Yes, but I'm not sure what the resistance value should be, just compare all 4.

 

1000 to 1500 ohms when you have the wheel rotating by hand.

a wheel speed sensor is out of the acceptable resistance range, the ABS warning should turn on and remain on when the ignition is turned on. If the warning lamp cycles on then back off after a few seconds, that usually means the wheel senor circuits are within the acceptable resistance range. This power-on test is intended to check for speed continuity and shorts.

If all the wheel speed sensor circuits pass the resistance test, you can test the output of each sensor. Connect your AC voltmeter to the sensor leads. Spin the hub or wheel at about 1 revolution per second (approximately 5 MPH). Read the AC voltage produced by each sensor. Rear sensors should produce a minimum of about 0.6VAC, front sensors should produce a minimum of about 0.9VAC. Lack of adequate signal from a sensor will set a code as soon as the vehicle is moving about 5-7 MPH. The EBCM actually reads the frequency of the sensor signals, but the AC output voltage is a good indication of sensor performance.

Each wheel sensor harness should also have a DC bias voltage when the ignition is on. The wheel speed sensor connector (vehicle harness end) should have between 2.5-5VDC at each wheel. Lack of a bias voltage can indicate a wire harness or EBCM problem.

The EBCM also relies on a VSS signal from the PCM. If the wheel sensors check out as normal, and the ABS warning lights at about 5-7 MPH, that can indicate the lack of a VSS signal (the EBCM is receiving all wheel signals but no vehicle speed signal).

Other things to check are the brake fluid level sensors, brake pedal switches, and the rear/center brake lamp. Some systems use the brake pedal switch and filament of the center brake lamp as redundant inputs, and a failed center brake lamp can cause the ABS warning to light (as well as cause the cruise control to be inoperative).

 

Thanks for the info 463.

I'll have to check everything out this weekend if I get some time. I checked the ohms on the wheel sensors a while back, but didn't have any info on how to do it. If I remember right one of the sensors showed as open and didn't register anything on the DVM.

Bob

 

Concerning the power on test mentioned above, my abs and traction off lights come on and go off as described, but they return, along with the service traction system light, when I start the car. I have checked one hub with an ohmmeter, and it reads open, but I wasn't turning the wheel. Was this check valid ? Any thoughts on the lights behavior ?

I have been fighting this for some time. The hub I checked had been installed only a week before...

Any thoughts are greatly appreciated.

B
2002 Impala LS
3.8 L V6

 

Concerning the power on test mentioned above, my abs and traction off lights come on and go off as described, but they return, along with the service traction system light, when I start the car. I have checked one hub with an ohmmeter, and it reads open, but I wasn't turning the wheel. Was this check valid ? Any thoughts on the lights behavior ?

I have been fighting this for some time. The hub I checked had been installed only a week before...

Any thoughts are greatly appreciated.

B
2002 Impala LS
3.8 L V6

I would rotate the wheel testing for a reading first.
Next is to look for power at the conector plug unpluged at the hub. Then with the key in the on pos look for 5 vdc on the feed line to the hub. What i have had to do is pull the wire harness right out and bench test each of the two wires with the meter and flex all the way down the wire till i get a open or number movement on the meter then repair the brake in the wire. Note that this wire is a very fine multy strand wire and with a 1/3 of the wires broke in the wire it is enough to cause a fault light with abs /trac systems.
If there is not a cash problem they can be replaced.
keep me posted and we will help you get it fixed.k3:

 

All correct information given by user "463". Another addition: 00-05 impala's have faulty or incorrectly designed abs harness's. Mainly the front one's though. GM wrapped the wires in electrical tape inside of the cable looming. In combination with that they made the front harness's too short which causes binding and eventually cracking the wires inside. Check the voltage and resistance as stated above. If nothing is found faulty, call your local advance auto store's. Some of them have ABS capable OBD scanners and will be able to pinpoint the correct wheel.

Important: Before plugging the connectors back onto the hubs, apply dielectric grease to each hub pin or connector!! These connectors are very prone to moisture in the rain/winter and can cause problems. Dielectric grease is a savior. I can't say this enough

 

Thank you Gentlemen ! I'm gonna hit this in the morning. I'll report back with the results.

 

Before you change the rear hubs lets do a bit more testing. I can't tell you what the #s are for the rear hubs are.
9 out of 10 times there is a partial wire or broken wire on one or both or the front hubs.
Try one more thing turn on the key and unplug the right conector use a tester on VDC and see if you have 5 VDC + or - .2 volts at the car plug and do the left side and see if you get 5 VDC + or - .2 volts.
make sure to bend and tug on the wires and retest as well as during the test.

 

Right front, 5.02 VDC. Left front 5.02 VDC. I slowly moved the connector around, as you recommend. The jumper harness for the right front has been replaced. Shall I replace the left front jumper harness ($27) before investing in the rear hubs ? Seems logical...

 

If your reading 5 volts it should be good.
now at the rear hubs you could un plug the conector and see if you have 5 volts.
It seams weird that both would fail.

 

That's what I was thinking. Both rears showing 5.02VDC. I'm going to change the left front jumper harness. It is stiff and doesn't want to flex a few inches from the hub. I'll report back what I find.

 

Good idea. If the front one has not been replaced already chances are its in bad shape anyways. I would peel the cable looming off of the rear connectors and inspect the wires. Or at a bare minimum remove the rear harness from the trac bar and test voltage with key on while you wiggle and twist the cable. Just b/c its showing the correct voltage doesn't mean their isn't a break in the wire's.

 

^^ Take it to a GM dealer and have them diagnose the problem. Have them hook it up to their tech 2 scanner and take it for a ride. They will be able to monitor all abs sensors as well as the BCM (brake control module). There are too many possibilities it could be including: Ignition switch, BCM, abs pump, wheel hubs, etc. I just hope it's not your BCM like mine was ($900 part).

Is there any sloppyness in the ignition? Have you ever had a passlock security problem?

 

Instead of paying Chevy (another) $113, I spent $65 on an ABS code scanner. The new left front harness has been installed. The scanner reported 8 codes when I plugged it in. I wrote them down, cleared the codes, and went for a ride around the block. Checked codes again when I got home, just one. C1218. The brake pump wiring is faulty. Time to put that new test meter to work.

Thank you to all who helped me with this deal. Your insight and suggestions are greatly appreciated !

B

 

BCM should have cost half that, including programming, installation, and brand new GM part.

 

Sorry I should have been more clear. My complete assembly (BCM, ABS pump, valve's) where replaced.

 

I found this on another forum.
Just FYI


You can test the speed sensors yourself.

Front sensor specs:
956 to 1240 ohms in 41 to 110 degree weather
at least 100mV AC (NOT DC!) volts when hub is spun by hand
Rear sensor specs:
950 to 1300 ohms in 41 to 110 degree weather
At least 100mV AC (NOT DC!) volts when hub is spun by hand

 

so we wait till a code show up. :yahoo:

 

Already fixed this, it was the sensor in the hub. Just used an DVM to check it. Replaced it about two months ago.

Bob

 

Does anyone have a wiring diagram of the wheel sensor harness? I replaced both front wheel sensor harnesses because I could wiggle the main harness that they go into and temporary fix indicator lights. My guess is that it is further up the harness from where I spliced in the wheel sensors.

Thanks
Russ

 

How can u tell it's the harness yet? Have you tested the output voltage? Or u just assuming b/c the lights are back on?

The main section that usually ever gets damaged is about a 16" long section from the sensor on up. The wires usually fail at the point of the hold-down on the control arms.

 

The harness that you buy has like 3 feet of wire, if you spliced as far in as you can get, it shouldn't be an issue. What good would a diagram be?

 

I would like to jumper the wheel sensor harness (which I replaced) to the junction point/connector. A wiring diagram would usually show the routing of the wires. I would be happy with which connector the wheel sensor wires go into.

 

2010 Impala LT that lives in the Rustbelt. Intermittent Stabilitrak warnings. Dealer found bad harness LF. A wire corrroded away from one of the two male pins in the connector housing. Turned out to be a ~$400 fix for splicing in a new harness.

 

Hate to bring up a old post but I'm having a issue with the rr wiring, scanner shows no speed from that wheel, I measured voltage but didn't know what I was lookikkg for, now i do, it has 14mv so prob nothing , does anyone know where these wires run when they get up front, I'd rather just replace as much as I can in one shot.

 

I have a 2017 silverado 1500 v8 l83, on my scan tool it shows 107 km/h or 66 mph on both rear wheels I disconnected the sensor and my scan tool still shows 107 could it be 5he ebcm?