[djbarber]

Got a 307 SW 204 plate. Had abs/esp fault for while. Followed advise found on forums. Traced wiring, found and repaired trapped wire that near ecu plug that fed left front wheel. Soldered the 2 wires together and heat shrunk joints to make water tight.

Cleaned ecu plug socket with degreaser and contact cleaner. Using icarsoft scanner discovered electrical fault with front left sensor after the repair was made. Also front right speed sensor coherence. Have replaced both front sensor with new ones. Electrical fault now gone. However both front now have coherence fault.

I have also scrapped rust residue on all 4 sensor housing wire brushed to almost shining finish. Had new rear disc and pads due to almost metal to metal and deep scoring. Had both front wheels in air, using toothbrush and degreaser whilst in gear was able to clean the front abs sensor area. Reassembled. ABS fault gone of dash. However, go few hundred yards comes back on. Using icarsoft scanner both front sensors read in coherence. On live data left front is zero the other 3 have readings of similar speed give or take half km/h.

I am unable to better the better the air gap, as all sensor areas have been cleaned, 2 new front sensors fitted (even swapped both front around). Only thing I can do is shave the sensor bracket to make thinner or shim them out to increase by using nylon washer

What am I missing? What would my next move be? I'm at wits end, taking me several days in hours spent but still not progressing any further. Any advise or pointers much appreciated

One thing i have noticed, not sure how relevant it is. But the redish plastic abs ring cover, there is a slight divet on right sight. On left side it looks like there is not plastic cover, However still approx 1mm space. Would this make any differance

 

[madbadandold]

The front sensor not reading could be the trigger plate for the sensor. This is part of the wheel bearing and so the wheel bearing will need replaced. It is not easy to replace the bearing alone but a might easier if you can get a good known hub assembly from a scrap yard. See my thread reference the bearing replacement.

 

[WillNZ]

Check the plug on the ABS ECU for corrosion. Check ABS ECU for water damage.
Get the sensor closer to the reluctor ring. Make sure reluctor ring is clean.
Check wheel bearings do not have play, replace if they do.

What year is a 204 plate?

 

[djbarber]

Thanks for advice i shall look at these.

WillNZ - typo should be 2004 plate 04 year. How do i get sensor closer to reluctor ring? Its fully home in housing area with bolt tight. Only thing i can think off is to shave the bracket thinner, thus bringing the sensor part closer.

 

[madbadandold]

See my post about reluctor ring. If it has damage as you say then that is the culprit. Wheel bearing change!

 

[WillNZ]

Not sure as mine is a pre-facelift model and yours has different sensors listed to mine, so mounting possibly differs. If the mounting surface is perfectly clean and free from any damage that would prevent the sensor from seating properly, then it should [theoretically] be ok. But then it is a Peugeot....

try the other things I listed first. You can also use a multimeter on ohms and measure the resistance of the two front sensors to see if they are the same. But this is a long shot as they are basically passing the test on starting as the abs light goes off, and only comes on when moving, which normally means they are within initial spec. [but still does not guarantee they are not faulty].

The 307 is known to be prone to water damage to the ABS ECU due to its positioning, so have a careful check for corrosion/water.

If a wheel bearing is loose, it will allow the reluctor ring to move away from the sensor and not allowing the ring to interact with it, so make sure the bearings are ok.

If there is any damage to the reluctor ring, replace it.

 

[monty9120]

you need to see if the back of the wheel bearing is still present. its magnetic so as long as the bearing hasnt been put in the wrong way
first of all check the connectors

on the fronts the sensor design is alot better. they fit and thats it

what side isnt working. front left normally does the speedo

 

[madbadandold]

The best way to check is with live data. If the front right is the culprit then there will be no increase in wheel speed at that wheel as was mine. All three others were ok on the first live data check but that was done at walking speed by a garage. After I replaced my front bearing the ABS showed failed with left rear coherence. Live data showed that all wheels were indicating but the left rear was all over the place. A eyeball check revealed that corrosion had pushed the sensor away at an angle and so it was removed and thoroughly cleared of dead steel and refitted and bingo job was a good un. At last!