M923A1 Abs Light

[jonesal]

Positive. See Motherlode of TM's thread where we talk about the 23 series TMs. PM your email address and I will send it to you.

The site boss'es have 'em, they just haven't put them up yet.

Al Jones
'84 M923

 

[FASTNOVA]

TM 9-2320-272-23-2 should get you where you need to go. I has both methods for troubleshooting: with and without the Haldex Info Centre (spelled correctly). It's tedious but follow the procedure. I did and found my problem was a shorted wire. Troubleshooting took two hours and the fix took 2 minutes.

Good luck.

Al Jones
'84 M923

Can you please let us know where you found the short, it would save other members a lot of trouble shooting time.

 

[juanprado]

23 series for M939

Fastnova:

check out this thread:
http://www.steelsoldiers.com/5-ton-up/93023-mother-load-tms.html

 

[jonesal]

My ABS problem was a short on the dump solenoid on the blue circuit, not the ECU. But I followed the troubleshooting procedure and found my short. I did have the Info Centre too and that helped, but I followed both procedures for "fun".

Al Jones
'84 M923

 

[govt]

Just downloaded the 23 TMs. Wow! Thanks for the info!

 

[govt]

Just found and fixed my ABS issue on my 931A1. Thanks to jonesal and juanprado for the heads up and location for the ABS TMs. Took 10 minutes to locate issue. Wire leads 1 & 2 had become loose after a gauge swap out. The wires / connectors are in there tight! Reseated, started truck, ABS light came on then went off. Can't wait to drive it without experiencing the bucking on braking. Hoping she stays off after the first drive. Thank you for the help!

 

[emr]

I guess the reason dash lights are called idiot lights is answered in emmado s post, Some drivers did not know when a light lights up on the dash it is something that could be wrong with the truck, when it happens here, i am glad to see guys ask right away , (whats up..what do I need to worry about... .), , because it is a warning light Could be a slow air leak, could be an intermittent air leak in a can, also... just another fyi,... I would like to have those stickers though

 

[TurboMustang370]

A little off topic but: I just had my "new" M932A2 dropped off to the yard. Started right up but its dark already and no time to start going over things. The ABS light stayed on and the buzzer was sounding. I'll be looking in to it and probably asking questions.

 

[rrrr]

Well my abs light came back on. I checked the two fuses, they are ok, I checked the ecu connection its clean and ok, when I start up the truck it goes through it check and its ok. The funny thing is sometimes the light comes on after driving a bit or even after starting and idling a bit.

After doing all this I was watching my gauges and noticed my voltage momentarily go into the red. I just replaced all my batteries so I'm not sure what's going on with the charging system. As I watched the charge go into the high end red for a few seconds the abs light came back on ! After reading the manual the abs system operates between 21-31v. So today I'm going to check the alternator and see if the connections are loose or dirty. I hope that its as simple as a loose alternator connection. The funny thing is when it was in the red I measured the voltage at the batteries and it was 27.2v so its going to take a little more trouble shooting to figure this one out. I did download the 23- tm's and they are much better than the 24- tm's.

I will update after some more work.

 

[commandojeff]

Well my abs light came back on. I checked the two fuses, they are ok, I checked the ecu connection its clean and ok, when I start up the truck it goes through it check and its ok. The funny thing is sometimes the light comes on after driving a bit or even after starting and idling a bit.

After doing all this I was watching my gauges and noticed my voltage momentarily go into the red. I just replaced all my batteries so I'm not sure what's going on with the charging system. As I watched the charge go into the high end red for a few seconds the abs light came back on ! After reading the manual the abs system operates between 21-31v. So today I'm going to check the alternator and see if the connections are loose or dirty. I hope that its as simple as a loose alternator connection. The funny thing is when it was in the red I measured the voltage at the batteries and it was 27.2v so its going to take a little more trouble shooting to figure this one out. I did download the 23- tm's and they are much better than the 24- tm's.

I will update after some more work.

You know I was having the same simptoms as you in your first paragraph when my PCB box was acting up. My abs light would randomly come on, sometimes while driving, sometimes while idle, sometimes it wouldn't at all. Once I changed that box my light has not come on at all. You might want to check your connections and grounds to that box. I never noticed my voltage gauge giving me problems during that time however. So that might be a different issue. Good luck!

Forgot to mention that my symptoms were occuring for several weeks before my box starting giving me trouble with starting the truck. This was basically the beginning stages of my box going out I think. I figured the abs light was due to my back left hub seal leaking. But after changing that box it doesn't come on.

 

[rrrr]

Well I pulled the connectors off the alternator and found the excite wire had the insulation torn! I covered it up put everything back together and it works !

Interesting how a problem can be the result of another issue. I will keep an eye on it though just to make sure.

 

[patracy]

Well I wanted to jump in here for a little advice on my 931.

When I first got my truck, the ABS light was on. Just checking around, I noticed the ABS light connectors unplugged under the dash. Plugged them back in, presto, the truck checks the ABS and it's happy after that. I had driven it around for a bit without any issues.

Yesterday I picked up my M871 trailer. On the way home we noticed the right rear hub and drum being very hot. Also from time to time it felt as though the brakes were holding. Then it would suddenly be ok. The ABS light remains off though (after a normal start/check).

I was planning on pulling the axle tomorrow to check the bearings. (And I'm thinking about ditching the outer seal to make it a wet bearing instead)

So my thoughts are this. Is this indicative that there is a ABS issue on the truck? Seems like disconnecting the ABS warning light might have been intentional. I realize that the brakes might need an adjustment as well. The driver's side rear axle was a little warm as well.

It's my understanding from what I've read that the ABS system only actuates the rear most axle. Also I believe I recalled a blurb about the parking brake also actuates the rear axle parking brake?

 

[Nonotagain]

Chances are that your brake problem is due to a sticky brake wedge.

The ABS system only reads the sensor on the rear axle. Both axles are controlled via the ABS module.

Pull the drum, and sand all the brake gliding surfaces and coat with a high temperature waterproof grease. Don't over due it of you'll be pulling it back apart to clean the pads.

Most if not all of the 931 and 932 tractors sat for a very long time.

I haven't pulled apart one of the brake cans so I can't tell you what takes a dump inside of them.

 

[rrrr]

Chances are that your brake problem is due to a sticky brake wedge.

The ABS system only reads the sensor on the rear axle. Both axles are controlled via the ABS module.

Pull the drum, and sand all the brake gliding surfaces and coat with a high temperature waterproof grease. Don't over due it of you'll be pulling it back apart to clean the pads.

Most if not all of the 931 and 932 tractors sat for a very long time.

I haven't pulled apart one of the brake cans so I can't tell you what takes a dump inside of them.

Correct !


I would try a couple of hard brake pumping actuations to see if you can loosen things up. If that doesn't work then follow what's recommended above. I had the same issue until I did this and drove the truck every so often. Now its great ! I love my tructor

 

[rrrr]

I was able to locate one of the Haldex diagnostic computers. It now sites in my office at home. Any more troubles and is should be a lot easier to figure out what's going on !

 

[patracy]

Chances are that your brake problem is due to a sticky brake wedge.

The ABS system only reads the sensor on the rear axle. Both axles are controlled via the ABS module.

Pull the drum, and sand all the brake gliding surfaces and coat with a high temperature waterproof grease. Don't over due it of you'll be pulling it back apart to clean the pads.

Most if not all of the 931 and 932 tractors sat for a very long time.

I haven't pulled apart one of the brake cans so I can't tell you what takes a dump inside of them.

Correct !


I would try a couple of hard brake pumping actuations to see if you can loosen things up. If that doesn't work then follow what's recommended above. I had the same issue until I did this and drove the truck every so often. Now its great ! I love my tructor

I'll take a look at it tomorrow. (Pull the axleshaft and check free play)

It's been driven about 110 miles on the way home from the recovery. Then 225 yesterday. Just really noticed it pulling the trailer. I doubt it's anything that hasn't "freed up" by now.

On a side note, my trailer brakes weren't releasing quickly either. I pulled the relay valve off tonight and found a ton of dirt and dust that had the valve wedged not allowing it to dump freely. (Release the brakes) I cleaned it up and lubed the orings to see if it just needed a good cleaning. (Apply the brakes works fine, releasing works eventually but slowly)

Any chance if I find the drum sticking on the truck I could get away with just caging the cyl, removing it and the wedge and just lubing up that section? Or do I need to pull the drum off and reset the adjusters and such?

 

[Nonotagain]

Due to the amount of time the trucks sat, I'd pull the drum for a inside inspection.

I'd like to tell you you'd only have to pull the can and the wedge, but not seeing how rusty the other parts were, we'd be taking a SWAG on what's the culprit.

Pull the one then decide of the others also need attention.

IMHO.

 

[wsucougarx]

I am joining this thread because my newest truck has a steady ABS Light. When switching on the batteries, I hear the initial 3 clicks from the rear of the truck. But I do not hear the second series of 3 clicks where the ABS light shuts off. I'm going to try and look at the fuses tomorrow.

 

[wsucougarx]

Well, I'm in the middle of troubleshooting. I am now under the dash checking connections. I decided to check the fuses. The 15 amp looked good then my attention turned towards the Y off the starter switch and the 30 AMP fuse. The 30 AMP fuse looks good...WAIT....30 AMP FUSE?!?!?! Ahh, crud I at this point I'm thinking my ECU must be fried. They were suppose to use a 3 AMP fuse from what I'm reading.

 

[M35A2-AZ]

30AMP....wow!!
Hope it is not toast.