How to Fix ABS light on a 2nd-gen Amigo/Rodeo Sport

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How to Fix ABS light on a 2nd-gen Amigo/Rodeo Sport

Postby radare » Thu Jan 21, 2016 3:33 pm

My ABS light has been coming on intermittently on my 2001 Rodeo Sport.

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To pull the ABS codes, I jumped pins 4 and 12 on the OBD-II connector using a short piece of wire:

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I then turned on the ignition key and watched the ABS light for codes. It will flash codes three times each and then move to the next one. The starting sequence flash code is 12 and is flashed as follows: Flash - long pause - Flash - Flash. The ABS code read yielded a bunch of control-module related codes and a pair for the driver-side front speed sensor:

12 (Start of Sequence [Normal])
51 (FL Wheel Speed Sensor Disconnected coil/wiring B-16 )
61 (FL Wheel Speed Sensor Shorted coil/wiring B-20 )
35 (Valve Relay Shorted or disconnected coil/wiring B-9 )
43 (FR Holding Solenoid Valve Shorted or disconnected coil/wiring B-12 )
45 (Rear Holding Solenoid Valve Shorted or disconnected coil/wiring B-14 )
42 (FL Decompression Solenoid Valve Shorted or disconnected coil/wiring B-11 )
44 (FR Decompression Solenoid Valve Shorted or disconnected coil/wiring B-13 )
46 (Rear Decompression Solenoid Valve Shorted or disconnected coil/wiring B-15)


With the codes pointing to a likely failure of the EHCU, I decided to pull it and repair it.

The EHCU (ABS Control Module) is located in the engine bay and attached to the side of the ABS hydraulic unit:

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Removing it was fairly straightforward: Remove three electrical connectors and then four (4) Torx T-20 screws. Then pull it toward the rear of the truck and lift it out around the brake lines.

I took the ECHU inside and cleaned it up with a damp rag to ensure I didn't get any grime in it when I took it apart. Here's the ECHU in all its glory; its a Kelsey-Hayes unit:

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I then took it apart. It's held together with six (6) Torx T-8 screws. I removed those screws and then used a razor blade to cut through the sealant holding it together.

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I had to go around the thing about 100 times with the razor before cutting through all the sealant. I then used a butter knife to separate the two halves and pulled the thing apart:

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In inspected the solder joints with a magnifying glass. I found three that were showing sings of cracking. All were located on solder joints to the connectors. I've added some arrows to show where mine were cracked:

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I used a run-of-the-mill pen-type solder iron and heated up each of the solder joints for all of the connectors, reflowing solder into the joint. I then spent another half-hour cleaning as much of the silicone from the ECHU as possible. Here it is, resoldered and ready to be put back together:

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I applied some black adhesive silicone to the aluminum half of the case and reassembled. I then installed the screws and let it dry overnight.
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This morning, I reinstalled the ECHU and took the truck for a 50-mile drive. No more ABS light!

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Last edited by radare on Fri Jan 22, 2016 2:01 am, edited 1 time in total.
'94 Isuzu Rodeo 4WD, 3.2L V6. 156k miles (Sold); '01 Isuzu Rodeo LS 4WD, 3.2L V6, 108k miles (Sold).
Currently restoring an '01 Rodeo Sport V6
My other passion: My Yamaha XJ600 and XJ600 Scrambler

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Re: Fixing ABS light on a 2nd-gen Amigo/Rodeo Sport

Postby totten » Thu Jan 21, 2016 11:31 pm

Great job! Impressed with your work. Saved you a lot of money. Thanks for the pictures too.
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Re: Fixing ABS light on a 2nd-gen Amigo/Rodeo Sport

Postby radare » Fri Jan 22, 2016 1:53 am

I purposefully slid on some ice today and let the ABS kick in. The system worked perfectly and no ABS light came on in the process. I'm going to say this one is a success!
'94 Isuzu Rodeo 4WD, 3.2L V6. 156k miles (Sold); '01 Isuzu Rodeo LS 4WD, 3.2L V6, 108k miles (Sold).
Currently restoring an '01 Rodeo Sport V6
My other passion: My Yamaha XJ600 and XJ600 Scrambler
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Re: How to Fix ABS light on a 2nd-gen Amigo/Rodeo Sport

Postby radare » Fri Jan 22, 2016 1:13 pm

It should be noted that this fixed both the ECHU codes and the two for the front-left speed sensor (51 and 61).
'94 Isuzu Rodeo 4WD, 3.2L V6. 156k miles (Sold); '01 Isuzu Rodeo LS 4WD, 3.2L V6, 108k miles (Sold).
Currently restoring an '01 Rodeo Sport V6
My other passion: My Yamaha XJ600 and XJ600 Scrambler
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Re: How to Fix ABS light on a 2nd-gen Amigo/Rodeo Sport

Postby MonsterD » Wed Jan 27, 2016 2:41 pm

Great Post! I imagine this would be the same process for the Trooper other than the lack is easy access to the ECHU.
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Re: How to Fix ABS light on a 2nd-gen Amigo/Rodeo Sport

Postby radare » Fri Jan 29, 2016 2:20 am

MonsterD wrote:Great Post! I imagine this would be the same process for the Trooper other than the lack is easy access to the ECHU.

Should work for all models which use the Kelsey Hayes controller and which are returning EHCU trouble codes. Sucks that accessibility isn't better on the Trooper.
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My other passion: My Yamaha XJ600 and XJ600 Scrambler
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Re: How to Fix ABS light on a 2nd-gen Amigo/Rodeo Sport

Postby Ed92Rodeo » Sun Jul 10, 2016 4:32 pm

Thanks for the detailed writeup! I'm about to tackle mine, 2002 Rodeo LS 3.2.

I had the same problem on my '88 Jag for the brake lights. It was the solder on the pins of the connector joining two circuit boards, located in the right rear fender. Got pulled over for no brake lights and the cop almost drew his weapon on us when my sis-in-law went to step out of the car, not knowing the cop was approaching. Crimeny, it was just a flippin' brake light!

At least an ABS trouble light doesn't warrant a traffic stop. Yet.
-Ed
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02 Rodeo LS strong 3.2, 4WD, all auto everything, wandered into the yard March 2016 (Hers)
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Re: How to Fix ABS light on a 2nd-gen Amigo/Rodeo Sport

Postby Ed92Rodeo » Sun Jul 10, 2016 10:49 pm

Well, it seems to have worked. The ABS light was showing up before we hit the highway only 1/8th mile away, on about anytime I looked. Not like I care, but any dash light bugs the missus. And it might matter on ice if suddenly caught on a patch near a stoplight, which is kinda common around here in the city during winter.

My disassembly was much like the photos, with the addition they embedded the lower third of the circuit board in that stretchy sticky stuff that holds your new credit card onto the letter it comes attached to. Not silicone, thank god, but it really puckered the lid down and I had to pry a lot and reach in with a knife and slice it away to open it.

After that, good heat and clean tip on the iron and fresh solder. Reinstall. Done. I didn't reseal the lid, may need to revisit. Under the hood of this 2002 is so clean, I'm not worried. I left the old rubber sealant in place, looked like it would reseal well enough. Won't know for sure till I take a longer drive, but lookin' good so far. If it's good, looks like this saved me an easy couple hundred bucks for the ABS module. THANKS!
-Ed

EDIT: The ABS light is banished, hopefully to never shine again. Tested it in a low speed slam-stop on gravel and it pulsed the pedal, preventing me from skidding to a stop. BTW: In another thread, someone suggested just unplugging the module to shut off the light and disable the ABS. I had to move the Rodeo after pulling the module, and the ABS came on and stayed that way till the second time I started it after the fix, when it went out a few seconds after starting the engine.
92 Rodeo LS, venerable 3.1, 4WD, 139k, owned since 94 (His)
02 Rodeo LS strong 3.2, 4WD, all auto everything, wandered into the yard March 2016 (Hers)
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Re: How to Fix ABS light on a 2nd-gen Amigo/Rodeo Sport

Postby mattallen1007 » Mon Apr 10, 2017 9:45 pm

Great post! Stumbled upon it last night, resoldered the module in my son's '02 Rodeo today. I was pessimistic, but decided I had nothing to lose but an hour of my time. No more ABS codes (had a dozen) and ABS functioned properly on an attempted gravel skid. Amazing. I had pulled a junkyard module previously, it threw a dozen or so similar codes as well. I now realize it had also likely failed in the same way. At some point, I will resolder it and see what happens. Hopefully will end up with a functional spare even..

I know this post is older, but wanted to add the following note for future finders: There are 8 spots on the circuit board that correspond with raised sections on the inside of the aluminum cover. There's a hardened dried white substance on these areas. I believe these are heat sink contact points, to help dissipate the heat created by the electronics in this sealed unit. Some cursory research leads me to believe the heat sink compound (white stuff) should probably be more pliable than mine was, and also be continuous between the surfaces (once dried out and then separated, it's going to lose effectiveness). I ordered some "thermal grease/heatsink compund paste" online, and intend to scrape the old off (mostly stayed stuck to the cover- should help) and reapply. I'll also silicone seal the cover edges at that time. Hopefully this will aid in the long-term effectiveness of this repair..
Last edited by mattallen1007 on Sun Apr 16, 2017 12:06 am, edited 1 time in total.
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Re: How to Fix ABS light on a 2nd-gen Amigo/Rodeo Sport

Postby radare » Wed Apr 12, 2017 7:10 pm

mattallen1007 wrote:I know this post is older, but wanted to add the following note for future finders: There are 8 spots on the circuit board that coorespond with raised sections on the inside of the aluminum cover. There's a hardened dried white substance on these areas. I believe these are heat sink contact points, to help dissipate the heat created by the electronics in this sealed unit. Some cursory research leads me to believe the heat sink compound (white stuff) should probably be more pliable than mine was, and also be continuous between the surfaces (once dried out and then separated, it's going to lose effectiveness). I ordered some "thermal grease/heatsink compund paste" online, and intend to scrape the old off (mostly stayed stuck to the cover- should help) and reapply. I'll also silicone seal the cover edges at that time. Hopefully this will aid in the long-term effectiveness of this repair..


Great advice there, mattallen. I used some heat-sink paste I had from a computer processor replacement when I did mine.
'94 Isuzu Rodeo 4WD, 3.2L V6. 156k miles (Sold); '01 Isuzu Rodeo LS 4WD, 3.2L V6, 108k miles (Sold).
Currently restoring an '01 Rodeo Sport V6
My other passion: My Yamaha XJ600 and XJ600 Scrambler

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Re: How to Fix ABS light on a 2nd-gen Amigo/Rodeo Sport

Postby OlRob65 » Thu Apr 13, 2017 1:31 pm

Good information. My ABS light is on too. Since the unit works I'll fool with it when I feel up for a challenge.
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Re: How to Fix ABS light on a 2nd-gen Amigo/Rodeo Sport

Postby zuoverlander » Fri May 12, 2017 11:49 am

Hey guys, great info. My '02 Trooper ABS light starting coming on 2 months ago and stayed on 2 wks later. I may attempt this repair myself. I'm just anal enough that it does bug me! appreciate the info!!
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