I've made a couple threads on my issue before but i've narrowed it down a little better so here it goes...

Code 0561 and Code 0161.
It seems to me that the pedal switch and the EBCM are not communicating properly. I am worried that the dealership is going to charge me an arm and a leg for diagnosis so I figured you guys could shoot me some ideas.

My ABS/TC/AH lights all come on everyday, intermittently. They mostly come on when the car is up to normal running temperature and exceeding 70mph for the first time after start up. If the car is shut off, the ABS codes get cleared and it looks like nothing is wrong. If i'm cruising down the road under 70 mph and I push the TC button once, it flashed "service TC system" on the dash, but still shuts off TC as it should. EVERY time I start the car it says "Service Vehicle Soon" instantly. This issue has been going on for 2 months now and i'm loosing my mind. I am thinking about replacing the EBCM and brake pedal switch and be done with it. I don't know what else it could be.

ANY ADVICE WOULD BE GREATLY APPRECIATED!

 

I saw your other thread and posted a question about why you thought you needed the EBCM repaired.

Now that I see your problem, you may well have some kind of EBCM or BPMV problem, but I doubt it very much.

The first thing I would recommend is that you get your battery evaluated. What you are experiencing sounds similar to problems owners have when the battery is getting weak or has a bad cell.

The second thing is that it sounds more like an AH/TC issue. There a mega-bazillion threads about your problem, or very similar problems. There is a TSB about the "Service Active Handling" message:

http://www.corvetteactioncenter.com/...Message+on+DIC


I believe there was an earlier bulletin about the C0561 code on earlier C6 model years and a reflash of the software in the EBCM.

So, do a search for "Service Active Handling" and "Service Traction Control" or "Service Traction System" and you'll find hundreds of threads about the problems.

Commonly this is an electrical connection problem (the connector under the steering column for telescoping steering wheels, grounds, weak battery, etc.), and not necessarily an EBCM problem.

Good luck!!

Bob

 

Alright I'll get the battery tested tomorrow. I might give in and take it to the dealership to have them scan it for me with a tech2. Tha js for the help everyone! I'll post update tomorrow and hopefully get this figured out

 

Alright so I took it to the stealership. After a lot of hassle and two days of them running me around...
Code p0040 RF wheels speed sensor

They diagnosed the issue to be either the wiring between the small 3 foot harness that plugs into the rf wheel speed sensor or the EBCM is bad. They ran jumper harnesses across te front to trick the sensors. So rf harness was plugged into the left side sensor and the LF harness was plugged into the RF sensor. Cleared codes and drive it. It was still throwing the RF wheel speed sensor code 0040. So I'm going to re-pin and run two new wires from the EBCM to the RF wheel speed sensor. If it still throws the code I believe it's the EBCM that is bad..
BTW the RF wheel speed sensor was tested for resistance and the small 3 for harness that plugs into it was checked for proper resistance and they were both good. No cracks in small harness or exposed wires. Let me know what you guys think. Hopefully this nightmare will be over soon

 

Buying parts will be expensive. The speed sensor is part of the bearing/hub asy. See below from the service manual. the cost of the bearing/hub asy is GM retail but you can get it cheaper at a parts store. This is a snapshot from one of the TSB's. There are others.

Front Wheel Speed Sensor Replacement

The front wheel speed sensors are integral with the hub and bearing assemblies. If a speed sensor needs replacement, you must replace the entire hub and bearing assembly. Do not try to service the harness pigtail individually because the harness pigtail is part of the sensor. Refer to Front Wheel Bearing and Hub Replacement (See: Maintenance\Wheels and Tires\Wheel Bearing\Service and Repair\Front Suspension) .

Wheel Speed Sensor

Front Speed Sensor

Includes: Front Wheel Hub.

88967287

$497.50

Bulletin No.: 08-05-25-004A

Condition

Some customers may comment that the Antilock Brake System (ABS), Traction Control System (TCS) or StabiliTrak(R) (if equipped) warning lights are illuminated. Upon investigation, one or more of the following DTCs may be in history or current.

Correction

Begin diagnostics with the component test procedure listed below. If the cause is not found, proceed to the Circuit/System Testing on the applicable Diagnostic Information and Procedures document for the vehicle you are working on. SI Diagnostic Information and Procedures are being revised to reflect this change in strategy.

1.

With the ignition OFF, disconnect the harness connector at the appropriate wheel speed sensor.

2.

Test for 850-1350 ohms between the signal terminal A and the low reference signal terminal B. During the test, check for an intermittent circuit condition by gently moving the wheel speed sensor pigtail harness. If not within the specified range, replace the wheel speed sensor.

3.

Test for infinite resistance between each terminal and the steering knuckle. Reverse the test leads, test for infinite resistance between each terminal and the steering knuckle again. If less than the specified value, replace the appropriate wheel speed sensor.

4.

Spin the wheel while monitoring the voltage between the signal terminal A and the low reference terminal B. The voltage should be greater than 100 mV AC. If less than the specified range, replace the wheel speed sensor.

Parts Information BCM

Body Control Module

P/N 20759656

$320.46

 

I forgot to mention that the bearing/hub asm is covered under your 5 year 100,000 mile warranty. You didn't mention what year your car was.

I had a wheel speed sensor go on my '07 Silverado this summer and they fixed it under warranty by replacing the bearing/hub asy (of which the speed sensor and pigtail is an intregal part).

 

RF wheel hub assembly was already replaced. Resistance had been tested an is good.

 

2005. No warranty

 

My two options:

So my local shop quoted me $250-300 to change the two wires from the EBCM to the RF wheel speed sensor harness.

If that doesn't fix my issue then it has to be the EBCM that is bad. Which I can pickup used for $250-300.

My question is.... Who thinks it's the EBCM and who thinks it's the wirs that are bad in the harness?

And does anyone know what size/gauge the wires are from the EBCM?

 

Based on your comments I assume you are talking about DTC C0040. You should use the correct leading character when you have DTC discussions because the numerical part of the code can be duplicated several times.

It seems they have isolated the fault down to the EBCM harness or the harness connector near the wheel speed sensor. It is more likely the problem resides in the connector and not the harness so you should start with trying to get a good connection. If you do some searching in the C5 sections of the forum you can find some pictures and suggestions provided by Bill Curlee on how to resolve problems in those connectors.

What happened to the two codes that you started the thread with? As you mentioned the C0161 tells you something is going on with the brake pressure sensor while C0561 is telling you there is a problem with the engine controls that is preventing TC from operating. Traction Control is a function of two subsystems in the car. The ABS Subsystem and the Powertrain Control Subsystem. This DTC informs the mechanic this traction control issue is isolated to the Powertrain Subsystem.

See the attached diagnostic procedures.

Bill

 

I forgot to mention that C0161 and C0561 were a result of the brake switch needing to be calibrated. The dealer did that and no more issues so far. The Wheel speed sensor harness is now the issue

 

Bill, as far as "good connection", when the dealer drove my car they had the scanner running and they said the RF was reading properly but it's possible that it could be such a quick fallout in connection that he won't see it in the scanner because the sampling rate is simply not fast enough.

So should I just go buy a set of male/female connectors from the auto parts store and splice/heat shrink them into where the main harness connects to the mini (approx 3 ft) wheel speed sensor harness?

 

Tonight when I started my car it was pouring rain outside. Upon startup it said Service AH and Service Vehicle Soon. This leads me to believe moisture is messing with the plugs.... Tomorrow I'm going to wire in some new plugs and use some dielectric grease...anyone have any advice?

 

Moisture is one of the issues discussed in the procedure. There are ways to make sure the connector pins are making contact besides splicing in new connectors.

Here is a link to one of Bill Curlee's posts on cleaning the ABS connectors:
http://forums.corvetteforum.com/1554253292-post143.html

Bill

 

Thanks Bill. I'll definitely checkout those connectors tomorrow. Prior to today in the rain. The AH lights wouldn't come on til 70-80 mph. So this makes me think it's my tire size because it's so consecutive. It not like I hit the exact bump to make the wires shake and lose connection every time I hit 70mph. I'm running BFG G Force KDW 255/40/18 front and new Firestones in rear 285/35/19 (factory size). I know I need front tires. Maybe I'll go ahead and order them....

 

Checked codes this morning..

B0161
B0561
B0040

I thought B0161 and B0561 would be gone because the dealer recalibrated my brake switch

 

You mean C not B for above i assume.

 

The scanner at advance auto said B...

 

I am assuming you meant C instead of B for the preface character in those codes. C0040 is the only code that will shut down all 3 functions (ABS/TC/AH) of the EBCM. If it didn't exist then C0561 would shut down TC and the TC light on the IP would be on but the ABS would still be able to function.

Depending on what is causing the C0161 code the BCM may be initiating the C0561 code by telling the EBCM that it will not permit TC to operate. The scenario would be something like this: The BCM receives a signal from the BPP telling it if the brake pedal is being applied or has moved from its rest position. (Note:I am not using BCM and EBCM interchangeably.) The BCM then sends messages to other modules based on that input. If the BCM is receiving a signal the brake pedal is being applied when it normally should not be applied it might send a signal to the EBCM telling it there is something wrong thus causing the C0561 code. You should see other symptoms.

Does your cruise control function properly? Are your brake lights on all the time? If you pull up on the brake pedal will two of the codes go away?

Bill

 

The car has a Chinese brake switch in it when I bought it. I was at the dealer two days ago and they calibrated it. The rest of the day it was golden. Then yesterday it started throwing 0161 again. I think the brake switch is bad song ordered a GM replacement. I'll install it Tuesday an go from there.

Yes my brake lights would come on under acceleration sometimes from what people behind me tell me. Cruise control disables when sometimes... I think it's when 0561 is thrown, but not sure. I don't have a scanner so trips to advance auto are frequent