Kelsey Hayes ABS control module 310

[Ken Peter]

Hello group, I have a 1996 K1500 that I just got back on the road after sitting for 12 years. All is doing well but have a ABS light that will not go out.

I have a good scan tool but cannot communicate with the ABS. any ideas. I was thinking a bad 310 control module but cannot find much on how to repair or who could repair.

Thanks for any help.

Ken

 

[spitanddirt]

During the power-on self test, the module checks for input signals from the two front wheel speed sensors and the VSS at the tailshaft of the transfer case. Considering that these particular ABS units aren't prone to any major electronic failures, I would go about checking the resistance readings from both front wheel speed sensors. I bet one is completely out of range. If after driving the truck faster than 3 mph, the ABS light comes on, then I suspect the ABS electrical motor is seized due to carbon from the brushes building up.

I was able to dissect my motor and clean all the carbon out of mine and it worked again.

There is no published procedure for doing this as GM just intended for people to just to replace the ABS as a complete unit. If I recall, the motor can be unbolted and two rivets need drilled out. Then the motor comes apart.

 

[Ken Peter]

I appreciate the write up Spitandirt. Question. My light is always on. Would you expect this with it not communicating. How do wheel sensors send bad feedback when you are not moving?

Thanks again for any help.

 

[spitanddirt]

Pure electrical resistance. If the ABS module doesn't sense a specific resistance reading in any of the sensors, it will illuminate the light.

Sent from my SM-N975U using Tapatalk

 

[Ken Peter]

Pure electrical resistance. If the ABS module doesn't sense a specific resistance reading in any of the sensors, it will illuminate the light.

Sent from my SM-N975U using Tapatalk

Will that cause it to not communicate with scan tool?

Thanks again

 

[df2x4]

Curious which scan tool you're using? I've read that some are picky about ABS and other non-powertrain stuff.

 

[spitanddirt]

FYI: the VSS sensor is supposed to read between 900 and 2000 ohms of resistance. The front wheel speed sensors can have a variable resistance reading depending on temperature. See picture.

So if you are measuring a sensor when the vehicle hasn't been driven, the range is between 2420 and 3450 ohms for a 4WD...on a nice day.

Also, if the ABS light and Brake light both get there signals from the ABS module. So if you can't communicate with the ABS, either your scan tool isn't compatible or there may be some other wiring issues that need to be addressed.

Are you able to read normal OBDII codes? That may help isolate the problem.

Pin 2 and 12 are communication wires for the ABS at the Data Link Connector below the steering column.

You must be registered for see images attach

You must be registered for see images attach

 

[Ken Peter]

Traveling but will try end of the week. Yes I can read normal codes from eccm.

 

[spitanddirt]

Curious which scan tool you're using? I've read that some are picky about ABS and other non-powertrain stuff.

I agree with this comment.

After a bit of exhaustive detective work in my service manuals the other night, the reason that the Tech 2 is capable of scanning all modules(besides being a dealer tool) is that it has two separate communication protocols built into it.

The first protocol is what is called UART. It is very simple form of communication because it is a DIRECT connection to a particular module.

Metaphorically, it's like someone whispering instructions into your ear and that person responding in the same fashion. The key take-away is that this communication is intended for a single recipient and not broadcast to a room full of people.

The second protocol is what GM calls Class 2 Serial Data, otherwise known as SAE J1850-10.4 VPW

This protocol is a form of network communication between modules. In 2008, GM should have switched all vehicles from J1850-10.4 to being CAN compliant.

Controller Area Networks have higher speed buses and greater bandwidth.

In 1996, J1850-10.4 was perfectly suitable because the only modules that needed to communicate with one another were the ECM and the TCM, and sometimes the BCM.

As the modules became more robust and more information sent over the network, it became necessary to link more modules together on the bus.

Again, metaphorically, its like a small group of people talking as group became a room full of people all talking at once.



So, bottom line, scan tools that are capable of both UART and J1850-10.4 protocols cost more because it requires two different types of hardware and their respective software counterparts to talk to these modules.

If you study the Pin-out chart on the picture above, Pin 2 is the only pin that is Class 2 Serial Data. The VCM talks to the ABS on that bus because Pin 2 is connected to both, however, direct communication from a scan tool with the ABS module is only done through Pin 12.

Pin 14 is direct UART communication with the radio, pin 13 is direct UART communication to the Electronic Transfer Case module(if equipped), pin 9 is direct UART communication to the DERM(Airbag module), and pin 8 is direct UART communication to the keyless entry module.

Obviously new cars all link these modules together on the CAN buses so scan tools for new cars only need CAN functionality. The Scan Tool just becomes another module on the network.

Disclaimer: I'm not an electronic engineer, but I do work on aircraft for a living. I'd like to hack my modules just for the fun of it but it's not likely to happen anytime soon.

 

[Erik the Awful]

When I went through school we called it 'multiplexing'. Old school was the computers had separate wires for every signal. When everything went multiplexed, there were processors imbedded in all the electronics, and they could share a single wire to transmit their data digitally.