Engages limp mode after head gasket change, how to fix?

Hi,

The problem is likely in the wiring. The code indicates a high voltage issue with the throttle actuator control motor. Chances are we have a short to power and the motor is seeing 12v all the time. Also, when this code is set, the PCM puts the vehicle in limp mode to protect the circuits. That is normal for this issue.

If you look below, I attached the diagnostics for the code. Take a look through them and let me know if you are comfortable performing them.

Here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-wiring

Let me know what you find.

Joe

See pics below.

Hi, thanks for the response. I will grab my multimeter and check this out tomorrow in the afternoon, currently close to midnight, and report the results here!

Hello, I disconnected the negative terminal on the battery and ran my test. I specifically ran the test for a short by grounding and then checking resistance on the throttle body connector, I got no change in the multimeter, aka it kept reading 1. Both T6-2 and T6-1 had no change.

I then jumped into the car and checked the ECM connector. This one felt tricky since the image was upside down when viewed from my angle, but I think I checked it correctly and found the black and white wires to check respectively. These wires also had no change (kept reading 1 on my multimeter).

Would the next step be to change out the entire wire? Or to maybe replace the throttle body connector? I moved the wires around on the throttle body connector while testing to see if maybe it was just loose but still had no change in resistance.

Thanks!

Hi,

It could be either. Is the connector in good condition? Can you pierce the wire to see if there is a difference before the connector?

Joe

The connector is in good condition, I pierced it just now and no different before the connector.

Hi,

when you say it stayed at 1, was it at one when not connected? Also, if you had the battery disconnected and checked it as mentioned, you were checking for a short to ground. Was that your goal?

Let me know.

Joe

Hi, yes it stayed at 1, and correct I was checking for a short. Well long story short I figured it out, the fault was a lose ground wire near the top of the engine. (I must have forgotten to fully tighten a bolt holding a ground wire when I was putting the engine back together from the head gasket job).

More detail: I ended up double checking the throttle body connector for both a short and an open thinking I might have done it wrong after watching more YouTube videos. The wires seemed to pass both tests, so then I followed the mechanics recommendation which was to try an OEM throttle body (I had already ordered the part days back but was waiting for it in the mail). The mechanics reasoning was it didn't like the aftermarket part. So, I did that and tried a used OEM part, that didn't work either, the car went immediately into limp mode.

After scratching my head and staring at the engine for about an hour I decided to turn on the car and just wiggle wires and air pipes around to see what would happen. Eventually I noticed the car would shutter, and even turn off, when I moved a group of wires on the right side of the engine, near the throttle body. I finally narrowed it down to a lose ground wire. I tightened it up and the car started up right away with no check engine light, test drove it around and all is good!

Thanks for the help!

Hi,

Thanks for the update. That is an easy thing to miss. However, I'm glad you found the issue.

If you have questions in the future, feel free to come back anytime.

Take care,

Joe