# Throttle body gremlins



## lotusuzu1991 (Jan 15, 2022)

Hi everyone,
I'm the owner of a 2013 Sonic 1.4 that was bought new. It has been problem free until about 90,000 miles, when the check valve in the intake manifold failed and the coolant hose on the transmission side of the motor started leaking coolant on everything. I replaced the intake manifold with a new one, and the drivability returned to normal. Within 2000 miles I began to experience severe loss of power (I would actually have a _little_ more power with the air conditioning ON), and so I began to go through this forum to find some answers. Fast forward several months, and I have replaced the following with new factory replacements: MAF sensor, MAP sensor, turbo assembly, intake manifold, throttle body, accelerator pedal position sensor, and the boost pressure sensors. I did not blindly replace all of these - I scanned the codes as I went and addressed them accordingly. The turbine was sticking a bit and the wastegate flap was not sitting flush, so there was a good leak. The boost sensor underneath the intake manifold was cracked at the nipple, leaking air. The MAF for whatever reason had a clear oily substance leaking from it (I only use a regular paper filter, so this one confused the hell out of me to see this). Funny thing though, each time I replaced parts new codes would pop up. I have also performed a leak check on the engine, and it is leak free. I am currently at this point: when I turn on the car it idles normally and does not exhibit any codes, although when I go to drive it it has so little power it'll actually stall as I'm letting off the clutch. I decided to film the action of the throttle body with the intercooler hose removed because I suspected the throttle body still was not working properly. When I turn on the ignition (not the engine) and press the accelerator pedal, the throttle body opens maybe 30% of the way, then back to idle position, with no position in between. It's like on/off. I tested the connections in the pigtail connector, and they're fine. I am completely at a loss at this point.
I am close to losing my job because I don't have other transportation and I can't afford to keep taking an Uber 40 miles every day, let alone more replacement parts, so I hope to goodness someone here might know what is going on. Please help!


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## lotusuzu1991 (Jan 15, 2022)

Additional notes: the brake booster pump attached to the intake manifold whirrs on every 5 seconds. I've been searching on all sorts of forums and it appears that the only code I'm getting now (P0068) can be caused by a defective brake booster pump. So I've disconnected that hose from the intake manifold and covered the nipple on the manifold with a rubber cap and tried to drive the car (after removing the battery leads, touching them together for 10 seconds [old VW trick that worked for me] and reattaching them), but still the insane lack of power persists. Is it possible the ECU is still reading this leak and causing the code to pop up even though the hose is disconnected?

I feel that a lot of Cruze/Sonic/Trax owners with this phantom issue would benefit, so let's get some ideas flowing!


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## BadBowtie (Apr 18, 2015)

I have to ask the obvious question,.. sorry.
Have you replaced the Spark Plugs and Air Filter recently?

Check FORUM for "Hesitation Gone" and "PCV system Explained" also.
Hope that helps.


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## lotusuzu1991 (Jan 15, 2022)

^ indeed so. Spark plugs and air filter were changed about 3000 miles ago. Also, it's definitely not related to the PCV system since a smoke check showed no leaks from the engine.

Ive had a thought - I tried driving it today since there's little traffic on the country road I live on, and what happened was the car died on me in less than a quarter mile and would not restart. This is with a new battery less than 5 months old. I jump started it and drove back home, and it died again in my driveway. Now, since some of the codes were related to the MAP sensor, MAF sensor, and throttle position sensor, and each of those components require specific voltage, is it possible the alternator is causing this lack of drivability? The car should have been able to restart no matter what, but all I got was the famous clickclickclickclick of a dead battery, and jumpstarting it got it going. A failing alternator won't produce the necessary 12v to keep the engine running, so this is how this thought popped into my head.

I just wanted to see what you all think before I go spending more money I don't really have anymore on a new alternator...


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## lotusuzu1991 (Jan 15, 2022)

Battery tests at 12.7v, and alternator tests at 15.3v when running. I examined the fuse block on the positive battery terminal, and two of them were covered in green corrosion. I was unable to find the meaning of the fuses (IEC, REC, UEC), so is it possible that these could be a culprit as well? I understand the Cruze fuse block is different, but maybe someone has some insight?


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## Coreyg06 (10 mo ago)

I know its been a few month but Man I've been in almost the exact same situation as you since I got the car and it bent a valve 50 miles after I got it. I pulled the head and changed the valves and all gaskets, taking Uber back and forth which is 40 each way for me. I bought a new ecm and nothing changed so I returned it. I get different codes evertime i replace something due to codes or just preventative maintenance. What I found is a bunch of bent pins on x1,2 , and 3 on the bottom of the fuse block so maybe check there. I also found my plugs weren't properly seating on the ecm. And some corrosion on one of the comps behind the driver side kick panel by the trunk release. I finally got everything repaired and now it starts again finally but it's in limp mode with Trac control. I wish I had more insight for you but if u haven't done it, upgrade the grounds and power to the alternator i would and also do the pcv repair kit to eliminate future issues if u haven't already. I've checked resistance on every single wire on the car I can find and they're good, including from ecm to bcm .These cars have the worst electrical I've ever experienced on a vehicle, and chevy def dropped the ball on it. For me I'm going to get a new throttle body later because apparently thats the only "fix" I can find on multiple websites, maybe it'll work maybe not, but we'll see. Also the CT around the negative regulates voltage depending on the draw the vehicle is requiring. This and other forums says 15+ vdc is fine but in my experience with other cars it's not. Maybe these cars different from every other vehicle, idk. But ive gone through everything on this car and read at least 50+ hours on forums. If the throttle body fixes it, I'm selling it tomorrow for whatever I can get because I've spent over 150 hrs going through everything. I know it's a long post lol but if your still here amazon has a dorman for 100$ if u can afford to wait a day or 2. Hopefully some info I gave can help u, if not lmk and ill see if I can figure something out


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## lotusuzu1991 (Jan 15, 2022)

Thank you for your reply Corey. I ended up buying a $200 car down the road from me while I work on this mess. I broke my foot in April so everything's been slow-going. I upgraded all the ground wires underneath the battery, but I haven't checked anything under the carpet by the driver's kick panel. Come to think of it, considering how much salt I can see coming through the carpet, there might be an issue there. I'm going to check it out and see what I find. 
Did you have any luck with the replacement throttle body?


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