1st ever trip to garage on the horizon

cyclonebri1

In true MSE miserly tradition, I have yet to take a car to the garage for anything other than the mots.
But I'm stumped with this 1 so I may have to admit defeat and cough:eek:

Renault megane est, ABD and ESR and ASR warnings lit up.


If anyone can sense check this for me I'd appreciate it, (has also posted the same on a renault forum I use)

All wheels removed and sensors cleaned and wiring inspected, all looks well.

Reluctor? rings not visible, part of the drive shaft at the front and the wheel bearing at the rear.

Resistance of each sensor checked, all 12 ohms, there must be a diode in there as they are polarity sensitive.

Car lifted and an ac voltage check on all sensors whilst spinning wheels, no reading on either an analogue or digital meter. Checked either polarity.

After removing half the under bonnet and bulkhead arrangement, including the wipers, I finally gained access to the ABS ecu, it's part of the ABS hydraulic unit. Removed wiring connector, cleaned, and refitted.

OBD11 doesn't interrogate this ABS ecu, needs a more specialised scanner methinks.

As I un derstand it the ABS ecu checks the resistance of each sensor whilst stationary, in the 1st 2 seconds, then the output of them when on the move.
The light comes on whilst stationary.

Anyway, no better, car can be driven but brakes revert to non ABS operation. MOT failure of course.

So unless anyone has any ideas or something I may have missed it's a trip to the rip off specialists.

tedted

what is the year of your renault as you may have active abs sensors and not passive ones.if you have active sensors the tests that you did would not work as you need to scope them.if they are passive your tests are ok,does the abs light just come on and stay on or goes out and then comes on?

cyclonebri1

It's a 55plte car, the sensors are 2 not 3 wires. Unsure as to whether active or not, but the lack of output when turning the wheel has me foxed.

The abs light comes on, goes off, does the 2 second stationary check I presume, then the lights are back on.

Biketrials08

I know the following is really trivial but I spent some time messing around with sensors on my r53 mini due to ABS etc lights and all it turned out to be was low fluid level (it was above the min but the sensor set-up wasn't too aligned to that). So check the level and the associated sensor, you probably already did this first but sometimes we can over look the obvious?

cyclonebri1

Biketrials08 wrote: »

I know the following is really trivial but I spent some time messing around with sensors on my r53 mini due to ABS etc lights and all it turned out to be was low fluid level (it was above the min but the sensor set-up wasn't too aligned to that). So check the level and the associated sensor, you probably already did this first but sometimes we can over look the obvious?

It's a fair suggestion, I've read the same whilst looking into this, I did suspect it might be that as both the clutch and brakes share the same fluid reservoir. But it wasn't the cause.

Good news is, and this reinforces what I've always said about getting a relationship going with a decent non affiliated local garage, inspite of what I have read re the abs not being able to be read from the main ecu, it can be.
With there more advanced gadget than my standard scanner it showed all sensor circuits open, remember I had opened all connections and these had locked in.
Cleared and no lights on when stationary, took a quick drive and at about 20mph the lights back on.
Back to garage within 2 mins and connected up again and shows a duff LHS front sensor, must be missing the output when rotating, the test I couldn't get a reading from.
So, new sensor ordered and we will see.

Now the good news, I've only ever used these guys for the tests on our 2 cars, but the charge for the diagnostics and to clear the system when I've replaced the sensor was £20:T:T:T:T:T

forgotmyname

Some OBDII tools test the ABS system. But unless there is a box thats designed for your car it maybe several hundred £'s.

I have a box that connects to my car and it cost £40 when i bought it. But available for £20 now.

Nothing similar for yours?

cyclonebri1

forgotmyname wrote: »

Some OBDII tools test the ABS system. But unless there is a box thats designed for your car it maybe several hundred £'s.

I have a box that connects to my car and it cost £40 when i bought it. But available for £20 now.

Nothing similar for yours?

If you mean a maker specific add on (hope you understand), then no, I bought a standard scanner about 3/4 years ago, never had need of it until this. Hopefully the new sensor over £50 from the local factor but £18 del from the net will cure the issue.

I will report back to ensure closure

PS, like the sig, reflects my attitude:T

flang

Sounds to me like the fault may be with either the relay or the speed/acceleration sensor, have a go at re-seating them.

cyclonebri1

flang wrote: »

Sounds to me like the fault may be with either the relay or the speed/acceleration sensor, have a go at re-seating them.

Check post #5;)

atrixblue.-MFR-.

hi bri, you seem to have this one sussed, im a ren megane vet having owned a 54 1.4 and mate has a 1.9 DCI on a 55.

ABS LHS sensor is the first sensor in the curcuit, and is the usual suspect to ABS faults. but its not always the sensor, its the ABS ring either has a tooth missing, or is covered in gunk and film and rust that it cand read the risistance BTW its an active sensor, you have ESR wich is an active stability program, and you also have asr (trac control), the ABS will be ACTIVE sensors for these programs.

your handheld wont interrogate the ABS control ECU unit unless you have the renault clip machine, or a £150+ odb2 module and connectors, wich is a pain in the bum when you need to get it sorted.

if you get anymore problems pm me to bring the thread to my attention and ill help as best i can.

cyclonebri1

atrixblue.-MFR-. wrote: »

hi bri, you seem to have this one sussed, im a ren megane vet having owned a 54 1.4 and mate has a 1.9 DCI on a 55.

ABS LHS sensor is the first sensor in the curcuit, and is the usual suspect to ABS faults. but its not always the sensor, its the ABS ring either has a tooth missing, or is covered in gunk and film and rust that it cand read the risistance BTW its an active sensor, you have ESR wich is an active stability program, and you also have asr (trac control), the ABS will be ACTIVE sensors for these programs.

your handheld wont interrogate the ABS control ECU unit unless you have the renault clip machine, or a £150+ odb2 module and connectors, wich is a pain in the bum when you need to get it sorted.


if you get anymore problems pm me to bring the thread to my attention and ill help as best i can.

Hi and thanks, yes you learn quickly when a problem arises.
Been sat on the OBD11 for about 4 years now, never needed it and when I do it doesn't cover the whole spectrum, but for £20 at the garage I ain't too worried.

Sensor arrived this morning, too late to get it fitted and back to the garage. I am a little concerned as the resistance of all 4 originals was 12ohms, the new 1 reads 50ohm.
I don't think it is a toothed ring on my car, may be wrong but it appears solid to the eye, the variator is probably encapsulted in that ring. It will get a good clean out and fettle before I put it back together.
I do know from speaking to the local garage that they have found several diffent system on similar aged cars, some you have to replace the front drive shaft and some that are just a pressed on ring as you say.

And about the cars in general, this is a 55pte diesel est, the wife has a 07 diesel hatch, both bought at 1 year old.
No issues with either regarding reliability apart from this minor annoyance and dent to my pride in always bveing able to fix problems myself.

The car will be changed next year, and as Renault are now 3rd in the reliability stakes I have no hesitancy in going for another 1.

I will post the end result for the benefit of anyone interested.;);)