Tech 2 showing multiple DTCs - Related?

[DaveO9]

2013 Tahoe LT, 5.3. 198K miles. I've posted previously about a DIC message I repeatedly get on "Service Parking Assist." The system consistently works fine - all four sensors are triggering when appropriate, but the messages are annoying and I'm still wondering if there are underlying problems. I've replaced sensors and the harness in the bumper. This issue is partly what drove me to purchase a clone Tech 2.

Running full diagnostics with the Tech 2, I get three DTCs on the parking assist: sensors 2,3,4 (not 1) all give a message about sensor short to battery. But I'm getting several others that at first I thought were unrelated to the parking assist, but now I'm wondering if there are any connections between any of these. Note that I am NOT experiencing ANY symptoms. I have not noticed any missing/not working functionality on any of the systems. Here's the list:

- HVAC Control Module; B0423, Symptom 04, Temperature Control 2 Feedback Circuit open.
- Passenger door switch, B2555, Symptom 01, Passenger Compartment Lamp Control, circuit short to battery
- Driver door switch, B2555, Symptom 01, Passenger Compartment Lamp Control, circuit short to battery
- ECBM; C0900, Symptom 00, Device 1 Voltage High

I've cleared all DTCs and these four just come back as soon as I drive the vehicle.

Is there a module, harness, connector, etc. somewhere that could be causing all or some of these things at once? Again, everything works fine. Have not noticed any issues with any systems, door locks work fine, HVAC good, both front and rear controls, interior lights go on and off with doors open/closed as expected, etc.

There is one symptom I have noticed, however. I will get a DIC message about "battery low, start engine" very quickly when doing diagnostics with key on. We're talking just a couple minutes. Very consistent. But when I start the engine, starter doesn't drag at all and engine starts normally. My 2009 Tahoe would let me keep interior stuff on much longer before I got that message. Battery could be going, I think it's about 3-4 years old.

Thanks.

 

[OR VietVet]

IMO, you need to do a search and go thru the "grounds" threads and start there. These codes all seem to point at circuitry problems. Likely related to grounds problem or a connector problem or a short to ground power wire.

 

[Joseph Garcia]

It would be best to keep all of your posts in your original thread, rather than opening a new one on the same topic.

 

[swathdiver]

2013 Tahoe LT, 5.3. 198K miles. I've posted previously about a DIC message I repeatedly get on "Service Parking Assist." The system consistently works fine - all four sensors are triggering when appropriate, but the messages are annoying and I'm still wondering if there are underlying problems. I've replaced sensors and the harness in the bumper. This issue is partly what drove me to purchase a clone Tech 2.

Running full diagnostics with the Tech 2, I get three DTCs on the parking assist: sensors 2,3,4 (not 1) all give a message about sensor short to battery. But I'm getting several others that at first I thought were unrelated to the parking assist, but now I'm wondering if there are any connections between any of these. Note that I am NOT experiencing ANY symptoms. I have not noticed any missing/not working functionality on any of the systems. Here's the list:

- HVAC Control Module; B0423, Symptom 04, Temperature Control 2 Feedback Circuit open.
- Passenger door switch, B2555, Symptom 01, Passenger Compartment Lamp Control, circuit short to battery
- Driver door switch, B2555, Symptom 01, Passenger Compartment Lamp Control, circuit short to battery
- ECBM; C0900, Symptom 00, Device 1 Voltage High

I've cleared all DTCs and these four just come back as soon as I drive the vehicle.

Is there a module, harness, connector, etc. somewhere that could be causing all or some of these things at once? Again, everything works fine. Have not noticed any issues with any systems, door locks work fine, HVAC good, both front and rear controls, interior lights go on and off with doors open/closed as expected, etc.

There is one symptom I have noticed, however. I will get a DIC message about "battery low, start engine" very quickly when doing diagnostics with key on. We're talking just a couple minutes. Very consistent. But when I start the engine, starter doesn't drag at all and engine starts normally. My 2009 Tahoe would let me keep interior stuff on much longer before I got that message. Battery could be going, I think it's about 3-4 years old.

Thanks.

Your battery has lost its reserve capacity. Fire up the Tech-2, build the vehicle and go to BCM, then BCM again and select Charging Info. In there look at the "state of charge" and "start up state of charge". GM considers the battery done for when it's state of charge is below 65% if memory serves.

I would say that the DTCs are unrelated. Are they all current or any historical? I've had the B2555 before in my pickup and the solution was new bulbs after pulling the mount down and checking everything out.

The actuator code is for the passenger side temperature control.

The EBCM MIGHT be related to your battery being on it's way out.

Get a subscription to AllDataDIY for the shop manual and use that with the Tech-2 to solve those backup sensor codes.

 

[DaveO9]

IMO, you need to do a search and go thru the "grounds" threads and start there. These codes all seem to point at circuitry problems. Likely related to grounds problem or a connector problem or a short to ground power wire.

Yeah, I was writing out that post I did wonder about it possibly being a bad ground somewhere. My guess is the troubleshooting Swathdiver is recommending will explore that possibility. Thanks.

It would be best to keep all of your posts in your original thread, rather than opening a new one on the same topic.

I considered that, but really a different topic. after replacing harness and sensors, I don't think the problem is isolated to the park assist system. It sure seems like the problem I'm posting about here is causing the park assist problem as a symptom. Or possibly the stuff on this post is a whole different set of problems.

Your battery has lost its reserve capacity. Fire up the Tech-2, build the vehicle and go to BCM, then BCM again and select Charging Info. In there look at the "state of charge" and "start up state of charge". GM considers the battery done for when it's state of charge is below 65% if memory serves.

I would say that the DTCs are unrelated. Are they all current or any historical? I've had the B2555 before in my pickup and the solution was new bulbs after pulling the mount down and checking everything out.

The actuator code is for the passenger side temperature control.

The EBCM MIGHT be related to your battery being on it's way out.

Get a subscription to AllDataDIY for the shop manual and use that with the Tech-2 to solve those backup sensor codes.

Thanks for all the input. I'll do the battery check as you suggest.

As for history vs current: HVAC one is current. But the door switch and high voltage ones are historical. I think. It says they passed on last test and then there's a "since clear: history"

I think I should probably spring for the All Data subscription. Just trying to decide on length of subscription.

 

[OR VietVet]

Minimum AllData is 1 year, I think, but price gets discounts with extra time. I was on AllData 1 year and then renewal was double or more than double, IIRC.

 

[Doubeleive]

probably more than 1 poor ground for most of those
I would look at the gm upfitter guide wiring diagrams and find where the grounds are for the backup sensors and start there with a ohm meter. same for the interior lights passenger side.
i assume you meant ebcm? electronic brake control module, you might want to check that the harness is clean no corrosion or water intrusion, inspect the harness for any pinched or chaffed wires.

hvac is likely a actuator not working 100%, sometimes they can error out and still work acceptably, so unless you are getting froze out inside I would leave that one be for now and tackle it later.

you could look online for any tsb's that mention the backup sensors as they usually have pictures and known spots to look. same for interior lights, could be a lamp holder shorting to the body or anything as simple as that

 

[swathdiver]

Yeah, I was writing out that post I did wonder about it possibly being a bad ground somewhere. My guess is the troubleshooting Swathdiver is recommending will explore that possibility. Thanks.

I considered that, but really a different topic. after replacing harness and sensors, I don't think the problem is isolated to the park assist system. It sure seems like the problem I'm posting about here is causing the park assist problem as a symptom. Or possibly the stuff on this post is a whole different set of problems.


Thanks for all the input. I'll do the battery check as you suggest.

As for history vs current: HVAC one is current. But the door switch and high voltage ones are historical. I think. It says they passed on last test and then there's a "since clear: history"

I think I should probably spring for the All Data subscription. Just trying to decide on length of subscription.

Minimum AllData is 1 year, I think, but price gets discounts with extra time. I was on AllData 1 year and then renewal was double or more than double, IIRC.

The price went up considerably but it sure did improve once I spent time learning about it. The interactive color wiring diagrams help and it is now more vehicle specific. That's good and bad I guess. While we have three GMT900s in the driveway, I have 3 year subscriptions for the Yukon XL and the 2013 Sierra and keep it open all the time, that's how I'm able to help folks on here.

Dave, there are short term subscriptions, like a month, which we often do for other vehicles that are brought over to get fixed and then go home to their owner.

 

[DaveO9]

probably more than 1 poor ground for most of those
I would look at the gm upfitter guide wiring diagrams and find where the grounds are for the backup sensors and start there with a ohm meter. same for the interior lights passenger side.
i assume you meant ebcm? electronic brake control module, you might want to check that the harness is clean no corrosion or water intrusion, inspect the harness for any pinched or chaffed wires.

hvac is likely a actuator not working 100%, sometimes they can error out and still work acceptably, so unless you are getting froze out inside I would leave that one be for now and tackle it later.

you could look online for any tsb's that mention the backup sensors as they usually have pictures and known spots to look. same for interior lights, could be a lamp holder shorting to the body or anything as simple as that

Thanks for the tips. Good reminder to look for TSBs on the specific issues. Found this one: https://static.nhtsa.gov/odi/tsbs/2014/MC-10112024-9999.pdf Seems like it's saying to ignore the B2555 codes for the lighting circuits - I don't have courtesy lights in the door panels. And I'll take your advice to ignore the HVAC code since everything is working fine - for now. And yes, it's EBCM. Where is the harness you mention?

The price went up considerably but it sure did improve once I spent time learning about it. The interactive color wiring diagrams help and it is now more vehicle specific. That's good and bad I guess. While we have three GMT900s in the driveway, I have 3 year subscriptions for the Yukon XL and the 2013 Sierra and keep it open all the time, that's how I'm able to help folks on here.

Dave, there are short term subscriptions, like a month, which we often do for other vehicles that are brought over to get fixed and then go home to their owner.

Thanks, yeah, I saw that there are month long subscriptions available for $20. But I think I'll do a year and see how it works out. It is more money than I was hoping, but still not even comparable to what it would cost to have a shop do electrical diagnosis.

 

[Doubeleive]

Thanks for the tips. Good reminder to look for TSBs on the specific issues. Found this one: https://static.nhtsa.gov/odi/tsbs/2014/MC-10112024-9999.pdf Seems like it's saying to ignore the B2555 codes for the lighting circuits - I don't have courtesy lights in the door panels. And I'll take your advice to ignore the HVAC code since everything is working fine - for now. And yes, it's EBCM. Where is the harness you mention?



Thanks, yeah, I saw that there are month long subscriptions available for $20. But I think I'll do a year and see how it works out. It is more money than I was hoping, but still not even comparable to what it would cost to have a shop do electrical diagnosis.

on the side of the abs module under the truck