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Marc Webster
Marc Webster,
Category: Heavy Equipment
Satisfied Customers: 227
Experience:  mechanic at sw autos
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I have an American RV and I'm looking for assistance on

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Hi. I have an American RV and I'm looking for assistance on diagnosis of an ABS fault. Can you help? Tony
JA: What is the complete model and serial number of your machine?
Customer: It's a Tiffin Allegro 32BA 2005. The VIN serial/chassis number is: *****************
JA: Are you fixing this yourself? What have you tried so far?
Customer: Not fixing it myself. It failed it's MOT test today on an ABS fault light unfortunately. It was fine otherwise. I have a local garage who I hope can fix the problem but they need to know precisely what is causing the ABS fault light on the dashboard and they do not have the diagnostic equipment.
JA: Anything else you want the Equipment Mechanic to know before I connect you?
Customer: It is on a Chevvy Vortec Chassis, petrol

Hello, usually 9 times out of 10 the fault will lie with the ABS sensor in one of the wheels, when this fails it will not send a signal or it will send a false signal causing the light to illuminate, it would be hard to diagnose without any equipment but we can start with the basics, does it come on and off or is it on permanantly.?

Customer: replied 2 years ago.
It is intermittent, sometimes on, sometimes on. Unfortunately it came on for the MOT ��
Customer: replied 2 years ago.
Sorry, happy to talk to you but not for £16. Can we not liase by email?

It does sound like a wheel sensor then, if the fault lied in the ECU it would be on permanantly,
i would advise the garage to check the ABS sensors, most garages should carry a kit that can diagnose this,
and it automatically requests a phone call, please ignore that. it is not necessary here,

Customer: replied 2 years ago.
Sorry I meant sometimes on, sometimes off

Its ok, if teh garage doesnt hold the kit to test abs speed sensors they can sometimes loan them from another garage, or you will have to take the vehicle to a different garage,

Customer: replied 2 years ago.
I am in Deal in Kent, the MOT was carried out this morning at Woods Commercial Services in Aylesham. They say they do not have the diagnostic equipment to investigate the abs sensors as it is a specialist American RV. Do you know of anyone near me who does have this kit?

I am not local to kent so i cant recommend any, a reputable HGV/ Commercial garage should definitly have the ABS test kits , they are the same for any vehicle as the probes push into the sensor , my only other advice would be to check local commercial garages near you if they have the kit, .

Customer: replied 2 years ago.
Ok I will do some enquiries for commercial garages with ABS Test Kits. Are you sure that they are the same for any vehicle? Even one manufactured in America?
Customer: replied 2 years ago.
Also will the garage have to remove the wheel and brakes etc etc to test the sensor, or is it a relatively straightforward test to see which sensor is faulty?

Yes they all work the same, they measure speed and send a signal voltage back to the ECU that works out how fast the wheels are turning and weather they have locked up or not, the kit comprises of a device that can either plug into the sensor (common manufacturers) or for exotic / foreign vehicles theres an adapter that has 2 small pins you can push into the sensor connectors, you then rotate the wheel by hand quite fast a few turns then monitor the signal , the kit also tests the ring that the sensor reads to make sure the ring isnt cracked or rusted over, this can be a common problem but its more than likely the sensor.

the garage may have to go underneath the vehicle or remove some trim panels to locate the sensor wiring plug, and to replace it the wheels will need to be removed.

Customer: replied 2 years ago.
if they do find the faulty one is it simple to mend it or would they need to order a new sensor and then fit it?

it would be wise to fit a new sensor

Customer: replied 2 years ago.
The wheels but not the brake assembly??

the abs sensors are located in the wheel HUb, the ring that the sensor reads is located in the back of the hub, most of the time on the brake disc, and im unfamiliar with the vehicle you own but it shouldnt be a major job to change.

Marc Webster and other Heavy Equipment Specialists are ready to help you
Customer: replied 2 years ago.
OK thank you Mark. I'll give you 5 stars. Goodbye for now. Tony

Thanks Tony, i hope you get the RV sorted asap, thanks for contacting me. Marc