LA_Z06

I'm trying to follow the instructions for TSB #09-06-03-004E for the BCM where you apply dielectric lubricant to both of the harnesses of the BCM because I keep getting "service active handling/service traction control" on the DIC.

The TSB says to disconnect the black body wiring harness connector FIRST and the gray instrument panel (I/P) wiring harness connector LAST and vice versa for connecting it back again. I think the TSB was meant for another GM car because both of the harnesses are blue so I don't know which is which. Can anyone identify which is the body wiring harness and which is the IP harness on the BCM?



I did a search and couldn't find anything. Thanks.

erick_e

The black harness is the one in the center which needs to be unscrewed.

Just make sure the battery is disconnected and it doesn't matter which one you disconnect first.

Dano523

Ditto, disconnect the battery first.

When you pull the connectors, make sure to clean them and the BCM connectors up with spray electrical contact cleaner before you use the dielectric grease on the connectors.

As for the problem, short of it being one of the Blue connector harness with the harness wire too tight under the passenger carpet that someone is pressing against the carpet to disconnect the connector from the Body control module slightly, would bank that the problem is one of the hub wheel speed connectors instead.

Bluntly, Have you pull the codes to see where the problem was coming from in the first place?

zali0104

Agree Dano with here....
Wires to speed sensor tend to break inside insulation just at the connector. Tug on wires with reasonable force, if wire is broken inside insulation will pop. Check the left front first, tends to be the culprit.

LA_Z06

Codes I'm getting are all ABS codes:

C0161 -ABS/TCS Brake Sw Ckt above max threshold - below min. threshold

C0561 - System disabled information stored invalid serial data received - invalid serial data received

U2107 - Lost communications with body control system

U2100 - Controller area network (CAN) bus communication

Battery was replaced 7 weeks ago. It did die about 3 weeks ago (seat heater for aftermarket seats left on by accident which drained the battery). I drove it around the whole day to make sure it was probably charged and all was good. The car then sat for 2 weeks after that (not on a tender) and I started getting these issues several times in one day and even afterwards, but with less and less occurrence as time has gone by.

So unless the battery didn't like sitting for 2 weeks I can't see this as a battery issue. Voltage is 14.5 while on the freeway and drops between 12 - 13 with the AC on at idle then back up to 14+ while I drive.

Brake lights don't stay on so I'm assuming it's not an issue with the brake pedal position sensor.

I thought I would get a specific wheel speed sensor code if it was the wheel speed sensor.

So by process of elimination I'm thinking it has to be the BCM. It may need the dielectric lubricant, a reflash or a new BCM I'm guessing. Let me know if something doesn't add up here.

Interesting thing is I usually don't have a passenger so no pressure being applied to floorboard where the BCM is.

Is my reasoning pretty sound or am I off on anything?

Thanks, guys.

erick_e

You need to be troubleshooting C0161. All of the other codes are related to the CANBUS communication failure of that module (probably the EBCM).



DTC Descriptor
DTC C0161 00: Antilock Brake System (ABS) Brake Switch Circuit


Circuit/System Description
The electronic brake control module (EBCM) detects inputs from the brake pressure sensor, vehicle speed, and a serial data message from the BCM that the brake pedal is applied. When the vehicle is stopping the EBCM monitors for the brake pedal is pressed, with the brake pressure increasing and the vehicle is slowing down, or when the vehicle is accelerating, the brake pedal is not pressed and brake pressure is not increasing.

Conditions for Running the DTC
• The vehicle speed is greater than 16 km/h (10 mph).

• The ignition voltage is greater than 9.5 volts.

Conditions for Setting the DTC
• The EBCM detects the vehicle speed greater than 21 km/h (13 mph), the brake pedal is Applied for 1 minute , and brake pressure is not increasing.

• The EBCM detects brake pedal is Released and the vehicle speed is decreasing with the brake pressure is increasing.

Action Taken When the DTC Sets
• The EBCM disables the antilock brake system (ABS), traction control system (TCS) and vehicle stability enhancement system (VSES) for the duration of the ignition cycle.

• A DIC message and/or a warning indicator may be displayed.

Conditions for Clearing the DTC
• The condition for the DTC is no longer present.

• The EBCM clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids
The DTC C0161 00 can be set if the brake pedal is applied while accelerating.

Reference Information

Circuit/System Verification
Verify that DTC C0277, or C0278 is not set.
⇒ If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.

Brake pedal unapplied, verify that the brake lamps are not illuminated
⇒ If brake lamps are illuminated, refer to Lighting Symptoms

Replace the EBCM/BPMV assembly.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Brake Pressure Modulator Valve Replacement

• Control Module References for EBCM replacement, setup, and programming

LA_Z06

Interesting. So it possibly comes down to either the EBCM or Brake Pressure Modulator Valve. How exactly do you diagnose this further? Would it be possible to check and see if the EBCM or BPMV is working as it should be with a Tech II?

The other thing I forgot to mention is that the last few times the active handling error has came on, the less codes I've been getting. The first time was the worst and is when I received the four ABS codes I originally posted. Then the second time the only codes that came up were C0561 and U2107. Then this last time only U2107 came up. I don't know if it's just a coincidence or not, but the frequency of the error message has gotten less and less and so have the codes. Don't know if that means anything or not.

erick_e

It's been awhile since I used my Tech2, but you should be able to monitor the brake pressure using the Tech2 and could see if it increases while applying foot pressure.

LA_Z06

Great info, thanks.