Codes P0BBD and P0AC4
#1
09-25-2017, 06:53 PM
Join Date: May 2010
Location: Paradise Valley Arizona
Posts: 112
Codes P0BBD and P0AC4
So my yellow check engine light came on today, no visible drive ability issues, Hybrid System seems to be functioning properly, auto-stop, Etc.
Get home pull the codes and I get P0BBD & P0AC4...cool, no problem, I know these codes P0BBD = "Hybrid Battery Pack Voltage Variation Exceeded" (usually one or more dead cells) , P0AC4 is just a generic code for the Hybrid module telling the Engine module to turn on the yellow check engine light (triggered by the other code).
I knew this day was coming and have been mentally prepared, my Tahoe is nearly 9 years old with 165K miles and the Traction Battery doesn't last forever, I knew cells will need to be replaced.
I remove & disassemble the traction Battery intending to figure out how many cells are bad and how many I should order(usually on these batteries it's 2 or 4 cells, they never seem to go bad in singles)...only one problem, they all check out excellent, all 40 cells are 7.81-7.92 volts? The battery is clean, I didn't see anything amiss.
Obviously the codes were cleared, I put it back together the computer relearned the driving cycle and everything seems fine now? no light, no codes.
I'm going to just monitor it unless anyone has any insight. At least I know exactly how to disassemble the traction battery when that time does come.
Get home pull the codes and I get P0BBD & P0AC4...cool, no problem, I know these codes P0BBD = "Hybrid Battery Pack Voltage Variation Exceeded" (usually one or more dead cells) , P0AC4 is just a generic code for the Hybrid module telling the Engine module to turn on the yellow check engine light (triggered by the other code).
I knew this day was coming and have been mentally prepared, my Tahoe is nearly 9 years old with 165K miles and the Traction Battery doesn't last forever, I knew cells will need to be replaced.
I remove & disassemble the traction Battery intending to figure out how many cells are bad and how many I should order(usually on these batteries it's 2 or 4 cells, they never seem to go bad in singles)...only one problem, they all check out excellent, all 40 cells are 7.81-7.92 volts? The battery is clean, I didn't see anything amiss.
Obviously the codes were cleared, I put it back together the computer relearned the driving cycle and everything seems fine now? no light, no codes.
I'm going to just monitor it unless anyone has any insight. At least I know exactly how to disassemble the traction battery when that time does come.
#2
09-25-2017, 07:32 PM
Re: Codes P0BBD and P0AC4
Hey neighbor.
- Resting voltage tells you almost nothing about a module being good or bad. It generally confirms bad when it is below nominal, but horrible, horrible garbage modules can have a "perfect" resting voltage.
- Resting voltages of healhty/balanced modules should be extremely close to one another. Anything outside a .05V range below max is HIGHLY suspect. Anything outside a 0.3V range below max is probably suspect. If your max is an outlier, it could be the problem, AND there are sometimes some exceptions for the end modules in cooler climates than AZ - they might be .07V low and still be acceptable. 0.11V deviation is resting voltages is a mile.
- Resting voltages should also be measured after at least 10 hours and preferably 24 hours after last charge/discharge operation of any kind..
- The next time you pull it apart (likely soon), get a 100A/12V load tester and hit each module for 15 seconds - record loaded voltage at the 15 second mark on a separately attached voltmeter.
You will likely see substantial variation in those loaded voltages - which gives a lot of insight into overall health but no specifics. Anything outside a 0.15V variation is marginal. Anything outside a 0.2V variation is likely junk.
Did you tighten all the nuts to 48 in-lb? This is pretty important. Too much more, and you'll break the studs off, too much less, and you get high resistance.
Did you clean the bus bars? Generally, corrosion is a non-issue here in AZ, but it never hurts. The only part that matters is the circular portion in contact with the terminal end.
A module is good if:
1) it has an acceptable capacity.
2) it has acceptable internal resistance.
3) it has acceptable self-discharge.
resting voltage tells you none of the above.
loaded voltage gives you a number that is influenced by the above, i.e., modules that have a loaded voltage of within 0.15V likely have compatible capacity, internal resistance and self discharge (if test is done at least 24 hours after last charge/discharge - 7 days preferable).
You may poo-poo the idea that 0.11V is a mile in terms of voltage. Consider that since you can't measure the cells, you can't tell what they are doing. A 0.01V deviation in CELL voltages will have a substantial impact on capacity, e.g., two cells of identical capacity; 1 has 1.27V resting voltage and the other has 1.26V resting voltage - they will have about 10-20% different capacity. These numbers are illustrative and based on recollection of results, not absolutes.
It's the weakest cell in a module that determines the capacity (and performance) of a module. If your 7.81V module is lower than your 7.92V module because of two cells are 0.05V each lower than the other 4, then they will dictate the performance of the module and will underperform by a large margin.
Good luck,
Steve
- Resting voltage tells you almost nothing about a module being good or bad. It generally confirms bad when it is below nominal, but horrible, horrible garbage modules can have a "perfect" resting voltage.
- Resting voltages of healhty/balanced modules should be extremely close to one another. Anything outside a .05V range below max is HIGHLY suspect. Anything outside a 0.3V range below max is probably suspect. If your max is an outlier, it could be the problem, AND there are sometimes some exceptions for the end modules in cooler climates than AZ - they might be .07V low and still be acceptable. 0.11V deviation is resting voltages is a mile.
- Resting voltages should also be measured after at least 10 hours and preferably 24 hours after last charge/discharge operation of any kind..
- The next time you pull it apart (likely soon), get a 100A/12V load tester and hit each module for 15 seconds - record loaded voltage at the 15 second mark on a separately attached voltmeter.
You will likely see substantial variation in those loaded voltages - which gives a lot of insight into overall health but no specifics. Anything outside a 0.15V variation is marginal. Anything outside a 0.2V variation is likely junk.
Did you tighten all the nuts to 48 in-lb? This is pretty important. Too much more, and you'll break the studs off, too much less, and you get high resistance.
Did you clean the bus bars? Generally, corrosion is a non-issue here in AZ, but it never hurts. The only part that matters is the circular portion in contact with the terminal end.
A module is good if:
1) it has an acceptable capacity.
2) it has acceptable internal resistance.
3) it has acceptable self-discharge.
resting voltage tells you none of the above.
loaded voltage gives you a number that is influenced by the above, i.e., modules that have a loaded voltage of within 0.15V likely have compatible capacity, internal resistance and self discharge (if test is done at least 24 hours after last charge/discharge - 7 days preferable).
You may poo-poo the idea that 0.11V is a mile in terms of voltage. Consider that since you can't measure the cells, you can't tell what they are doing. A 0.01V deviation in CELL voltages will have a substantial impact on capacity, e.g., two cells of identical capacity; 1 has 1.27V resting voltage and the other has 1.26V resting voltage - they will have about 10-20% different capacity. These numbers are illustrative and based on recollection of results, not absolutes.
It's the weakest cell in a module that determines the capacity (and performance) of a module. If your 7.81V module is lower than your 7.92V module because of two cells are 0.05V each lower than the other 4, then they will dictate the performance of the module and will underperform by a large margin.
Good luck,
Steve
#3
09-25-2017, 08:10 PM
Join Date: May 2010
Location: Paradise Valley Arizona
Posts: 112
Re: Codes P0BBD and P0AC4
Hey neighbor.
- Resting voltage tells you almost nothing about a module being good or bad. It generally confirms bad when it is below nominal, but horrible, horrible garbage modules can have a "perfect" resting voltage.
- Resting voltages of healhty/balanced modules should be extremely close to one another. Anything outside a .05V range below max is HIGHLY suspect. Anything outside a 0.3V range below max is probably suspect. If your max is an outlier, it could be the problem, AND there are sometimes some exceptions for the end modules in cooler climates than AZ - they might be .07V low and still be acceptable. 0.11V deviation is resting voltages is a mile.
- Resting voltages should also be measured after at least 10 hours and preferably 24 hours after last charge/discharge operation of any kind..
- The next time you pull it apart (likely soon), get a 100A/12V load tester and hit each module for 15 seconds - record loaded voltage at the 15 second mark on a separately attached voltmeter.
You will likely see substantial variation in those loaded voltages - which gives a lot of insight into overall health but no specifics. Anything outside a 0.15V variation is marginal. Anything outside a 0.2V variation is likely junk.
Did you tighten all the nuts to 48 in-lb? This is pretty important. Too much more, and you'll break the studs off, too much less, and you get high resistance.
Did you clean the bus bars? Generally, corrosion is a non-issue here in AZ, but it never hurts. The only part that matters is the circular portion in contact with the terminal end.
A module is good if:
1) it has an acceptable capacity.
2) it has acceptable internal resistance.
3) it has acceptable self-discharge.
resting voltage tells you none of the above.
loaded voltage gives you a number that is influenced by the above, i.e., modules that have a loaded voltage of within 0.15V likely have compatible capacity, internal resistance and self discharge (if test is done at least 24 hours after last charge/discharge - 7 days preferable).
You may poo-poo the idea that 0.11V is a mile in terms of voltage. Consider that since you can't measure the cells, you can't tell what they are doing. A 0.01V deviation in CELL voltages will have a substantial impact on capacity, e.g., two cells of identical capacity; 1 has 1.27V resting voltage and the other has 1.26V resting voltage - they will have about 10-20% different capacity. These numbers are illustrative and based on recollection of results, not absolutes.
It's the weakest cell in a module that determines the capacity (and performance) of a module. If your 7.81V module is lower than your 7.92V module because of two cells are 0.05V each lower than the other 4, then they will dictate the performance of the module and will underperform by a large margin.
Good luck,
Steve
- Resting voltage tells you almost nothing about a module being good or bad. It generally confirms bad when it is below nominal, but horrible, horrible garbage modules can have a "perfect" resting voltage.
- Resting voltages of healhty/balanced modules should be extremely close to one another. Anything outside a .05V range below max is HIGHLY suspect. Anything outside a 0.3V range below max is probably suspect. If your max is an outlier, it could be the problem, AND there are sometimes some exceptions for the end modules in cooler climates than AZ - they might be .07V low and still be acceptable. 0.11V deviation is resting voltages is a mile.
- Resting voltages should also be measured after at least 10 hours and preferably 24 hours after last charge/discharge operation of any kind..
- The next time you pull it apart (likely soon), get a 100A/12V load tester and hit each module for 15 seconds - record loaded voltage at the 15 second mark on a separately attached voltmeter.
You will likely see substantial variation in those loaded voltages - which gives a lot of insight into overall health but no specifics. Anything outside a 0.15V variation is marginal. Anything outside a 0.2V variation is likely junk.
Did you tighten all the nuts to 48 in-lb? This is pretty important. Too much more, and you'll break the studs off, too much less, and you get high resistance.
Did you clean the bus bars? Generally, corrosion is a non-issue here in AZ, but it never hurts. The only part that matters is the circular portion in contact with the terminal end.
A module is good if:
1) it has an acceptable capacity.
2) it has acceptable internal resistance.
3) it has acceptable self-discharge.
resting voltage tells you none of the above.
loaded voltage gives you a number that is influenced by the above, i.e., modules that have a loaded voltage of within 0.15V likely have compatible capacity, internal resistance and self discharge (if test is done at least 24 hours after last charge/discharge - 7 days preferable).
You may poo-poo the idea that 0.11V is a mile in terms of voltage. Consider that since you can't measure the cells, you can't tell what they are doing. A 0.01V deviation in CELL voltages will have a substantial impact on capacity, e.g., two cells of identical capacity; 1 has 1.27V resting voltage and the other has 1.26V resting voltage - they will have about 10-20% different capacity. These numbers are illustrative and based on recollection of results, not absolutes.
It's the weakest cell in a module that determines the capacity (and performance) of a module. If your 7.81V module is lower than your 7.92V module because of two cells are 0.05V each lower than the other 4, then they will dictate the performance of the module and will underperform by a large margin.
Good luck,
Steve
I was told that the P0BBD code would trigger under greater than 1.5 volts difference between any cells under resting condition(but I don't exactly trust the dealer mechanics advice when it comes to Hybrid Tahoes), I figured there were other codes for the battery for different circumstances.
The light hasn't come back on but it will...that's inevitable, Traction batteries don't last forever.
If a reputable source sold a reasonably priced NEW(not refurbished) replacement battery I would consider that route, the current prices and the difficulty in actually getting one make it a no go for me. I can replace a lot of cells for the price of a new battery.
#4
09-25-2017, 08:53 PM
Join Date: May 2010
Location: Paradise Valley Arizona
Posts: 112
Re: Codes P0BBD and P0AC4
Hey neighbor.
- Resting voltage tells you almost nothing about a module being good or bad. It generally confirms bad when it is below nominal, but horrible, horrible garbage modules can have a "perfect" resting voltage.
- Resting voltages of healhty/balanced modules should be extremely close to one another. Anything outside a .05V range below max is HIGHLY suspect. Anything outside a 0.3V range below max is probably suspect. If your max is an outlier, it could be the problem, AND there are sometimes some exceptions for the end modules in cooler climates than AZ - they might be .07V low and still be acceptable. 0.11V deviation is resting voltages is a mile.
- Resting voltages should also be measured after at least 10 hours and preferably 24 hours after last charge/discharge operation of any kind..
- The next time you pull it apart (likely soon), get a 100A/12V load tester and hit each module for 15 seconds - record loaded voltage at the 15 second mark on a separately attached voltmeter.
You will likely see substantial variation in those loaded voltages - which gives a lot of insight into overall health but no specifics. Anything outside a 0.15V variation is marginal. Anything outside a 0.2V variation is likely junk.
Did you tighten all the nuts to 48 in-lb? This is pretty important. Too much more, and you'll break the studs off, too much less, and you get high resistance.
Did you clean the bus bars? Generally, corrosion is a non-issue here in AZ, but it never hurts. The only part that matters is the circular portion in contact with the terminal end.
A module is good if:
1) it has an acceptable capacity.
2) it has acceptable internal resistance.
3) it has acceptable self-discharge.
resting voltage tells you none of the above.
loaded voltage gives you a number that is influenced by the above, i.e., modules that have a loaded voltage of within 0.15V likely have compatible capacity, internal resistance and self discharge (if test is done at least 24 hours after last charge/discharge - 7 days preferable).
You may poo-poo the idea that 0.11V is a mile in terms of voltage. Consider that since you can't measure the cells, you can't tell what they are doing. A 0.01V deviation in CELL voltages will have a substantial impact on capacity, e.g., two cells of identical capacity; 1 has 1.27V resting voltage and the other has 1.26V resting voltage - they will have about 10-20% different capacity. These numbers are illustrative and based on recollection of results, not absolutes.
It's the weakest cell in a module that determines the capacity (and performance) of a module. If your 7.81V module is lower than your 7.92V module because of two cells are 0.05V each lower than the other 4, then they will dictate the performance of the module and will underperform by a large margin.
Good luck,
Steve
- Resting voltage tells you almost nothing about a module being good or bad. It generally confirms bad when it is below nominal, but horrible, horrible garbage modules can have a "perfect" resting voltage.
- Resting voltages of healhty/balanced modules should be extremely close to one another. Anything outside a .05V range below max is HIGHLY suspect. Anything outside a 0.3V range below max is probably suspect. If your max is an outlier, it could be the problem, AND there are sometimes some exceptions for the end modules in cooler climates than AZ - they might be .07V low and still be acceptable. 0.11V deviation is resting voltages is a mile.
- Resting voltages should also be measured after at least 10 hours and preferably 24 hours after last charge/discharge operation of any kind..
- The next time you pull it apart (likely soon), get a 100A/12V load tester and hit each module for 15 seconds - record loaded voltage at the 15 second mark on a separately attached voltmeter.
You will likely see substantial variation in those loaded voltages - which gives a lot of insight into overall health but no specifics. Anything outside a 0.15V variation is marginal. Anything outside a 0.2V variation is likely junk.
Did you tighten all the nuts to 48 in-lb? This is pretty important. Too much more, and you'll break the studs off, too much less, and you get high resistance.
Did you clean the bus bars? Generally, corrosion is a non-issue here in AZ, but it never hurts. The only part that matters is the circular portion in contact with the terminal end.
A module is good if:
1) it has an acceptable capacity.
2) it has acceptable internal resistance.
3) it has acceptable self-discharge.
resting voltage tells you none of the above.
loaded voltage gives you a number that is influenced by the above, i.e., modules that have a loaded voltage of within 0.15V likely have compatible capacity, internal resistance and self discharge (if test is done at least 24 hours after last charge/discharge - 7 days preferable).
You may poo-poo the idea that 0.11V is a mile in terms of voltage. Consider that since you can't measure the cells, you can't tell what they are doing. A 0.01V deviation in CELL voltages will have a substantial impact on capacity, e.g., two cells of identical capacity; 1 has 1.27V resting voltage and the other has 1.26V resting voltage - they will have about 10-20% different capacity. These numbers are illustrative and based on recollection of results, not absolutes.
It's the weakest cell in a module that determines the capacity (and performance) of a module. If your 7.81V module is lower than your 7.92V module because of two cells are 0.05V each lower than the other 4, then they will dictate the performance of the module and will underperform by a large margin.
Good luck,
Steve
#5
09-25-2017, 09:44 PM
Re: Codes P0BBD and P0AC4
Good information, Thanks.
I was told that the P0BBD code would trigger under greater than 1.5 volts difference between any cells under resting condition(but I don't exactly trust the dealer mechanics advice when it comes to Hybrid Tahoes), I figured there were other codes for the battery for different circumstances.
The light hasn't come back on but it will...that's inevitable, Traction batteries don't last forever.
If a reputable source sold a reasonably priced NEW(not refurbished) replacement battery I would consider that route, the current prices and the difficulty in actually getting one make it a no go for me. I can replace a lot of cells for the price of a new battery.
I was told that the P0BBD code would trigger under greater than 1.5 volts difference between any cells under resting condition(but I don't exactly trust the dealer mechanics advice when it comes to Hybrid Tahoes), I figured there were other codes for the battery for different circumstances.
The light hasn't come back on but it will...that's inevitable, Traction batteries don't last forever.
If a reputable source sold a reasonably priced NEW(not refurbished) replacement battery I would consider that route, the current prices and the difficulty in actually getting one make it a no go for me. I can replace a lot of cells for the price of a new battery.
When you go to load test a module, it helps to affix 2 bus bars on the terminal and clamp as follows:
#7
04-07-2020, 03:25 PM
Re: Codes P0BBD and P0AC4
Hey to just just jump into this thread but I have the same codes on my Escalade but the cel comes and goes what would I have to check to make sure the battery pack isn’t bad
#8
04-07-2020, 03:48 PM
Re: Codes P0BBD and P0AC4
It's definitely bad. It's just a matter of WHEN you'll have to replace it (soon), not if.
Here are test results for a 2011 Silverado with only 57K on it:
https://www.greenhybrid.com/forums/f...iles-p0-32286/
Here are test results for a 2011 Silverado with only 57K on it:
https://www.greenhybrid.com/forums/f...iles-p0-32286/
#9
04-07-2020, 04:02 PM
Re: Codes P0BBD and P0AC4
Sigh thanks hope so can get atleast a year before trying to replace it so I can save up and replace it and another thing will it hurt to drive with a bad battery pack for sometime
