Main IndexAuto Repair Home Search Posts SEARCH
Who's Online WHO'S
Log in LOG

Search Auto Parts

2005 Pontiac Sunfire Trac Off Light/Random Misfirings

  Email This Post

New User

Oct 2, 2011, 9:38 AM

Post #1 of 3 (6437 views)
2005 Pontiac Sunfire Trac Off Light/Random Misfirings Sign In

2005 Pontiac Sunfire

2.0 Engine

136,000 miles

Hello everyone. Ive had a problem with my sunfire for a few months now. This may be a long description, but i thank you for bearing with me.

The problem started about 3 months ago. While driving, I noticed my Trac off light come on and stay on. The car started jerking (rpm's shooting up then dropping), running rough and stalled out at a stop sign. I cleaned up the throttle body with some cleaner and got a code P0122. I reset the codes and the engine ran fine for about a month.

I turned the car on one morning in the rain and the Trac Off light came back on. The transmission acts weird with hard shifting when accelerating. We changed the spark plugs and reset the codes and once again, the car ran fine. I began to notice a correlation between the weather and the car's performance, i.e the Trac Off light came on in the rain and turned off when the car was dry.

Eventually the Trac Off light came back on regardless of the weather. The normal jerking on acceleration, idle surge, rough transmission shifting, and stalling when pulling from a stop light occured. I replaced the TPS and the car ran fine for a week. After the week, once again, the Trac Off light came on. Again, the computer spit out a P0122 code.

Finally, I took it in to a reputable dealer for repairs. They checked for codes, checked the related wiring and connectors, replaced the 02 sensors and replaced the fuel tank pressure sensor. The mechanic said that when he disconnected the harness for the fuel tank pressure sensor, the voltage for the TPS came back. They also found a faulty purge solenoid. They also replaced the downstream oxygen sensor. The mechanic said that the ignition switch should be replaced and said that that also had to do with the Trac Off light.

The Trac Off light and accompanying problems came back before even leaving the dealership. Turning the engine off made the light go off and run better. The next day, it came back on, and remembering what the mechanic said about the ignition switch being a cause, I replaced the ignition switch. I cleared the codes and the car ran fine.

Driving the car a little later in the night, the Trac Off light again appeared and I noticed my rpm's surging as I turned the car's heater on. I turned the car off and decided not to worry anymore that night about it.

The real trouble started this morning. I attempted to start the car and the engine wouldn't turn over. After trying a few times it finally turned over and the engine sounded horrible, like there was no oil in it (oil was changed recently and wasn't low). The Trac Off light was, of course, lit and the check engine light was blinking steadily. I limped my car around a bit and it had a hard time accelerating and it felt like it was going to stall while driving. The car REEKED of gasoline. I ran my code reader on it and got these codes. P0122, P0300 (random misfiring) and P0452.

I know one of the cylinders is misfiring. Is this a result of the ignition switch? And any thoughts on this Trac Off light issue? Many thanks to all who read and can shed some light on this situation.

Ultimate Carjunky / Moderator
Discretesignals profile image

Oct 3, 2011, 7:45 PM

Post #2 of 3 (6392 views)
Re: 2005 Pontiac Sunfire Trac Off Light/Random Misfirings Sign In

Check engine light is blinking because you have a catalyst damaging misfire going on. The trac light is on because the misfiring or the TPS problem the PCM is picking up on is causing the PCM to tell the EBTCM to disable the traction control and turn the trac off light on.

You need to figure out which cylinders are missing. A high end scan tool can view misfire data which enables you to look at misfire current and history to see which cylinders are missing. Once you determine which cylinders are missing, you need to determine why. The misfire is the result of an ignition, fuel, or mechanical issue. Once you narrow down which one of systems is the cause, then you need to narrow down the culprit in that system.

Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

New User

Oct 5, 2011, 7:00 PM

Post #3 of 3 (6381 views)
Re: 2005 Pontiac Sunfire Trac Off Light/Random Misfirings Sign In

Thank you for your response.

Ive taken it back to the dealership and they tell me that I need to have the ignition module, the ignition coil pack, the boots, and the spark plugs replaced. They say that two of the four cylinders were not firing at all. The mechanic assures me this will fix the problem. I hope he is right.

  Email This Post

Feed Button

Search for (options) Privacy Sitemap

site analytics