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Discussion Starter #1
I am having major troubles with the brakes/ABS Worked fine until I swapped in the T56, don't know if its related or just a bad coincidence? I get both the brake, and ABS lights on, and fault, brakes displayed on the cluster. Pedal feels softer when light is on, and seems like ABS wont kick in at all, when the code is set.


ABS? I Get a B0222 or C0222 rear channel in release to long?

Dealer says that is a wheel speed sensor, or that its driven in mud or snow. Well it sets on dry pavement, and low speed while cornering, either coasting or braking. Also the pedal pulses like mad, the minute you touch the brakes, the abs kicks in at any speed under about 30 mph.

Could it be the T56 17 tooth reluctor does not have enough resolution to pick up well at low speeds for the Colorado's ABS system? Automatics, and Colorado Ma5 5 speed, and SSR T56 all use a 40 tooth reluctor for better resolution.

How do I determine what wheel speed sensor it is? Or if its the V.S.S which doubles as the rear wheels speed sensor for the ABS

Is it a tuning issue the way I have the speedo settings? I kept the settings the same as they were with the V8 and stock 5speed. Al I did was change the reluctor from 40 to 17? The speedo seems accurate? Is there something else I need to change?
 

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Discussion Starter #3
Thanks Rich, why does my stupid actron scanner say B0222? Dealer say's its C0222. The description on my scanner is way off rear channel in release to long
 

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Discussion Starter #4
I guess I'll try the hammer method, followed by using the one from my wrecked truck
 

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The thing to do, is follow the wiring back to the EBCM. Disconnect it there, and connect an ohmmeter to the sensor side of the wiring. If you get a reading other than infinite resistance, wiggle the wiring with the ohmmeter still hooked up, and see if it goes open. If you get an open reading right away, go to the shorter sensor lead, and check again there. If that reads continuity, there is a break in the secondary lead. If you get continuity at all times, switch to an AC volt meter at the sensor side of the lead at the EBCM. While spinning the wheel fairly quickly by hand, you should get a reading of about 1/2 volt.

If you do, there may be a problem with the EBCM, or with the connection there. If you do not read AC voltage while spinning the wheel. you may have a 2nd faulty wheel speed sensor, or a sensor that's not properly seated, or some sort of debris between it and the Tone Exciter Ring. The gap between the sensor and ring has to be very precise. Any rust buildup or such on the mounting can hold the sensor too far away, preventing a sufficient voltage from being generated. Likewise, rust debris in the teeth of the ring or sticking to the sensor can prevent a voltage from being generated. or make it very weak.
 

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Discussion Starter #6
On the 04-06 the sensor is not removable from the hub, it part of a ring that's pressed on the hub? Can't see how to take it off and romove the corrosion?

Great info rich I will check out the wirring!
 

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Discussion Starter #8
Well I'm confuse!

Either all four of the front wheel speed sensors I have are open, or my multi Meter is not good enough to read that high a resistance. Also none of them make ac voltage when spinning them.

Pretty sure the 04-06 sensors are not ac the abs sends a voltage two both front wheel sensors and then out a signal wire. These sound more like a Hall effect sensor rather then a ac sensor. Not sure how to test them? But the 04 wirring diagram shows the reference voltage sent out I'd common to both front sensors, then the left and right signal wire.

I have no breaks in the wiring from the sensor two the control module, verified by the multi meter.

I replaced the right front wheel bearing and abs sensor from my other truck, it was good before, it still should be.

I'm confident there is nothing wrong with the right front wheel at all!!!!

Moving on, gotta be something with the rear, guess I'm going to Oder a 40 tooth reluctor from a t56 Ssr and mod it to fit the trans! That or change the abs module and left front sensor either way it's gonna be costly

I'm so frustrated waiting three hours changing the right side to no avail!

Do I pull the abs fuse so I can drive it for now?
I need to get a better scanner or a better year specific info

Action cp9580

Reads B0222
Rear antilock brake system channel in release to long
 

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Discussion Starter #9
Is this scanner spitting out jibber jabber? Or is it correct and that's why there is and wasn't anything wrong with the front wheel speed sensors?

The abs comes on the instant you touch the pedal at low speeds, my money is on rear wheel speed, or maybe the rear solenoid is stuck

Perhaps when I drove it with the vss off it broke or jammed something in the pump? Because I was going three to four times faster then what my speedo was reading
 

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Discussion Starter #10
Here is some I info from c fans, I was right about it being Hall effect. My money is a problem with the v.s.s, reluctor or tune


11-22-2010, 05:19 PM #26 (permalink)
Qbasic88
Junior Member

Join Date: Nov 2010
Posts: 1
Re: Help? 5 ABS codes
Hey, I registered here to give some info on these Chevy. I own an autoshop. The EBCM (electronic brake control module) will almost never fail. These vehicles use a 120 tooth ring on the hub and the abs sensor acts as a hall effect. As the tooth ring moves across the abs sensor it creates a square wave pattern that is sent to the EBCM to calculate the tire speed. The other codes mose people get (WITH the typical 45,35's) is for channel i nrelease. What is happening is the EBCM is seeing a difference in the square wave pattern. It thinks the tires are moving at different speeds (and in sense activates the abs at incorrect times). Even if it doesn't activate abs, if there is a signal difference from LF & RF it will set a code for Erratic signal.

Most of the times you can jack the vehicle up and look through the back where the abs sensor bolts to the hub. You will see the 120 tooth gear just inside. If you take a small paper clip and feel in between the teeth you will most likely find a fair amount of rust. This is the cause of the irratic signal. Even if you use a Solus, etc.. & watch vehicle output speed, they will still match. I won't even begin to express how picky the airgap is. Doing a simple front brake job (if you use a hammer to slap the rotor to break it loose) is enough to cause ABS codes to be present that you didn't have before.

There are 2 options available. Getting a hub assembly with ABS sensor already on it (BCA) or you can get seperate hub assembly & sensor (ACDelco). You have to make sure the reluctor ring is ABSOLUTELY spotless. You have to make sure the ABS sensor is seated fully against the hub. If you look there is 2 drains on the bottom of the hub assembly to allow water to drain. Around these heavy winter & salty areas it just corrodes the rings.


You can also use a DVOM (digital volt ohm meter) and check voltage at the ABS sensor connector. It should show 10V. You can wiggle wires up to the connector and you should never see a voltage drop. (That checks wires that could be shorted). I have never seen a EBCM fail. Ever. Hope this helps give some of you a heads up. If you need further info contact my via email [email protected] I have pictures of the rusty hubs in case any of you want to see what I am talking about.
 

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DTC C0220-C0229

Circuit Description

The electronic brake control module (EBCM) energizes the appropriate isolation and dump valve solenoids to control hydraulic pressure applied to a brake circuit during and Antilock Brake System (ABS) event.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

  • DTC C0220 Left Front ABS Channel in Release Too Long
  • DTC C0221 Right Front ABS Channel in Release Too Long
  • DTC C0222 Rear Antilock Brake System (ABS) Channel in Release Too Long
Conditions for Running the DTC

  • The ignition is ON
  • The vehicle is experiencing an ABS event
Conditions for Setting the DTC

An ABS event lasting 36 seconds or longer occurs on any brake circuit.

Action Taken When the DTC Sets

The EBCM disables the ABS/TCS/dynamic rear proportion (DRP).
The ABS indicator turns ON.
The brake warning indicator turns ON.
The ABS fault message is displayed.
The brakes message is displayed.

Conditions for Clearing the DTC

The conditions for setting the DTC are no longer present and you use the scan tool Clear DTCs function.

Diagnostic Aids

Always diagnose and repair any wheel speed sensor failures prior to diagnosing DTC C0220, C0221 or C0222.

These DTCs may set, theoretically, when the ABS is activated on surfaces that are nearly impossible to get traction on. If the DTC sets within these conditions, diagnosis of the ABS system is not necessary.

Test Description

The number below refers to the step number on the diagnostic table:

2: Performing solenoid test determine if there is a mechanical malfunction inside the brake pressure modulator valve (BPMV).​

DTC C0220-C0229
0AsHYiZ0vsVKtdFJJWUV6MTF4XzlzQ2JfSUxWNk82MlE
 

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Discussion Starter #12
Thanks Rich!

Performing solenoid test determine if there is a mechanical malfunction inside the brake pressure modulator valve (BPMV)

That's what I suspect, might try my other ABS unit. I think It may have damaged itself when I drove it with the speedo settings way off!

Otherwise They do say to check wheel speed sensors, but How do you check the rear one, since it is the one I suspect most, the only thing I changed, as everything was working properly with the 5 speed, all I did was swap that out, change the reluctor from 40 to 17 with HP tuners, and wammo I'm hit with ABS problems!

The rear wheel speed sensor is just a calculation of the V.S.S since the 04-06 trucks do not have a rear wheel, or rear diff speed sensor.

I could try a new V.S.S since this one is used, and was full of metal fillings from the old T56. I also notices a few marks in the 17 tooth reluctor, that look like someone hit it with a hammer to remove it!
 

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Discussion Starter #13
Also I just verified the speedo is bang on, I set up Hp tuners, my GPS and went for a drive at 40km hr the the truck reads 42, Hp tuners reads 40, GPS reads 40. At 80 km/hr truck reads 83km/hr HP tuners 80 km/hr, GPS 79 km/hr

Pretty damn close, I'm sure that's all good!

Juts not sure about real slow speed resolution, since I also had to lengthen the V.S.S wires, I soldered and heat shrink ked, and twisted the wires like they originally were. Maybe It needs an extra barrier of tape between the twisted wires, that were heat shirnked?
 

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Discussion Starter #14
Maybe I should try a New V.S.S
 

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Discussion Starter #15
OK borrowed a friends SNap on MT2500. at 11 km/hr my speedo says about 12, both front wheel speed sensors are at 11 km/hr exactly. The rear abs speed reads 6 km/hr! That's the problem!

So I'm guessing the V.S.S must be sent raw to the ABS, and not calculated. Changing the speedo, or rear gear most likely not enough, to trip a code, but going from a 40 tooth reluctor to 17 tooth, is defiantly going to through it out of wack. Hp tuners doesn't seem to show any ABS speed signal adjustments, on the E40 PCm. I'm not sure how to fix this, if I can program the abs, then I have to change the reluctor to a 40 tooth
 

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Discussion Starter #16
OK I kind of fixed it! I set my V.S.S pulse per to 17, and VSS output pulses per to 40,000 and now the scanner reads same speed both fronts, and rear. No code set, no pulsating!

However under really low speeds, 1-2 km'hr I get a minor pulse! front speed sensors show, 1-2 km'hr and rear shoes zero. I think that's because of the 17 tooth low resolution. I'm not to concerned about it, since its at a crawl.

I guessed at 40,000, it was a random number kinda I thought it wants to maybe see 4000 pulses per mile, since that didn't work but it was close, just about 10 times to fast, so I times it by 10= 40000 and it seems bang on!
 

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OK I kind of fixed it! I set my V.S.S pulse per to 17, and VSS output pulses per to 40,000 and now the scanner reads same speed both fronts, and rear. No code set, no pulsating!

However under really low speeds, 1-2 km'hr I get a minor pulse! front speed sensors show, 1-2 km'hr and rear shoes zero. I think that's because of the 17 tooth low resolution. I'm not to concerned about it, since its at a crawl.

I guessed at 40,000, it was a random number kinda I thought it wants to maybe see 4000 pulses per mile, since that didn't work but it was close, just about 10 times to fast, so I times it by 10= 40000 and it seems bang on!
Old thread but great information Jamie.
I am going thru the very same problem here and this confirms my assumption. I only changed the reluctor T count from 40 to 17. I am going to try and change the VSS pulses per mile tomorrow.
According to my calculations the VSS pulses per mile should be set to 44492
 
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