What is the ABS supply voltage to RWAL sensor on 99 Ram 1500 ?
#1
08-14-2018, 07:49 PM
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What is the ABS supply voltage to RWAL sensor on 99 Ram 1500 ?
Is the correct ABS voltage supply to the RWAL sensor on 99 Ram 5v or 12v ?
I'm getting 5v. If it should be 12v then I may have possible short or bad ABS control module.
If It should be 5v then I most likely have a bad sensor.
The wiring between the module and sensor checked out; also the sensor's ohm reading was around 1800.
I did the spin wheel test and got 0 volts; so I'm thinking either a bad sensor or bad module.
Any info on the correct voltage supply will be helpful.
I'm getting 5v. If it should be 12v then I may have possible short or bad ABS control module.
If It should be 5v then I most likely have a bad sensor.
The wiring between the module and sensor checked out; also the sensor's ohm reading was around 1800.
I did the spin wheel test and got 0 volts; so I'm thinking either a bad sensor or bad module.
Any info on the correct voltage supply will be helpful.
#2
08-14-2018, 10:56 PM
iirc, the wheel speed sensors should not have voltage supplied to them. they are passive sensors. they generate ac voltage when the wheel is turning...zero volts when stopped. the only part that should be supplied power is the abs module and pump. unplug another wheel speed sensor and check it...if its zero volts, you may have a short to power on the other circuit.
4th gen trucks use active abs sensors that are sent voltage.
if the abs light is on...there is a stored ab code present. have it read with a scan tool that can access chassis codes. post the code here.
4th gen trucks use active abs sensors that are sent voltage.
if the abs light is on...there is a stored ab code present. have it read with a scan tool that can access chassis codes. post the code here.
Last edited by primem; 08-14-2018 at 10:59 PM.
#3
08-16-2018, 12:00 AM
iirc, the wheel speed sensors should not have voltage supplied to them. they are passive sensors. they generate ac voltage when the wheel is turning...zero volts when stopped. the only part that should be supplied power is the abs module and pump. unplug another wheel speed sensor and check it...if its zero volts, you may have a short to power on the other circuit.
4th gen trucks use active abs sensors that are sent voltage.
if the abs light is on...there is a stored ab code present. have it read with a scan tool that can access chassis codes. post the code here.
4th gen trucks use active abs sensors that are sent voltage.
if the abs light is on...there is a stored ab code present. have it read with a scan tool that can access chassis codes. post the code here.
#4
08-16-2018, 11:19 AM
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iirc, the wheel speed sensors should not have voltage supplied to them. they are passive sensors. they generate ac voltage when the wheel is turning...zero volts when stopped. the only part that should be supplied power is the abs module and pump. unplug another wheel speed sensor and check it...if its zero volts, you may have a short to power on the other circuit.
4th gen trucks use active abs sensors that are sent voltage.
if the abs light is on...there is a stored ab code present. have it read with a scan tool that can access chassis codes. post the code here.
4th gen trucks use active abs sensors that are sent voltage.
if the abs light is on...there is a stored ab code present. have it read with a scan tool that can access chassis codes. post the code here.
ACTIVE WSS SENSORS
In recent years, several new types of “active” WSS sensors have appeared. These are used on many 1999 and newer Chrysler, Jeep and Mercedes models with Teves Mark 20e and up Teves ABS systems. Active WSS sensors are also found on the Ford Focus, Toyota Tundra and other applications. This type of sensor is becoming more common on late-model vehicles because of its greater accuracy at low speeds. Active WSS sensors, which Chrysler refers to as “magneto-resistive” sensors, work like a “Hall effect” sensor and generate a square wave on-off digital signal that changes frequency with wheel speed. This type of sensor detects the change in magnetic polarity (flux) as the teeth on the tone ring or small magnets pass under it. Small magnets may be built into the wheel bearings or bearing seal for the WSS sensor to read. Active sensors often have three wires: a voltage reference input (5 to 12 volts), a signal output and ground. But some active sensors have only two wires (reference voltage and signal return). How can you tell a 2-wire active sensor from a 2-wire passive sensor? Turn the ignition on and backprobe both wires with a voltmeter. If you see a voltage reading (5 to 12v), you have an active WSS sensor. If you see no voltage (0v), you have a passive WSS sensor. Active WSS sensors also have an integrated circuit within the sensor itself that converts and amplifies the signal before it goes back to the control module. This allows the sensor to read wheel speeds all the way down to zero mph (which improves ABS control at low speeds as the vehicle comes to a halt). When the key is on, an active WSS sensor has two states: low and high. In the low state, it generates a fixed 0.9 volt return signal of about 7 milliamps. In the high state, it generates a signal of 1.65 volts and 14 milliamps. The rate at which it toggles back and forth between its high and low states corresponds to the speed of the wheel. This type of sensor must be connected to its wiring harness to test it, and the ignition key must be on so the control module can provide reference voltage to the sensor. If you forget and leave the key off, you won’t get any output from an active WSS sensor. Because of the added electronic circuitry inside the sensor, and active WSS sensor cannot be tested with an ohmmeter like a passive WSS sensor. You have to look at its output signal when the wheel is turning and the ignition is on. This can be done with a scan tool (look for a mph reading while spinning the tire or during a test drive), with a voltmeter (turn the wheel very slowly and look for a change in the voltage output from high to low), with a NOID light (the LEDs on the NOID light will flash when it detects a signal pulse), or a DSO. The waveform on the scope should show a square wave pattern that changes from low (0.9v) to high (1.65v) as the wheel turns. The difference in height of the waveform should be 0.75 volts (1.65v minus 0.9v).
#5
08-16-2018, 11:56 AM
I have no code showing on scan tool. Trying to verify whether I have a passive or active sensor before replacing CAB; this what I came up with:
ACTIVE WSS SENSORS
In recent years, several new types of “active” WSS sensors have appeared. These are used on many 1999 and newer Chrysler, Jeep and Mercedes models with Teves Mark 20e and up Teves ABS systems. Active WSS sensors are also found on the Ford Focus, Toyota Tundra and other applications. This type of sensor is becoming more common on late-model vehicles because of its greater accuracy at low speeds. Active WSS sensors, which Chrysler refers to as “magneto-resistive” sensors, work like a “Hall effect” sensor and generate a square wave on-off digital signal that changes frequency with wheel speed. This type of sensor detects the change in magnetic polarity (flux) as the teeth on the tone ring or small magnets pass under it. Small magnets may be built into the wheel bearings or bearing seal for the WSS sensor to read. Active sensors often have three wires: a voltage reference input (5 to 12 volts), a signal output and ground. But some active sensors have only two wires (reference voltage and signal return). How can you tell a 2-wire active sensor from a 2-wire passive sensor? Turn the ignition on and backprobe both wires with a voltmeter. If you see a voltage reading (5 to 12v), you have an active WSS sensor. If you see no voltage (0v), you have a passive WSS sensor. Active WSS sensors also have an integrated circuit within the sensor itself that converts and amplifies the signal before it goes back to the control module. This allows the sensor to read wheel speeds all the way down to zero mph (which improves ABS control at low speeds as the vehicle comes to a halt). When the key is on, an active WSS sensor has two states: low and high. In the low state, it generates a fixed 0.9 volt return signal of about 7 milliamps. In the high state, it generates a signal of 1.65 volts and 14 milliamps. The rate at which it toggles back and forth between its high and low states corresponds to the speed of the wheel. This type of sensor must be connected to its wiring harness to test it, and the ignition key must be on so the control module can provide reference voltage to the sensor. If you forget and leave the key off, you won’t get any output from an active WSS sensor. Because of the added electronic circuitry inside the sensor, and active WSS sensor cannot be tested with an ohmmeter like a passive WSS sensor. You have to look at its output signal when the wheel is turning and the ignition is on. This can be done with a scan tool (look for a mph reading while spinning the tire or during a test drive), with a voltmeter (turn the wheel very slowly and look for a change in the voltage output from high to low), with a NOID light (the LEDs on the NOID light will flash when it detects a signal pulse), or a DSO. The waveform on the scope should show a square wave pattern that changes from low (0.9v) to high (1.65v) as the wheel turns. The difference in height of the waveform should be 0.75 volts (1.65v minus 0.9v).
ACTIVE WSS SENSORS
In recent years, several new types of “active” WSS sensors have appeared. These are used on many 1999 and newer Chrysler, Jeep and Mercedes models with Teves Mark 20e and up Teves ABS systems. Active WSS sensors are also found on the Ford Focus, Toyota Tundra and other applications. This type of sensor is becoming more common on late-model vehicles because of its greater accuracy at low speeds. Active WSS sensors, which Chrysler refers to as “magneto-resistive” sensors, work like a “Hall effect” sensor and generate a square wave on-off digital signal that changes frequency with wheel speed. This type of sensor detects the change in magnetic polarity (flux) as the teeth on the tone ring or small magnets pass under it. Small magnets may be built into the wheel bearings or bearing seal for the WSS sensor to read. Active sensors often have three wires: a voltage reference input (5 to 12 volts), a signal output and ground. But some active sensors have only two wires (reference voltage and signal return). How can you tell a 2-wire active sensor from a 2-wire passive sensor? Turn the ignition on and backprobe both wires with a voltmeter. If you see a voltage reading (5 to 12v), you have an active WSS sensor. If you see no voltage (0v), you have a passive WSS sensor. Active WSS sensors also have an integrated circuit within the sensor itself that converts and amplifies the signal before it goes back to the control module. This allows the sensor to read wheel speeds all the way down to zero mph (which improves ABS control at low speeds as the vehicle comes to a halt). When the key is on, an active WSS sensor has two states: low and high. In the low state, it generates a fixed 0.9 volt return signal of about 7 milliamps. In the high state, it generates a signal of 1.65 volts and 14 milliamps. The rate at which it toggles back and forth between its high and low states corresponds to the speed of the wheel. This type of sensor must be connected to its wiring harness to test it, and the ignition key must be on so the control module can provide reference voltage to the sensor. If you forget and leave the key off, you won’t get any output from an active WSS sensor. Because of the added electronic circuitry inside the sensor, and active WSS sensor cannot be tested with an ohmmeter like a passive WSS sensor. You have to look at its output signal when the wheel is turning and the ignition is on. This can be done with a scan tool (look for a mph reading while spinning the tire or during a test drive), with a voltmeter (turn the wheel very slowly and look for a change in the voltage output from high to low), with a NOID light (the LEDs on the NOID light will flash when it detects a signal pulse), or a DSO. The waveform on the scope should show a square wave pattern that changes from low (0.9v) to high (1.65v) as the wheel turns. The difference in height of the waveform should be 0.75 volts (1.65v minus 0.9v).
#6
08-16-2018, 12:35 PM
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#7
08-16-2018, 01:39 PM
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I think the priority here is to find out weather I have a passive or active sensor so I can determine if I have a bad sensor or a short to voltage in the control module (CAB).
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#8
08-16-2018, 02:17 PM
Checked the service manual and it shows #13 blank; so I checked 13 on the OBD2 connector and it is blank.
I think the priority here is to find out weather I have a passive or active sensor so I can determine if I have a bad sensor or a short to voltage in the control module (CAB).
I think the priority here is to find out weather I have a passive or active sensor so I can determine if I have a bad sensor or a short to voltage in the control module (CAB).
#9
08-16-2018, 02:20 PM
