Traction control/stabilitrak off issue **Update: Solved, see 1st post edit**
The other day when driving back to work from Home Depot, the traction control off/service stabilitrak lights lit up on the Tahoe. I pulled into the gas station, filled up, and hoped it was a fluke. Upon going to restart the truck, it was running REALLY rough. It barely started. Got it home after work, popped the hood, and low and behold the intake tube had popped loose from the throttle body (airraid tube). Disconnected the neg terminal, reattached the tube nice and tight, and let it sit overnight to make sure the code cleared out.
The next morning it fired right up, and off to work I went. Lunchtime rolls around and the damn stabilitrak warning came back on! It was intermittent, it came on only as I was coasting or sitting at a red light. Checked the tube, it was rock solid. Eventually it threw a CEL, so I stopped by the auto parts store after work to read the code. Banks 1 and 2 too rich. WTF?
I got home and disco'd the battery again, pulled the intake, checked all the fittings, gave the MAF sensor a good cleaning, and carefully reassembled everything. It lasted about a half a day before starting to act wonky again. Same thing is still going on. CEL with the same codes, and intermittent service stabilitrak/traction control off lights (with the resulting super-hard shift out of first gear) when coasting or sitting at a red light, then after accelerating and getting out of first gear it usually goes off and acts normally until I start slowing down again.
I'm at a loss. The intake doesn't appear to be cracked or damaged anywhere. Most of the time the truck starts up fine, but on occasion it struggles ever so slightly. Nothing like when the tube was off, but just a hair off of normal. Once it's running it seems normal. There has to be an intake/vacuum leak somewhere, but I have no idea where. Any suggestions?
-----UPDATE 12/31/2013: Issue Solved-----
Ok, so rather than making everyone read through the entire thread, I'll post the resolution here for everyone's edification.
This issue was 100% caused by the Airaid intake tube coming loose. When that happened, the engine was drawing air directly into the throttle body, completely bypassing the Mass Air Flow sensor. As a result, the ECM thought that the Air/Fuel Ratio was EXTREMELY leaned out because there was so much un-metered air coming into the engine. So, naturally, the computer started dumping fuel to "correct" what it assumed to be a lean fuel condition, which made the AFR super rich (hence the P0172 and P0175 codes, "banks 1 and 2 too rich"). When the injectors were maxed out and the problem still wasn't solved, the computer then assumed that there was E85 in the tank, and the flex fuel system activated the E85 fuel tables (obviously there wasn't E85 in the tank - not good). This left the injectors maxed out, which kept the AFR way too rich, and caused the rough starts and random stabilitrak/traction control issues because at idle, the computer was looking for E85 when gasoline was in the tank.
Essentially, the computer was extremely f**king confused. Eventually, my truck wouldn't even start because it was flooding itself with so much fuel during startup.
Rather than waiting for a scan cable to arrive, I just bit the bullet and ordered my own AutoCal. After receiving it, I simply hooked it up to my truck, connected my laptop and opened up the EFI Live software, and did an Ethanol % Correction. This zeroed out the fuel tables and allowed the computer to recognize the regular gasoline as gasoline, and not E85. Its been three days since the reset, and not a single issue has persisted.
I don't know if this issue would require a dealership re-flash of the stock computer if you aren't tuned and don't have access to EFI Live, but it's worth noting that if you have an aftermarket intake on a GMT900 truck, MAKE SURE that it's very tightly installed. If you have any questions about this, feel free to PM me. Thanks for reading!
The other day when driving back to work from Home Depot, the traction control off/service stabilitrak lights lit up on the Tahoe. I pulled into the gas station, filled up, and hoped it was a fluke. Upon going to restart the truck, it was running REALLY rough. It barely started. Got it home after work, popped the hood, and low and behold the intake tube had popped loose from the throttle body (airraid tube). Disconnected the neg terminal, reattached the tube nice and tight, and let it sit overnight to make sure the code cleared out.
The next morning it fired right up, and off to work I went. Lunchtime rolls around and the damn stabilitrak warning came back on! It was intermittent, it came on only as I was coasting or sitting at a red light. Checked the tube, it was rock solid. Eventually it threw a CEL, so I stopped by the auto parts store after work to read the code. Banks 1 and 2 too rich. WTF?
I got home and disco'd the battery again, pulled the intake, checked all the fittings, gave the MAF sensor a good cleaning, and carefully reassembled everything. It lasted about a half a day before starting to act wonky again. Same thing is still going on. CEL with the same codes, and intermittent service stabilitrak/traction control off lights (with the resulting super-hard shift out of first gear) when coasting or sitting at a red light, then after accelerating and getting out of first gear it usually goes off and acts normally until I start slowing down again.
I'm at a loss. The intake doesn't appear to be cracked or damaged anywhere. Most of the time the truck starts up fine, but on occasion it struggles ever so slightly. Nothing like when the tube was off, but just a hair off of normal. Once it's running it seems normal. There has to be an intake/vacuum leak somewhere, but I have no idea where. Any suggestions?
-----UPDATE 12/31/2013: Issue Solved-----
Ok, so rather than making everyone read through the entire thread, I'll post the resolution here for everyone's edification.
This issue was 100% caused by the Airaid intake tube coming loose. When that happened, the engine was drawing air directly into the throttle body, completely bypassing the Mass Air Flow sensor. As a result, the ECM thought that the Air/Fuel Ratio was EXTREMELY leaned out because there was so much un-metered air coming into the engine. So, naturally, the computer started dumping fuel to "correct" what it assumed to be a lean fuel condition, which made the AFR super rich (hence the P0172 and P0175 codes, "banks 1 and 2 too rich"). When the injectors were maxed out and the problem still wasn't solved, the computer then assumed that there was E85 in the tank, and the flex fuel system activated the E85 fuel tables (obviously there wasn't E85 in the tank - not good). This left the injectors maxed out, which kept the AFR way too rich, and caused the rough starts and random stabilitrak/traction control issues because at idle, the computer was looking for E85 when gasoline was in the tank.
Essentially, the computer was extremely f**king confused. Eventually, my truck wouldn't even start because it was flooding itself with so much fuel during startup.
Rather than waiting for a scan cable to arrive, I just bit the bullet and ordered my own AutoCal. After receiving it, I simply hooked it up to my truck, connected my laptop and opened up the EFI Live software, and did an Ethanol % Correction. This zeroed out the fuel tables and allowed the computer to recognize the regular gasoline as gasoline, and not E85. Its been three days since the reset, and not a single issue has persisted.
I don't know if this issue would require a dealership re-flash of the stock computer if you aren't tuned and don't have access to EFI Live, but it's worth noting that if you have an aftermarket intake on a GMT900 truck, MAKE SURE that it's very tightly installed. If you have any questions about this, feel free to PM me. Thanks for reading!
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