wheel speed sensors
#1
10-28-2016 | 01:18 PM
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From: upstate NY USA
wheel speed sensors
I have a check engine light, and the ABS light on. The codes are C 1155, and C 1165 the right rear and left front wheel speed sensors circuit failure. I went through the required test procedure, and everything points to the sensors being bad. I'd like to know if there is a way to test the sensors before springing for replacements, and also if this is a normal problem.
Thanks, Butch
Thanks, Butch
#2
10-28-2016 | 05:05 PM
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Joined: May 2008
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From: Great Mills, MD
Butch, having the speed sensors fail is not unlikely. Granted, before you replace the sensors, do a good look at the wiring between the body and the sensors. This wiring is known to get damaged and can result in loss of signal to the ABS module, which is what receives the 4 wheel speed signals.
As for testing the wheel speed sensors. What you need to do is to remove the sensor from the vehicle. You will see that there are 2 pins on the sensor. You will want to connect a multimeter to these two pins (where the red and black leads are doesn't matter). The big thing is you want a multimeter that is either an analog model or a digital one with the bar on the screen that gives out an instantaneous reading. You will want to rest the sensor near the edge of a table or other stable item. Next, using a large metallic item (steel bar, large screw driver, etc), pass this near the end of the sensor. The faster and closer to the sensor you can get, the larger the pulse will be, but make sure NOT!!!!! to hit the sensor. So, start out slow and work your way up as you get a feel for things. What you are looking for is the with the multimeter set on the 2VDC scale, the meter should peg out as the metal object passes by and will quickly return to 0 VDC. If you see very little/no reaction, then your sensor is toast. If you are seeing a good pulse on the multimeter, then you need to be looking at the wiring.
If you need more help, let me know.
As for testing the wheel speed sensors. What you need to do is to remove the sensor from the vehicle. You will see that there are 2 pins on the sensor. You will want to connect a multimeter to these two pins (where the red and black leads are doesn't matter). The big thing is you want a multimeter that is either an analog model or a digital one with the bar on the screen that gives out an instantaneous reading. You will want to rest the sensor near the edge of a table or other stable item. Next, using a large metallic item (steel bar, large screw driver, etc), pass this near the end of the sensor. The faster and closer to the sensor you can get, the larger the pulse will be, but make sure NOT!!!!! to hit the sensor. So, start out slow and work your way up as you get a feel for things. What you are looking for is the with the multimeter set on the 2VDC scale, the meter should peg out as the metal object passes by and will quickly return to 0 VDC. If you see very little/no reaction, then your sensor is toast. If you are seeing a good pulse on the multimeter, then you need to be looking at the wiring.
If you need more help, let me know.
#4
10-29-2016 | 05:38 AM
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Posts: 14,475
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From: Great Mills, MD
Jagger, do you have a battery powered O'scope? If yes, then you can. Otherwise, trying to do this in a moving car may prove to be very troublesome. With the o-scope, you can compare not only the amplitude, but the frequency. The computer needs a certain voltage (amplitude) to say that it is a good pulse to count. The frequency is what it uses to say how fast you are going (the more pulses over a given time, the faster it will say you are going). If you have a weak sensor, it may be right at the threshold of having a good enough amplitude and the ABS module is only counting a few of the pulses. This would throw the car into a tizzy as it sees the wheels spinning at different rates and would cause the ABS system to think the wheels are locking up. Granted, with the codes, it would appear that you are getting no pulses.
Of note, you may want to remove the rear wheel speed sensor and look down in the hole. You should see a metal band with rectangular slots cut out of it. It is a common issue that this band will break, leading to a C1165 code. This would require the replacement of the rear CV axle. This is where checking the sensor with the multimeter and metal stick will tell you the sensor is just fine. the front one, the other half of the sensor is in the wheel bearing and if you lost that, you have much bigger problems.
Of note, you may want to remove the rear wheel speed sensor and look down in the hole. You should see a metal band with rectangular slots cut out of it. It is a common issue that this band will break, leading to a C1165 code. This would require the replacement of the rear CV axle. This is where checking the sensor with the multimeter and metal stick will tell you the sensor is just fine. the front one, the other half of the sensor is in the wheel bearing and if you lost that, you have much bigger problems.