ABS/Brake light "Service Brake System" message on cluster & C0245 when truck reaches 35-40 mph

[Moto826]

Hello all,

I've owned my truck for 4 years now and she's had her fair share of use and abuse. It's a 2005 GMC Sierra 1500 2wd with a 5.3 LM7.

The problem i'm currently trying to solve is that I keep getting an ABS/Brake light, "Serivce Brake System" Message and a c0245 from the EBCM when the truck reaches 35-40mph. The light is NOT on when the truck is started, or when it is turned off and restarted again, it is only present when the truck is being driven. However, the code is still present as a history code when you scan the truck after turning it off.

I had a mishap in 2024 and had to replace the entire rear axle assembly with a junkyard replacement. This changed the axle ratio from 3.23 (confirmed from factory RPO code) to a 3.42 (found RPO code on junkyard donor)

About 2-3 months after replacing the rear axle, the shift solenoids in the transmission went out. Had CEL's related to that. Had it serviced by a well-known, and trusted family-mechanic, as well as purchased an Edge Cs2 tuner to correct the rear axle gear ratio in the ECM & TCM.

However, about 2 years after the rear axle replacement... I'm still getting this light every time I drive the truck over 35-40mph and it has the same issue where it goes away every time the truck is turned back off and on again.

So what the hell is the issue if I've already reprogrammed it?

HP Tuners is unfortunately out of the conversation since I live in California and would like to stay smog legal.

Do I simply need a reprogram of the ABS module with someone that has a scanner capable of doing so? What kind of scanners are capable of this? Am I going to need to search for a tech 2?

I've been hunting this down on google and chatgpt for the last year and a half but I'm hitting a wall and I'm stuck.

Any and all help is appreciated. I'm sorry to drag this whole thing out, I know it's a complicated situation. For those of you that did stick around and read-- thank you, now go crack yourself a beer. You deserve it.

 

[stutaeng]

Are all your tires the same size?

If for some reason tires are different size, the vehicles goes bananas. I put a larger tire on our 13 Chrysler minivan because it had a flat tire, and as soon as I took off heading to the tire shop, the brake and ABS lights turned on.

I was trying to chase some rear rotor runout on my 06 Suburban and jacked the rear up and "ran it" with the front wheels chocked and same thing happened.

Your rear axle doesn't have independent wheel speed sensors, does it?

The axle ratio gets stored on the ECU tune, not on the BCM. You can't regear a tune due to smog regulations?

 

[99Sierra2500]

It might be just a simple bidirectional scanner thing, my foxwell 510 I went into the abs and set the tire size the module calls itself 4WAL, it is by kelsey-hayes.

 

[AuroraGirl]

It might be just a simple bidirectional scanner thing, my foxwell 510 I went into the abs and set the tire size the module calls itself 4WAL, it is by kelsey-hayes.

do you have a gmt400 ? Isnt a 99 2500 a gmt400 still?
That would be logical for the EBC310 yes. but the EBC325, similar but not the only factor


Similar but not same:

Subject: ABS Light On DTC C0055 C0235 C0236 or C0237 Stored In The EBCM Models: 1998-2008 All Chevrolet, GMC, Buick and Oldsmobile Mid-Sized Trucks and Utilities 1998-2008 All Chevrolet, GMC and Cadillac Full Sized Trucks, Utilities, and Vans 1998-2005 Chevrolet Astro 1998-2005 GMC Safari 2003-2008 Hummer H2 This PI was superseded to update model years. Please discard PIT3521D. The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI. [H3]Condition/Concern:[/H3] ABS light on speedometer may be erratic. DTC C0055 C0235 C0236 or C0237 stored in the EBCM. This concern may be intermittent and not easily reproduced. [H3]Recommendation/Instructions:[/H3] Using the Tech 2, check the EBCM, ECM/ PCM and/or TCM for any speed sensor related DTCs. These DTCs will need to be diagnosed first. Follow published diagnostics for related DTCs, repair and evaluate the vehicle after repairs are complete. If no DTCs exist in any other module, inspect the rear VSS sensor circuit(s) from the rear VSS sensor to the related module (ECM, PCM or TCM) for integrity. These circuits are 821 and 822 or 400 and 401 depending on model and model year (use SI to locate the schematic that applies to your application). Repair or restring these two circuits as needed. Evaluate the vehicle.

Subject: ABS Light On, DTCs C0265, C0201, U1041 Set and/or Loss of Communication with Brake Module (Reground EBCM Ground) Models: 2004-2007 Buick Rainier 2002-2006 Cadillac Escalade, Escalade EXT 2003-2006 Cadillac Escalade ESV 1999-2007 Chevrolet Silverado Classic 2000-2006 Chevrolet Suburban, Tahoe 2002-2006 Chevrolet Avalanche 2002-2007 Chevrolet TrailBlazer, TrailBlazer EXT 2003-2006 Chevolet SSR 1999-2007 GMC Sierra Classic 2000-2006 GMC Yukon, Yukon Denali, Yukon XL 2002-2007 GMC Envoy, Envoy XL, Sierra Denali Classic 2004-2005 GMC Envoy XUV 2002-2004 Oldsmobile Bravada This bulletin is being revised to update model years. Please discard Corporate Bulletin Number 04-05-25-002C (Section 05 -- Brakes). [H3]Condition[/H3] Some customers may comment that the ABS light is on. Upon further inspection, DTCs C0265 and C0201 may be set in the brake module. It is also possible for DTC U1041 to set in other modules. There may also be a loss of communication with the brake module. [H3]Cause[/H3] A poor connection at the EBCM ground is causing unnecessary replacements of brake modules. Important: The EBCM Ground is different for each application. Refer to the list below for the proper ground reference: • Midsize Utilities = Ground 304 • SSR = Ground 400 • Fullsize Trucks and Utilities = Ground 110 [H3]Correction[/H3] DO NOT REPLACE THE BRAKE MODULE. Perform the following steps to improve the connection of the EBCM Ground: Remove the EBCM Ground. The EBCM Ground is located on the frame beneath the driver's side door. If multiple grounds are found in this location, the EBCM ground can be identified as the heavy (12-gauge) wire. Clean the area, front and back, using a Whiz Wheel®. Install the ground, then the washer and then the bolt to the frame. Important: It is important to use the bolts, washers and nuts specified in this bulletin. These parts have been identified due to their conductive finish. Install a washer and nut to the back side of the frame. Tighten Tighten the nut to 9 N·m (79 lb in). Cover the front and back side of the repair area using Rubberized Undercoating. An additional check can be made to ensure a good connection for the Battery Cable to Frame ground. It is possible for this ground to cause similar symptoms with the ABS as described above. [H3]Parts Information[/H3] FULL-SIZE TRUCKS, SUVs AND H2​ Part Number​ Description​ 11588564​ Bolt​ 15650962​ Washer​ 15672934​ Nut​ 12378398 (in Canada, 10952414)​ Rubberized Undercoating -- Paintable​ MIDSIZE SUVs​ Part Number​ Description​ 11517555​ Bolt​ 15650961​ Washer​ 11503749​ Nut​ 12378398 (in Canada, 10952414)​ Rubberized Undercoating -- Paintable​

Subject: Unable To Program Tire Size In EBCM/VSES Models: 2003-2006 Cadillac Escalade, EXT, ESV 2003-2006 Chevrolet Avalanche, Suburban, Tahoe 2003-2007 Chevrolet Silverado Classic 2003-2007 GMC Sierra Classic 2003-2006 GMC Yukon, Yukon Denali, Yukon XL, Yukon Denali XL This PI is being updated to add models. Please discard PIT3425. The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI. [H3]Condition/Concern:[/H3] When programming tire size in the ebcm be advised there are three items which must be selected correctly. [H3]Recommendation/Instructions:[/H3] It is very important that when building the Tech 2 that the proper gross vehicle weight (gvw) range is selected. The Tech 2 offers three different GVW options and they are: • "Equal to or Under 8600 GVW" • "Equal to or Under 8600 GVW PHT" (PHT is a Parallel Hybrid Truck RPO HP2) • or • "Over 8600 GVW" If the vehicle is equipped with Stabilitrak RPO "JL4" select "VSES" under the Tech 2 Chassis menu NOT "ABS". On 2005 Model Year vehicles select the proper Rear Brake System "Rear Drum Brakes" or "Rear Disc Brakes". Note: If any of the above items are not selected properly the Tech 2 will not be able to program the tire size and programming will fail.

 

[AuroraGirl]

heres the answer:

[H2]DTC C0241-C0254 or C041-C054 Over 8600 GVW or Rear Drum Brakes[/H2] [H3]Circuit Description[/H3] As the front wheels spin, each wheel speed sensor (WSS) produces an AC signal. The electronic brake control module (EBCM) uses the frequency of the AC signals to calculate each wheel speed. The powertrain control module (PCM) converts the signal from the vehicle speed sensor (VSS) to a 128k pulses/mile signal. The EBCM uses the vehicle speed signal from the PCM to calculate the rear wheel speed. [H3]DTC Descriptor[/H3] This diagnostic procedure supports the following DTC: DTC C0245 Wheel Speed Sensor Frequency Error [H3]Conditions for Running the DTC[/H3] • The ignition is ON. • The vehicle speed is greater than 8 km/h (4 mph). • No brake application or deceleration is detected. • No wheel slip is detected. • No turning maneuvers are detected. [H3]Conditions for Setting the DTC[/H3] • At least one WSS signal is 15 percent less than or greater than other WSS signals. • All of the Conditions for Running and Setting the DTC are present for a cumulative time of 3 minutes during a single ignition cycle. [H3]Action Taken When the DTC Sets[/H3] • The EBCM disables the ABS and dynamic rear proportion (DRP). • The ABS indicator turns ON. • The brake warning indicator turns ON. [H3]Conditions for Clearing the DTC[/H3] The Conditions for Setting the DTC are no longer present and you use the scan tool Clear DTCs function. [H3]Diagnostic Aids[/H3] Installing one tire of significantly different size on the vehicle causes this DTC to set. Operating the vehicle with a tire that has very low air pressure may also set this DTC. Inspect the vehicle for an incorrect or damaged WSS or VSS if the tires and the EBCM and PCM calibrations are OK. [H3]Test Description[/H3] The number below refers to the step number on the diagnostic table. If the front tires are not the same size as the rear tires, the EBCM calibration must match the FRONT tire size and the PCM calibration must match the REAR tire size.

 

[99Sierra2500]

do you have a gmt400 ? Isnt a 99 2500 a gmt400 still?
That would be logical for the EBC310 yes. but the EBC325, similar but not the only factor

An 800, 400 is still made until 2000 also. Unified electronic architecture isn't until 2001, and Allison is still a separate language until 2003. Canbus is 2003. AFAIK

 

[AuroraGirl]

An 800, 400 is still made until 2000 also. Unified electronic architecture isn't until 2001, and Allison is still a separate language until 2003. Canbus is 2003. AFAIK

canbus is not 2003, canbus
Canbus is 2001 starting in duramax trucks for engine uses, then in 2006-7 they had Canbus expand to correlate the cluster and the BCM iirc for one of the Duramax engine options iirc. The other trucks just dont have it. so for example, my 2005 has no canbus

The gmt400 in the later years has class 2... only in minor specific spots.