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
____________________________________________________________________________
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
___________________________________________________________________________
Thanks for the reply. If the voltage are different how will I know which
one is bad? What is a ABS exciter ring?
Charles
___________________________________________________________________________
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
___________________________________________________________________________
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
___________________________________________________________________________
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.
___________________________________________________________________________
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
___________________________________________________________________________
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
___________________________________________________________________________
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
___________________________________________________________________________
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
___________________________________________________________________________
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.
___________________________________________________________________________
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.
