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ABS Exciter Ring Grooved

12/24/2006


96 SHO with 77,000 miles went to Belle Tire to have the front ball joints
replaced also right front axle because of a tear in the boot. The work order
also listed ABS exciter ring grooved could this be the cause of an
intermittent ABS light ?
Charles Cooper
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Most certainly. You can take the ABS controller connector off. Jack one front wheel off the ground, insert a voltmeter in the appropriate holes, then with the voltmeter on AC start the car, put in first gear and the read the voltage. Then do the other front wheel. They two front wheels should read about the same, in not exactly the same.

Paul

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Thanks for the reply. If the voltage are different how will I know which
one is bad? What is a ABS exciter ring?
Charles
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Most certainly. You can take the ABS controller connector off. Jack one
front wheel off the ground, insert a voltmeter in the appropriate holes,
then with the voltmeter on AC start the car, put in first gear and the
read the voltage. Then do the other front wheel. They two front wheels
should read about the same, in not exactly the same.
Paul
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OK Paul - this is twice TODAY that you have referenced AC voltage on our cars.

I'm Crying Foul. I have NEVER seen AC used on a US made car. Please explain.

To my understanding, the circuit discussed is a simple pulse generator
- i.e. flashes of ON/ Not ON as teeth pass a prox sensor. Why would
they waste time rectifying DC to AC just ffor a pulse signal?

Eric Lehmann
97 Ebony 42k Welded - With the Angels Now so that I don't have to be.
Long Live the Garage Queen !
96 Medium Willow Green Metallic 103k Resurrected, Welded
96 Rosemist 72k 2006 Best Of SHO, Popular Vote, Welded
96 Medium Graphite 120k - Resurrected, Welded
97 Pacific Green - Parting this one Out
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Paul's right. It's A/C voltage. The ring makes the sensor generate an A/C voltage (+ and -). The voltage is positive as the tooth of the ring approaches and then zero and negative as the tooth passes. The ABS module measures the A/C voltage and frequency of the signal to gauge the speed of the wheel. There are a lot of A/C voltage generators. The CPS and CKP sensors are all PM Generators.

Doug Lewis
Ford Performance Specialists Inc.
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Thanks, Sir. Didn't say impossible, just stupid.
I have dozens of pulse generator circuits in many systems that I work
with. DC is used as it is more stable and specific compared to AC,
many folks purposely go through the hassle of changinging AC to DC
just to HAVE DC. Any reason WHY they would use it?

Eric Lehmann
97 Ebony 42k Welded - With the Angels Now so that I don't have to be.
Long Live the Garage Queen !
96 Medium Willow Green Metallic 103k Resurrected, Welded
96 Rosemist 72k 2006 Best Of SHO, Popular Vote, Welded
96 Medium Graphite 120k - Resurrected, Welded
97 Pacific Green - Parting this one Out
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I finally had my ABS controller replaced this week. For over a year it's been saying that the RR sensor is bad then lately the speedometer would periodically go crazy. No ABS light since then.

Richard Wills
99 TR
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Dunno if it has changed from the gen1/2's to the gen3's but in addition to the AC voltage that HAS to be created for the ABS system to work there is also a specified ohm's of resistance range that the sensor needs to be within. I have seen on my own gen2's that the sensor will test out fine for AC but not the ohm's and vice versa. Both times it lead to ABS lights on the dash.

I want to say the ohms is supposed to be around 1050 but I could be mistaken.

Bruce J. Malachuk
03 Redfire Mazda 6s - 17k
94 Opal Frost Taurus SHO -126k
96 Toreador Red Taurus SHO - 68k
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The alternator produces AC voltage which is rectified to DC. Been like that ever since the days of generators. But Ford still calls the alternator a generator in the manual. :)

It is just a voltage created in pulses so it alternates on and off compared to a true DC constant on.

Yes there is a certain resistance the sensors should read.

Item to be Tested Ignition Mode Measure Between Pins Tester Scale/Range Specification Pinpoint Test
Power Feed          
Battery Check OFF Battery Terminals Volts 10 Minimum  
ABS ECU Power ON 14 + 1 Volts 10 Minimum DTC B1318
Pump Motor Power OFF 2 + 1 Volts 10 Minimum DTC C1095
Valve Power OFF 13 + 1 Volts 10 Minimum DTC C1266
Sensor Resistance          
LF Sensor Resistance OFF 15 + 16 KOHMS 1.28-1.92 Kohms A
RF Sensor Resistance OFF 20 + 7 KOHMS 1.28-1.92 Kohms B
LR Sensor Resistance OFF 17 + 18 KOHMS 1.28-1.92 Kohms C
RR Sensor Resistance OFF 4 + 19 KOHMS 1.28-1.92 Kohms D
Sensor Continuity to Ground          
LF to Ground OFF 15 + 1 CONTINUITY No Continuity A
RF to Ground OFF 20 + 1 CONTINUITY No Continuity B
LR to Ground OFF 17 + 1 CONTINUITY No Continuity C
RR to Ground OFF 4 + 1 CONTINUITY No Continuity D
Sensor Output Voltage          
Rotate Wheels at One          
Revolution Per Second          
LF Sensor Output OFF 15 + 16 AC Millivolts greater than 100 mV A
RF Sensor Output OFF 20 + 7 AC Millivolts greater than 100 mV B
LR Sensor Output OFF 17 + 18 AC Millivolts greater than 100 mV C
RR Sensor Output OFF 4 + 19 AC Millivolts greater than 100 mV D
ABS Warning Lamp Check ON 22 +1 Volts 10 V min E
Stoplamp Switch Check          
Brake Pedal Applied OFF 9 + 1 Volts 10 Minimum  
Brake Pedal Released OFF 9 + 1 Volts 0.5 Maximum  


Paul N
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This is why my car would not start. Paul sent me the write-up that explained the theory of operation. I originally thought the Crank Position Sensor was a simple "On/Off switch and therefore would not be polarized. Oddly enough the replacement pigtail was not marked and as luck would have it, I chose the wrong way to spliced them.
Carter Fuji
Latitude 35.23948924537855, Longitude -94.30673988764765
'97 ES Whoosh CarDomain Site
Supercharger Video Link 
Greenwood, AR.
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Why would they do it? Money.

PM generators are cheap. It's a solid iron core with a coil of wire wrapped around it.

It follows the basic principle: "If you have to ask yourself why the company did something and the answer isn't blatantly obvious, the answer is money."

Somehow, they saved money by doing it this was.


Bruce, the V-6 cars had what's called Low Data Rate Electronic Ignition. Engine rotation information was monitored by Hall Effect switches. A Hall Effect switch uses a transistor that's controlled by a magnet. The device that it's monitoring has a windowed reluctor. When the window is open, the magnetic field of the magnet biases the transistor and there is a positive voltage output (12v). When the reluctor window closes, the magnetic field blocked and the transistor turns off and the voltage drops to zero. The output of this type of sensor outputs a square wave, zero to 12v.

Doug Lewis
Ford Performance Specialists Inc.


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