking around and getting your fingers mucky before spending cash on replacements. Keep us posted on this mate.

Fingers crossed I can fix this one. It’s a 70k mileage one so hopefully it’s got a little life left in it.

70.000 miles is nothing. My old auto had roughly that when I bought it, I got it to well over 100.000 by the time I got rid of it, with basic maintenance and replacing parts here and there. If you look after them, they will last ages.

Cavalier342 wrote:70.000 miles is nothing. My old auto had roughly that when I bought it, I got it to well over 100.000 by the time I got rid of it, with basic maintenance and replacing parts here and there. If you look after them, they will last ages.

There’s hope then. I’ll be honest. I was given the car by a family member to take part in a rally to Monte Carlo and back. I’m hoping to get it through the 2k mile trip then I’ll happlier donate the car to anyone who needs parts etc or would like to keep the diplomat running. I just could bring myself to see it scrapped as it’s a nice car....... apart from this bloody “S”

Oh trust me, none of my 3 old Cavaliers ever passed an MOT first time, they always needed welding or some other stuff fixing, but I stuck with them, there's just something about these cars that makes owners dig in and keep them going. We've all been there mate, niggly issues are just that, there is always a way of sorting them out. There are Cavaliers out there still with over 200.000 on the clock and still going strong. Every car on the road has or will have issues, it all comes down to how you feel about the car, and how much you are prepared to keeping it going. Repairing and maintaining an older vehicle in my mind will be more cost effective than buying a new piece of plastic which depreciates faster than Paris Hilton. Get that selector switch a second look and go from there.

Cavalier342 wrote:Oh trust me, none of my 3 old Cavaliers ever passed an MOT first time, they always needed welding or some other stuff fixing, but I stuck with them, there's just something about these cars that makes owners dig in and keep them going. We've all been there mate, niggly issues are just that, there is always a way of sorting them out. There are Cavaliers out there still with over 200.000 on the clock and still going strong. Every car on the road has or will have issues, it all comes down to how you feel about the car, and how much you are prepared to keeping it going. Repairing and maintaining an older vehicle in my mind will be more cost effective than buying a new piece of plastic which depreciates faster than Paris Hilton. Get that selector switch a second look and go from there.

Wish me luck and I’ll keep you posted over the next few days. I will beat this flashing “S”

We have a result !!!!
After changing oil, resetting ecu and a realignment of auto selector switch (just to make sure it’s in the correct position) ....... we have no flashing “s” after 50miles test driving.

Fingers crossed it’s fixed but thanks to everyone who commented and help with your advise. Really appreciate it

Excellent news, let's hope it stays that way, does she drive smoothly again now?

Cavalier342 wrote:Excellent news, let's hope it stays that way, does she drive smoothly again now?

Drives a dream. Thanks for your help