Peugeot 406 HDI (99 onwards) - ABS fault - ABS sensor

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Tue 5 Jul 2011 23:16
Peugeot 406 HDI (99 onwards) - ABS fault - ABS sensor - Whatdowepayourroadtaxfor

My ABS light comes on intermittently.

Have checked sensor continuity and output (with a digital multimeter from the ABS unit multiplug)

Three of them read 1.6Kohm and produce up to 0.5 volts AC rms, depending on the speed at which I spin the relevant jacked up wheel.

One of them (rear n/s wheel, read from pins 8 & 9) reads open circuit (no continuity) and no output (as expected) when the ABS fault light is on, but reads as the other three when fault clears.

An open circuit / no output reading could nean the sensor is genuinly open circuit or there is a break in one of the two leads that feed it.

Before I order a sensor, I noticed (from suppliers pics.) that the sensor assembly terminates from the wheel end in a two pin plug or socket which presumably connects into a wire loom that finds its way back to the ABS unit multiplug.

Obviousely this two pin plug and socket assembly could be the problem (as could the wiring loom!) rather than the sensor.

Can anyone shed some light on this...where the two pin plug/socket is situated, and how easy / difficult is it to replace the rear wheel sensor (and get at the two pin plug/socket to facilitate this) if the sensor turns out to be intermittently open circuit.

Thanks.

Edited by Whatdowepayourroadtaxfor on 05/07/2011 at 23:18

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Wed 6 Jul 2011 11:09
Peugeot 406 HDI (99 onwards) - ABS fault - ABS sensor - Peter.N.

I have had similar problems with XMs due to a poor connection on the plug. On the XM the plug is mounted on the top of the rear subframe and to have reasonable access you need to drop one side of the subframe, not actually to difficult if the 406 is similar. Just slacken but do not remove the bolts on the opposite side, support the side you are working on with a jack, remove the bolts and lower it. I don't know if it is the same but should be easier without a whole range of hydraulic pipes.

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Sat 9 Jul 2011 11:13
Peugeot 406 HDI (99 onwards) - ABS fault - ABS sensor - gordonb88

Pins 8 and 9 looks like its left rear. The rear abs sensor can get damaged by the shoe retaining pins when they pull through their holders and smash into the sensor tip and sometimes damaging ABS teeth. I would get under the car and do a continuity test at the plug to the sensor, to eliminate trunk wiring fault, It is easily accessable in the 406. If broken wiring is found these can be soldered but do require proper sealing.

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Mon 11 Jul 2011 22:54
Peugeot 406 HDI (99 onwards) - ABS fault - ABS sensor - Whatdowepayourroadtaxfor

Hi. Thanks for the response and advice. Much appreciated.

Where exactly is the plug and socket assembly so I can identify it to a friend to look at?

I used the term rear nearside so as not to confuse left with right.

It's the rear left looking to the front from the rear, and it's pins 8 & 9.

I only have the supplied jack so I can't really get under properly to look, however, my friend has the propper gear and I can point it out to him if you let me know.

By the way, the last people to change this tyre have overtightenned one of the nuts so I can't get the wheel off! (hope I don't get a puncture)

The friend also has a propper nut wrench. He's a useful friend to have. I'm good with the electronics, he's got the gear.

Thanks very much again. If I can find the assembly, I'll let you know the outcome, however, it's behaving itself over the past few days...dentist's syndrome, I think. I'll sneak up on it soon....

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Mon 5 Dec 2011 10:38
Peugeot 406 HDI (99 onwards) - ABS fault - ABS sensor - Whatdowepayourroadtaxfor

Problem now resolved and repaired.

Seems that Peugeot have a problem with wire looms in older cars. See my posting about 406 anti-pollution warning light / battery drain fault.

There was a very intermittent wire loom fault from the rear nearside ABS sensor plug / socket assemply to pin 9 on the multiplug on the ABS computer.

The loom goes in and out of the vehicle superstructure like a mouse in a labrynth, so was unable to find the exact break point.

Repaired by running a pair of wires (bell wire or cheap loudspeaker wire) along the vehicle underside (soldering into the wire at pin 9 of the multiplug on the ABS computer) to the relevant connection at the sensor end at the rear.

Why a pair of wires rather than one wire? Because it's as likely as not that there'll be another intermittent wire break in that loom and I might be able to utilise the redundant wire to fix it.

Thanks for all the help.

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Mon 5 Dec 2011 11:50
Peugeot 406 HDI (99 onwards) - ABS fault - ABS sensor - madf

I am glad to see my deep distrust of French wiring is justified.

Sounds like a clever cheap repair to me...

Edited by madf on 05/12/2011 at 11:50

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