Chevrolet C&K Pickup (Pre-1999):

Intermittent ABS light on no code

You are not logged in.

# 1  8/19/2012 12:57 PM

captain83
New member
Registered: 8/9/2009
Posts: 4

Intermittent ABS light on no code

I have a 1997 K 1500, 5.7 L, 4x4, after driving a short distance my ABS light comes on, if I turn off the engine and restart it light goes out, but comes on shortly after. I have an Actron scanner with ABS code reader, but no codes appear. I even plugged in my scanner while the engine was still running with ABS light still on and still no codes. I disconnected both front wheel sensors, hook up AC volt meter an spun the wheel by hand. I am getting more than the required 350 millivolts, so I'm assuming the wheel sensor is not the problem. Please help thank you.

Offline

 

# 2  8/19/2012 2:47 PM

TechHelp2
Administrator
Registered: 11/24/2009
Posts: 1299

Re: Intermittent ABS light on no code

Upon investigation, you probably will not find any DTC's (Data Trouble Codes).

The cause of this condition may be an increased air gap between the wheel speed sensor and the hub reluctor ring due to rust and debris built up on the sensor mounting surface.

Correction

Measure AC voltage and clean wheel speed sensor mounting surfaces.

1. Raise the vehicle on a hoist.

2. Disconnect both the front wheel speed sensor harness connectors.

3. Place a DVM across the terminals of each sensor connector.

4. Rotate the wheel with hand speed and measure the AC MVs. The reading should be at least 350 AC MVs.

5. If the reading is between 200 and 350 AC MVs, remove the wheel, caliper and rotor in order to gain access to the speed sensor.

6. Remove the wheel speed sensor and plug the hole to prevent debris from falling into the hub during service.

7. Clean the wheel speed sensor mounting surface using a wire brush, sand paper, emery cloth, Scotch Brite (TM) or other suitable material. Be sure to thoroughly clean the wheel speed sensor surface. There should be no rust or corrosion.

8. Check the sensor head to determine if it has been warped/distorted due to the corrosion build up or other causes. Check the mounting surface on the sensor head for flatness by placing it on the edge of a metal machinists scale or other suitable straight edge to measure the flatness. Check the sensor for flatness in multiple (minimum 3) positions/directions. If the sensor head is distorted, replace the sensor.

9. Apply (spray) two thin coats of the specified rust penetrating lubricant (corrosion inhibitor) to the complete sensor mounting surface on the bearing hub. Allow to dry for 3-5 minutes between coats. Use ONLY Rust Penetrating Lubricant, P/N 89022217 (Canadian P/N 89022218).

10. When the corrosion inhibitor is dry to the touch (about 10 minutes), apply a thin layer of bearing grease to the hub surface and sensor 0-ring prior to sensor installation. Use ONLY Wheel Bearing Lubricant, P/N 01051344 (Canadian P/N 993037).

11. Install either the original sensor or a new one in the hub and secure the sensor. Ensure that the sensor is seated flush against the hub.

12. Install the rotor, the caliper and the wheel.

13. Place the DVM across the sensor terminals and recheck the voltage while rotating the wheel by hand. The voltage should now read at least 350 AC MVs.

Parts of this information was supplied by the Alldata information website.


realworldautomotive.com
car and truck information like nowhere else

Offline

 

# 3  8/19/2012 3:18 PM

captain83
New member
Registered: 8/9/2009
Posts: 4

Re: Intermittent ABS light on no code

Sorry but I just explained I already checked the voltage on both wheel sensors and they were 350 millivolts or greater. So now I'm assuming the air gap must be OK and it does not need cleaning. Where do I go from here? Or am I mistaken and whether or not I have the correct voltage at the sensors, I might still need to clean them.


TechHelp2 wrote:

Upon investigation, you probably will not find any DTCs (Data Trouble Codes).

The cause of this condition may be an increased air gap between the wheel speed sensor and the hub reluctor ring due to rust and debris built up on the sensor mounting surface.

Correction

Measure AC voltage and clean wheel speed sensor mounting surfaces.

1. Raise the vehicle on a hoist.

2. Disconnect both the front wheel speed sensor harness connectors.

3. Place a DVM across the terminals of each sensor connector.

4. Rotate the wheel with hand speed and measure the AC mV's. The reading should be at least 350 AC mV's.

5. If the reading is between 200 and 350 AC mV's, remove the wheel, caliper and rotor in order to gain access to the speed sensor.

6. Remove the wheel speed sensor and plug the hole to prevent debris from falling into the hub during service.

7. Clean the wheel speed sensor mounting surface using a wire brush, sand paper, emery cloth, Scotch Brite(TM) or other suitable material. Be sure to thoroughly clean the wheel speed sensor surface. There should be no rust or corrosion.

8. Check the sensor head to determine if it has been warped/distorted due to the corrosion build up or other causes. Check the mounting surface on the sensor head for flatness by placing it on the edge of a metal machinists scale or other suitable straight edge to measure the flatness. Check the sensor for flatness in multiple (minimum 3) positions/directions. If the sensor head is distorted, replace the sensor.

9. Apply (spray) two thin coats of the specified rust penetrating lubricant (corrosion inhibitor) to the complete sensor mounting surface on the bearing hub. Allow to dry for 3-5 minutes between coats. Use ONLY Rust Penetrating Lubricant, P/N 89022217 (Canadian P/N 89022218).

10. When the corrosion inhibitor is dry to the touch (about 10 minutes), apply a thin layer of bearing grease to the hub surface and sensor 0-ring prior to sensor installation. Use ONLY Wheel Bearing Lubricant, P/N 01051344 (Canadian P/N 993037).

11. Install either the original sensor or a new one in the hub and secure the sensor. Ensure that the sensor is seated flush against the hub.

12. Install the rotor, the caliper and the wheel.

13. Place the DVM across the sensor terminals and recheck the voltage while rotating the wheel by hand. The voltage should now read at least 350 AC mV's.

Parts of this information was supplied by the Alldata information website.

Offline

 

# 4  8/19/2012 10:52 PM

TechHelp2
Administrator
Registered: 11/24/2009
Posts: 1299

Re: Intermittent ABS light on no code

The chart I have listed below is not for your problem but it does have the resistance chart needed to check the wheel sensors for resistance.

Recheck the system with a good professional scanner to see what code comes up. Your scanner may not be updated to the year of your truck.

See if you can clear the codes (if any) and see if the light comes back on. Just because you restart the truck doesn't mean the code is erased.

Try the suggestions I gave you and get back to me with the results.


https://www.realworldautomotive.com/forums/uploads/thumbs/174_57434424.gif


realworldautomotive.com
car and truck information like nowhere else

Offline

 

# 5  8/20/2012 9:47 PM

captain83
New member
Registered: 8/9/2009
Posts: 4

Re: Intermittent ABS light on no code

TechHelp2 wrote:

The chart I have listed below is not for your problem but it does have the resistance chart needed to check the wheel sensors for resistance.

Recheck the system with a good professional scanner to see what code comes up. Your scanner may not be updated to the year of your truck.

See if you can clear the codes (if any) and see if the light comes back on. Just because you restart the truck doesn't mean the code is erased.

Try the suggestions I gave you and get back to me with the results.


https://www.realworldautomotive.com/for…434424.gif

I appreciate your help. I just want to state again, by turning the key off & back on the light goes out for a bit, but again whether the light is on or off there are no codes stored. Now I have a Actron CP9580 scanner, which is suppose to read both engine & ABS codes. I know it's not the best scanner, but that's all I have (maybe my scanner isn't picking up the codes, I don't know) but it's suppose to. I'm trying to avoid going to a dealer & paying for it to be read.
Now as far as checking resistance, can't I just use the ohms scale on my multi-meter just like I used it for the AC millivolt test?

I will perform the test you sent on DTC C0022, but it's telling me to use a J39200 to measure resistance, what is this tool & how expensive is it to purchase? I probably won't get to this test till the weekend, I'm an old man with back problems, but I will get back to you after the test, but please respond on this J39200 tool & if I can perform the test without it. I'm kinda new on this site so bear with me.

Offline

 

# 6  8/21/2012 5:24 AM

TechHelp2
Administrator
Registered: 11/24/2009
Posts: 1299

Re: Intermittent ABS light on no code

I'm sorry I didn't say you had a code 22, I just used the article because I couldn't separate the two.

The J39200 is just a digital volt/ohm meter. If you have a volt/ohm meter that also checks resistance then that is good.

To check if your scanner is correct; take your truck to a auto part store like Auto Zone and have them scan the computer. If there scanner comes up with no codes like yours then you have a positive answer that your scanner is ok. They should do it for free, check to make sure.

When you turn the truck on an intermittent code will not illuminate the light until it sees the problem again. When you turn the truck off and turn the ignition back on and drive the light will stay off until the problem comes up again.

Check connectors for loose wires, corrosion or wires being broken. Some intermittent problems are caused by broken wires and depending on the wheel position is when the code is set and puts the light on.

The tone wheels are attached to the rotor on 2WD models and are integral with the wheel bearing on 4WD models. Any imperfections in the tone wheels, such as a broken or missing tooth, can cause an inaccurate wheel speed reading on the affected wheel. You may not be able to see the tone wheel if it is on the bearing, you may have to remove the sensor to check it out.

Get back to me when you can.


realworldautomotive.com
car and truck information like nowhere else

Offline

 

# 7  8/22/2012 11:21 PM

captain83
New member
Registered: 8/9/2009
Posts: 4

Re: Intermittent ABS light on no code

TechHelp2 wrote:

I'm sorry I didn't say you had a code 22, I just used the article because I couldn't separate the two.

The j39200 is just a digital volt/ohm meter. If you have a volt/ohm meter that also checks resistance then that is good.

To check if your scanner is correct; take your truck to a auto part store like Auto Zone and have them scan the computer. If there scanner comes up with no codes like yours then you have a positive answer that your scanner is ok. They should do it for free, check to make sure.

When you turn the truck on an intermittent code will not illuminate the light until it sees the problem again. When you turn the truck off and turn the ignition back on and drive the light will stay off until the problem comes up again.

Check connectors for loose wires, corrosion or wires being broken. Some intermittent problems are caused by broken wires and depending on the wheel position is when the code is set and puts the light on.

The tone wheels are attached to the rotor on 2WD models and are integral with the wheel bearing on 4WD models. Any imperfections in the tone wheels, such as a broken or missing tooth, can cause an inaccurate wheel speed reading on the affected wheel. You may not be able to see the tone wheel if it is on the bearing, you may have to remove the sensor to check it out.

Get back to me when you can.

Thanks TechHelp2,
                             Like I said I won't be able to get to it till the weekend, but I will do what you suggested and get back to you. You've been very helpful. Thanks again.

Offline

 
E-mail Page
Print Page
Save or Share Information
ALLDATAdiy.com is the leading source of factory diagnostic & repair information specific to your car.

Powered by PunBB
Copyright © 2007-  RealWorldAutomotive.com

Save or Share Automotive Information
Custom Search