23 replies to this topic

[Hark]

ABS light was coming on intermittently but is now on all the time. ABS doesn't trigger at all. Yesterday was the first drive in 3 months due to a badly broken arm. Speedo was intermittent, reading correctly and then dropping to zero. Abs light still on. Today Ive checked the NSR hub connector. Both wires look intact and no obvious breaks or corrosion. Cleaned connector block with contact cleaner. Fuse 22 looks fine. Speedo is now working ok but this could be fluke. What else can I check? I could change the fuse to rule it out. Is it possible speedo could be a gremlin from not being used in 3 months and the abs relates to a different hub sensor?

[peteslag]

It must be related to your NSR hub sensor. My old VXT had a broken wire and gave the exact same symptoms as yours. Is the ABS light still on?

[Kieran McC]

Check thehub sensor. If you have a Opcom try that it may clear the fault.

[peteslag]

The code on mine cleared as soon as I fixed the fault, I didn't need OPCOM. If you need to use OPCOM I have it.

[Hark]

Yes light is still on.

 

Don't have OPCOM and never used it before.  Whenever I've had a fault before, once I fixed the issue the light cleared itself. 

 

There is only one electrical plug on the hub so I'm presuming that this is the hub sensor?  Two wires to the connector block and 2 from that to the hub.  None look obviously broken or damaged. 

[Kieran McC]

You will need to take the car for a run, it seems to clear it after reconecting the wires.

[Hark]

You will need to take the car for a run, it seems to clear it after reconecting the wires.

 

Yep, done that. No change . 

[Kieran McC]

Have you checked the loom abs wiring ? could be loom of doom ,

[Hark]

No.  Is that the loom behind the header tank?  And those big connector blocks there? 

[Kieran McC]

No.  Is that the loom behind the header tank?  And those big connector blocks there? 

The wiring to check is near the abs unit it is under the bonnett drivers side.

[Hark]

Ahh alright.  I've got 4 channel ABS, had a look tonight at that as well.  Will remove and reseat connector block, but gave the wiring from the connector block till it goes past the brake servo a quick once over and nothing obvious. 

[Kieran McC]

Ah has the abs unit been set by a lotus dealer, it may need reset just a thought.

[Hark]

Yea I bought it coded.  Worked on the road and track for over a year. 

 

This all started when I fitted ATS DTC Rims and had my Quantums fitted.  I was expecting to see the ATS had rubbed through a wire but nothing that obvious.

 

I'll keep looking and I'll check all 4 sensors.  Cheers for the help.

[myles]

Doesn't changing wheel sizes affect the 4 chan ABS?

[Hark]

Its coded for 17s I believe but either way it was excellent even with the ats dtc fitted. Never had any issues with it and that wouldn't have caused a speedo issue anyway.

[myles]

Tis true! Hope you sort it.

[Pidgeon]

Both sides on mine, the wires had corroded internally which resulted in a poor connection.  There's an excellent thread on here somewhere that correlates the wire numbers in the ABS unit connector to the respective wheels, but as you have the speedo issue as well you know it's N/S/R.

 

You are lucky if you find an obvious break, if not cut the wire from the chassis clip and open up the sheathing.  I bridged the wires at the connector and put a continuity tester on the hub end and manipulated the wire until I found the break.

 

Probably easier to trace the wire into the engine bay, cut and solder in a new length.  The connectors are available on the Bay for a couple of quid.

[Hark]

Chap replied on my facebook and set he could use laptop to check which hub for definite. Speedo all fine last night and today....

[smiley]

Chap replied on my facebook and set he could use laptop to check which hub for definite. Speedo all fine last night and today....

 

You can check that yourself with a multimeter on the abs plug.

[Hark]

So multimeter in test mode I'm presuming and then just across each pair of contacts for each sensor? The red and white arrows each end what are they??