Hello Sonic Friends,
TLDR: My 2014 Sonic is intermittently throwing both P0299 and P0234 - turbo overboost and underboost condition.
I need some help troubleshooting a longstanding issue with my 2014 Sonic. I appreciate any suggestions or pointers.
My Sonic has about 150,000 miles on the odometer. I replaced my turbocharger with an aftermarket turbo at about 120,000 miles - the stock part failed. When I first had this professionally installed by a mechanic, the check engine light came on with P0299 (turbo underboost condition). The mechanic fixed this by tightening the rod controlling the wastegate. For nearly a year, I had no issues.
For the past three months, I've been getting a P0234 code (overboost condition). My mechanic replaced the boost sensor, which didn't solve the issue. He then tried adjusting the wastegate rod slightly. This worked for maybe a couple of weeks. Now my Sonic is intermittently throwing both P0299 and P0234 together.
I've only noticed two changes in my car's performance. Occasionally, the engine has a hard time accelerating from 0 to about 45. The revs get up to 5,0000+ and stay there, until it finally shifts. This doesn't feel like a transmission issue, but rather a significant loss of engine power. Secondly, I've noticed a dramatic drop in MPG.
For further context, at about 120,000 miles, my engine threw a p0420 code. I tried to clean out my catalytic convertor to fix the emissions issue, but the code still threw. Because of this, I bypassed the 02 sensor to keep the check engine light off. I was formerly living in California, where compliant convertors are staggeringly expensive.
Please let me know if you have any ideas or suggestions. I have worked extensively on vehicles and don't always rely on mechanics. I've replaced my Sonic's radiator, hoses, and many other parts when I was getting the notorious overheating issues.
Thank you so much.
TLDR: My 2014 Sonic is intermittently throwing both P0299 and P0234 - turbo overboost and underboost condition.
I need some help troubleshooting a longstanding issue with my 2014 Sonic. I appreciate any suggestions or pointers.
My Sonic has about 150,000 miles on the odometer. I replaced my turbocharger with an aftermarket turbo at about 120,000 miles - the stock part failed. When I first had this professionally installed by a mechanic, the check engine light came on with P0299 (turbo underboost condition). The mechanic fixed this by tightening the rod controlling the wastegate. For nearly a year, I had no issues.
For the past three months, I've been getting a P0234 code (overboost condition). My mechanic replaced the boost sensor, which didn't solve the issue. He then tried adjusting the wastegate rod slightly. This worked for maybe a couple of weeks. Now my Sonic is intermittently throwing both P0299 and P0234 together.
I've only noticed two changes in my car's performance. Occasionally, the engine has a hard time accelerating from 0 to about 45. The revs get up to 5,0000+ and stay there, until it finally shifts. This doesn't feel like a transmission issue, but rather a significant loss of engine power. Secondly, I've noticed a dramatic drop in MPG.
For further context, at about 120,000 miles, my engine threw a p0420 code. I tried to clean out my catalytic convertor to fix the emissions issue, but the code still threw. Because of this, I bypassed the 02 sensor to keep the check engine light off. I was formerly living in California, where compliant convertors are staggeringly expensive.
Please let me know if you have any ideas or suggestions. I have worked extensively on vehicles and don't always rely on mechanics. I've replaced my Sonic's radiator, hoses, and many other parts when I was getting the notorious overheating issues.
Thank you so much.
