I have a 2016 Jeep compass with 122,000 miles on it. About a month ago I used my remote start one morning and it revved up really high and sat there for a little and RPMs started fluctuating really bad and my check engine light came on along with the electronic throttle control light and traction control light. I read the code and it was p2173 (vacuum leak, high air flow, slow accumulation). I took off the throttle body which is all electronic but I cleaned it real good with carb cleaner cause it was filthy and I put it back on cleared the code and nothing else happened for a month. After that month it happened again with the same code and RPMs were fluctuating and settled down at 1,500 RPMs which they normally settle down to 800-900 RPMs and it went into limp mode all the way back home. The next day I started it and the warning lights were still on but it was running normally so I cleared the code and decided to take it to work to see what would happen. Went to lunch and it all started again. I have no cracks in my hoses and after research it says it could be the intake manifold gasket or a sensor or the throttle body which I cleaned and it was in good condition. Should I check the manifold gasket or could it really be a sensor
Start the engine, and as the engine idles, take that can of carb cleaner and spray short bursts around the intake area of the engine.
If the idle speeds up at anytime, you’ve found the vacuum leak.
Genius. Thank you
Sprayed with carb cleaner all around the intake manifold and hoses and didn’t notice any changes in idle but unfortunately Jeep doesn’t leave a whole lot of wiggle room around the intake in the compass so I can’t get every nook and cranny. Looking at the intake manifold chart on my code reader the manifold pressure fluctuates when the RPMs start to fluctuate up and down looks like a series of triangles and then the code reader also reads that my accelerator pedal is pressed down by 1.5% and typically sits between 2.7-2.9% when the issue is not occurring. Is there any other data I should look at on the charts to find the issue or steer me in a more direct direction. I can see a decent amount of charts on my code reader which it is a FIXD sensor and I’m not sure how accurate they are with the data
For a sudden change to the vacuum system integrity like that, most likely causes are
- vacuum hose has fallen off or split bigtime
- vacuum actuator diaphragm has split (brake booster a likely culprit)
Suggest temporarily clamping off vacuum hose from intake manifold to brake booster, see if that has any effect. Don’t drive like that, only an experiment.
The codes is saying there’s too much air entering the intake manifold, given the throttle position being commanded. That could be caused by other problems than vacuum system leaks, such as the throttle valve isn’t moving to the correct position. Or it could be that the intake manifold pressure isn’t being measured accurately. Does your car use a MAP device? If so, check the electrical connection.