Haldex Infocentre ABS diagnostic connector

[ichudov]

My M927 displays a constantly lit ABS light.

I bought a "Haldex Infocentre" that is supposed to aid me in diagnosing this problem.

I did read the Infocentre manual as well as the ABS TM. However, I still have not understood where is the connector located on the truck? In the cab, in the engine compartment, or where?

thanks

and sorry if this is a dumb question

 

[goldneagle]

Passenger side of cab under the dash.

 

[ichudov]

Passenger side of cab under the dash.

OK, awesome, thanks a lot!

 

[Suprman]

There is a handheld diagnostic tool it's like one of those little handheld obd2 car scanners it's made by haldex

 

[ichudov]

Hello, I went to check out my truck today. It does have a "Haldex" connector on the passenger side under the dash.

I bought a brand new Infocenter.

However, the connector on the truck is a four male pin connector. My Infocentre plug is two pin male and does not fit the connector. What is up with that?

In the package with the Infocentre that I bought, these is also an adaptor with two alligator clips, maybe I can hook them up to something?

Would love to get some pointers. Thanks

 

[Suprman]

This is what my haldex reader looks like mine came from a surplus seller the plug may be different on the military trucks compared to civ versions I havent seen any others

 

[ichudov]

Well, I tried checking out the fuses. I found a 3A fuse (good) and a 15A fuse (blown). Replaced it with a 15A fuse from my pickup, and the new fuse blew right away.

Does it mean that I have a "Blown ECU"? Right?

And if so, what are my realistic options. Does Haldex still sell replacements?

 

[Suprman]

I have never worked on the abs system but it cant be that hard. If you can find a schematic diagram or troubleshooting guide it can be worked thru. Where were the fuses and were they with the abs ecu?

 

[camoyj7]

Maybe the power wire is rubbed through some were and shorting out.

 

[ichudov]

Maybe the power wire is rubbed through some were and shorting out.

Yes, that's possible. To test this, I need to disconnect the harness at the ECU (above rear axles) and test for short to ground, right? thanks

 

[juanprado]

I would recommend searching "motherload" in the 5 ton forum. There is a new 5 part set of -23 repair TM's available just released in Sept that are not posted here but the thread will show you were to download. they have very effective trouble shooting flow charts. On the ABS, they specifically have a flow chart with and with out the info center for diagnostics. The abs was added to the trucks and the manuals posted here do not have the reapir and diagnostic info. ECU and electronics at the valves are best sourced from another ss member parting a truck as they are expensive and 24v. napa has the sensors, valves, and exciter rings. Everything is made by Midland/haldex. They can order the other goodies but it requires a platinum amex.

Wiring issue can be a bad ground, bad power feed from PCB, bad sensors, valves etc. many possibilities before you start throwing parts at it.

 

[ichudov]

I would recommend searching "motherload" in the 5 ton forum. There is a new 5 part set of -23 repair TM's available just released in Sept that are not posted here but the thread will show you were to download. they have very effective trouble shooting flow charts. On the ABS, they specifically have a flow chart with and with out the info center for diagnostics. The abs was added to the trucks and the manuals posted here do not have the reapir and diagnostic info. ECU and electronics at the valves are best sourced from another ss member parting a truck as they are expensive and 24v. napa has the sensors, valves, and exciter rings. Everything is made by Midland/haldex. They can order the other goodies but it requires a platinum amex.

Wiring issue can be a bad ground, bad power feed from PCB, bad sensors, valves etc. many possibilities before you start throwing parts at it.

Hi, I did read the TM pertaining to ABS troubleshooting.

What I can say is that my truck "looks new" and clearly was very recently rebuilt. Some panel components are dated 10/2012.

I did dive under the rear of the truck and everything I saw, everywhere, indicates that it was not abuse and likely not even used much. So, I think that it is unlikely to expect issues related to wire wear and abrasion.

That said, I am not going to argue with you, because you are right and I need to do more troubleshooting before starting to buy expensive parts. However, I do anticipate what the ultimate answer will be -- the ABS ECU is likely toast. But I will try to eliminate other possibilities like shorted wires.

 

[Suprman]

If its the ecu that's blowing fuses if you disconnecting it and put a new fuse it, then it should not blow. If the fuse still blows I would start tracing the 15 amp circuit and see where it goes. Depending on how the yellow light is wired a dead ecu may not light it. If there are 2 fuses it would make sense that the lower current one runs the ecu and the higher current one runs air control to modulate the brakes. Probably a bank or banks of solenoid valves check over the rear axles it should have an electrical connector going to it along with air lines. Take the smaller fuse out see if the abs light goes out. If it does then it would appear the ecu is powered and is recognizing a fault. When these trucks sit with moisture in the air system it corrodes and gunks everything in the air system up.

 

[ichudov]

OK, so, it would make sense to try disconnecting the ECU harness at the ECU, and try another fuse. I will try that tomorrow, though it will be a busy day.

 

[ichudov]

As I mentioned earlier, the 15 amp fuse going to my Haldex ABS ECU was blown, and a replacement fuse also blew right away when I powered up the truck after fuse change.

To try to see if this is the ECU, or the wiring leading to it, that causes the short, I disconnected the ECU today. I have to, sad to say, report that with the ECU disconnected, the fuse does not blow. So, my conclusion is that the ECU is bad.

So, my option is to find a new or used one as a replacement...

Thanks to all for your help and encouragement...

And, finally, will ebay item 310419991495 be a good replacement?

 

[Suprman]

I have never messed with the abs system. Someone said if you search motherload there was possibly a newer tm with an abs troubleshooting guide. Things are not always what they appear to be with electrical issues before I ordered any parts I would follow the troubleshooting procedure. You could be brave and swap the ecu from your other truck and see what happens.

 

[jonesal]

Ya, get the proper TM and its walks you through troubleshooting without the Haldex reader. It's pretty comprehensive.

Al Jones
M923

 

[ichudov]

OK, guys, sorry for shouting, but I AM EXTREMELY HAPPY TO REPORT THAT A NEW ABS ACU UNIT FIXED MY PROBLEM!!!!!!!!!!!!

I bought a replacement unit on eBay. It arrived in a new sealed condition. I installed it, which was almost trivial. I had to disconnect old hoses, bring old unit in, move hose connectors from old unit to new, install new unit, connect hoses, connect electricals, replace the fuse with a new 15 amp fuse and I am done! No more ABS light!

Thanks to ALL for your help!

Now, I am wondering, has anyone bothered to open an ABS controller to see what is inside? Is board level repair possible?

 

[engineer233]

Be careful when you shut down your truck. Always kill the engine completely , then the battery switch. If done improperly it can send a voltage spike through the system and zap the ecu again or other goodies.

 

[ichudov]

Be careful when you shut down your truck. Always kill the engine completely , then the battery switch. If done improperly it can send a voltage spike through the system and zap the ecu again or other goodies.

Yep, painfully aware of this now. It is a design defect of the truck, in my opinion.

Would anyone recommend a good protective circuit for this?