BIL N KEL

Is there any way of finding which abs sensor is faulty on my saff cos without the hassle of changing them 1 at a time?
Thanks Billy

PeterRST

iTrader: (1)

Unplug the plug that goes into your ABS ECU behind the dash. You can then measure sensor by sensor at the respective terminals of the plug. Have a look at a wiring diagram to see which is which. Or if you can take a photo of the pins of the plug I can mark them for you.

Best to measure voltage (AC!) which should be 0.1 - 0.2V when rolling and about 0.5 - 0.7 at 25 mph. You can either do it while a mate is driving or jack the car up, turn each wheel and note the readings.

BIL N KEL

Cheers mate I'll give it a try later. Has the ford cosworth workshop manual got wiring diagrams in it?

jon@work

iTrader: (5)

WHEEL SENSOR TESTS

All tests performed with ABS ECU unplugged and ignition switched OFF unless stated otherwise.


Sensor Resistance Tests
-- Connect ohmmeter as described:

• for RH rear sensor, connect ohmmeter between ECU connector terminals 4 and 22
• for LH rear sensor, connect ohmmeter between ECU connector terminals 6 and 24
• for RH front sensor, connect ohmmeter between ECU connector terminals 7 and 25
• for LH front sensor, connect ohmmeter between ECU connector terminals 5 and 23

-- Correct result is resistance for each sensor ranging between 800 and 1400 ohms.
-- If value is not correct, unplug each sensor (in engine bay or under rear seat) and check sensor for resistance between 800 and 1400 ohms at sensor connector. If sensor resistance not OK, replace sensor. If sensor resistance OK, check wiring for continuity between sensor connector and ABS ECU connector.

Sensor Voltage Tests
-- Connect voltmeter, set to measure AC volts, as described:

• for RH rear sensor, connect voltmeter between ECU connector terminals 4 and 22
• for LH rear sensor, connect voltmeter between ECU connector terminals 6 and 24
• for RH front sensor, connect voltmeter between ECU connector terminals 7 and 25
• for LH front sensor, connect voltmeter between ECU connector terminals 5 and 23

-- Check AC voltage while rotating the wheel of the sensor concerned at approx 1 rev/sec.
-- Correct result is voltage between 100 and 350 mV for the front sensors and 100 and 570 mV for the rear sensors
-- If value is not correct, check the sensor installation and the toothed ring condition

Sensor Cable Shielding Tests
-- Connect ohmmeter as described:

• for RH rear sensor, connect ohmmeter between ECU connector terminals 1 and 4
• for LH rear sensor, connect ohmmeter between ECU connector terminals 1 and 6
• for RH front sensor, connect ohmmeter between ECU connector terminals 1 and 7
• for LH front sensor, connect ohmmeter between ECU connector terminals 1 and 5

-- Correct result should be infinite resistance (open circuit)
-- If value is not correct, inspect cable insulation and repair

Glenn_

iTrader: (1)

can you not just disconnect the abs sensors then use a multimeter to check to see if there working when yet spin the wheels. Is the abs light going off when the car is stood stationery?

PeterRST

iTrader: (1)

That's just what I said.

But it's easier to do it on the multiplug leading to the ABS control box, than having to access the sensor connectors under the rear bench/ in the engine bay individually.

BIL N KEL

Omg Jon cheers for that I'll have look in a bit and let you know how I get on.
Glenn the light Is on all the time

Glenn_

iTrader: (1)

have you checked things like the fuses and relays. My abs light was on the other week from starting the engine up. This was cause of a poor connection. Can you hear the relays clicking after the engine has been started

jon@work

iTrader: (5)

if the light is on all the time, before the car has even moved, then it won't be a wheel sensor

BIL N KEL

Any ideas what it would be? Abs ecu?
It used to work fine then the light started to come on every now and then, eventually it just stayed on

jon@work

iTrader: (5)

unlikely to be the ECU

with the handbrake off, does the red brake warning light go off ?

do you hear the ABS pump working with the ignition switched to position I ?

is the brake fluid level in the reservoir well above the minimum mark ?

BIL N KEL

Yes yes yes
When I push the brake pedal the red brake light flashes on for half second and I can also here a click coming from near glove box Wichita sounds like a relay

jon@work

iTrader: (5)

OK, so perhaps not the usual suspects.........

What exactly is the issue you've got ? So far from this thread, it seems that the orange ABS light comes on immediately when engine started and doesn't go out, and the red brake warning light always comes on after brakes applied. Is this correct ? Any more symptoms ? Do the brakes actually work OK ?

jon@work

iTrader: (5)

Have you checked the brake fluid level with the engine running after the ABS pump has come on and then gone off ?

RickoG66

Actually it could be an abs sensor, the whole system has to be a complete circuit for the light to go off & stay off,

if a sensor is totally shagging & copper windings inside have broken down then that will put the light on

if the sensor is on its way out sometimes when you start the car it does its system check & if everything is ok it will put the light out but when you start driving the sensor that is braking down will start losing its signal & cause a brake in the circuit & bring the light on

also a common 1 i,ve seen a few times it the 2x multiplugs on the resevoir the 3 pin is the brake fluid level warning light that does the light on the dash the 2 pin plug is the brake fluid level warning for the abs ecu, unplug the 2 pin plug & check both electical pins are where they should be as i,ve had one that 1 pin had dropped back into the rubber boot so wasn't making contact as soon as i bridged them it turned the light out & stayed out & abs worked fine

hope some of this helps

jon@work

iTrader: (5)

I wondered if anyone would pick me up on that.

I agree, it could be a sensor fault, but from the problem as described so far then a sensor fault wouldn't be my prime suspect. Of course, if it had been reported that the light had previously come on when the car was being driven and now comes on all the time, I'd agree it's most likely to be a sensor.

BIL N KEL

abs light yes
the red brake light comes on for split second then goes out when the pedal is pressed
the brakes work fine but i have no abs
fluid level is ok

BIL N KEL

if the abs wasn't working would it over pressurise the system? reason is i was told if you pump the pedal on a cossie the red brake light flashes on. i used to get the red light flash on when sitting at traffic lights and keep putting my foot on the brake. i asked on here and was told that all cossies done that

kosman

can i dive in on this...

my car puts the light on as soon as you start it and it never goes out,the red handbrake light never comes on,but myabslight flickered a few times before it stayed on permanent,i have had the resevoir changed though so ill check them plugs because the problem started after this had been changed.

any more ideas what can do it,mega ballache come mot time.

PeterRST

iTrader: (1)

Switch the ABS control unit behind the glove box for another one. My light was on all the time and trying a different one cured it instantly.

BIL N KEL

I have tested the rear sensors and at 25mph there is no voltage reading at all and a very low ohm reading. I also tested the fronts but i don't think I was spinning the wheels fast enough as I got no reading for anything on either

PeterRST

iTrader: (1)

Did you measure in DC or AC?

BIL N KEL

Ac I think

PeterRST

iTrader: (1)

OK, the voltage is very low anyways so make sure you set up your voltmeter correctly.

What was the Ohm reading?

BIL N KEL

About 20-30 at 25 mph

PeterRST

iTrader: (1)

Should be 700 - 1400 Ohm if I remember correctly. Doesn't matter at which speed.

Glenn_

iTrader: (1)

im having problems with mine.Im.wondering if ive got a faulty sensor.Ive got a spare front one and 2 back ones.I will have to try to swap the sensors.