service stabilitrak and service traction control at highway speeds

[Jeff L Roberts]

I recently purchased a 2007 Suburban with the 5.3 engine and through a series of unfortunate events I ended up having a shop put a new engine in it. I got the car back and it seems to drive fine but nearly every time I get it up between 60-70 mph on the highway or interstate, the traction control light comes on and the display cycles between "service stabilitrak" and "service traction control". Sometimes the check engine light comes on and sometimes it blinks while the traction control light is on. I have cheap elm based scanner and the codes it shows are a P0300 Random Misfire, a P0325 Knock Sensor, and a P0446 Evap Vent Circuit. The Random Misfire and Evap were showing before the engine was replaced and I am not sure these or the knock sensor have anything to do with the traction control/stabilitrak messages. What little research I have done says it could be a brake light switch, accelerator pedal position sensor, throttle position sensor, or throttle body. Is there any way to further diagnose this problem without just replacing parts till it goes away? Would I get more information related to this with a better scan tool? I would just take it back to the shop, but I suspect the issue doesn't have anything to do with the new engine. It has 190k miles on it with a remanufactured engine with a 100k/3yr warranty on it.

 

[Doubeleive]

I recently purchased a 2007 Suburban with the 5.3 engine and through a series of unfortunate events I ended up having a shop put a new engine in it. I got the car back and it seems to drive fine but nearly every time I get it up between 60-70 mph on the highway or interstate, the traction control light comes on and the display cycles between "service stabilitrak" and "service traction control". Sometimes the check engine light comes on and sometimes it blinks while the traction control light is on. I have cheap elm based scanner and the codes it shows are a P0300 Random Misfire, a P0325 Knock Sensor, and a P0446 Evap Vent Circuit. The Random Misfire and Evap were showing before the engine was replaced and I am not sure these or the knock sensor have anything to do with the traction control/stabilitrak messages. What little research I have done says it could be a brake light switch, accelerator pedal position sensor, throttle position sensor, or throttle body. Is there any way to further diagnose this problem without just replacing parts till it goes away? Would I get more information related to this with a better scan tool? I would just take it back to the shop, but I suspect the issue doesn't have anything to do with the new engine. It has 190k miles on it with a remanufactured engine with a 100k/3yr warranty on it.

define new engine?
the misfire and knocksensor error's are directly related to the engine, if they re-used anything from the old motor or if the new motor was in fact a used motor then you will need to have the knocksensors replaced oem is best, if you used or they used aftermarket or used sensors that would be the cause of that issue, the random misfire would need to be addressed also could be sparkplug, coil pack, spark plug wires, bad injector, bad injector or coil harness, or even a vacuum leak depending the severity it could be a internal engine part also. the evap problem is related to the gas tank/fuel vapor canister or solenoids and would not cause the stabiltrac issue.

who did your motor replacement? who ever did that should have addressed the misfire/knock sensor issue before you taking delivery of the vehicle

 

[wjburken]

There are a lot of things that can cause your stabilitrak and traction control systems to shut-down. Knock Sensor output / failure is one of them. I agree with Wes. I would definitely take the vehicle back to the place that put the motor in and have them address the knock sensor and misfire issues. As was stated already, make sure they put in OEM knock sensors and that the harness is in top-notch condition as well.

 

[Jeff L Roberts]

There were no codes when I picked it up after getting the engine replaced, but they showed up in the last week since picking it up. As far as I know, it is a reman engine. It has a 3yr/100k mile warranty. It was done at a local shop that I have used before. I cleared the codes that were present when I bought it(there was a random misfire and the evap code) but I have not cleared anything since the engine was replaced. From what you are saying I think I will drop it back off at the shop that replaced the engine and see what they say.

 

[Doubeleive]

There were no codes when I picked it up after getting the engine replaced, but they showed up in the last week since picking it up. As far as I know, it is a reman engine. It has a 3yr/100k mile warranty. It was done at a local shop that I have used before. I cleared the codes that were present when I bought it(there was a random misfire and the evap code) but I have not cleared anything since the engine was replaced. From what you are saying I think I will drop it back off at the shop that replaced the engine and see what they say.

yes the misfire and knock sensor's should be addressed by whoever did the motor, the evap issue is different the easiest way to deal with that is to just replace the 2 evap solenoids and vapor canister, that generally resolves the problem leaks in the vacuum line possible but rare. the reason I say it is the easiest is because by the time you spend money to troubleshoot the problem you are already in just as much money to replace the maybe one bad part when you could have just shotgunned it and did all 3 and be trouble free for another decade.