129k2006

Always a wealth of knowledge here so I thought I would cast a line and see what comes back...

I have an 06 (original owner) HHR 2.2 liter automatic with 303,000 miles. On my third engine now but still the original transmission with a few fluid changes on it (like two). I have been noticing the trans shifting late and even slipping between gears in the past week or so. Also it seems like the rpm is not matching speed sometimes like the trans is slipping while moving. I am not totally thrilled about the thought of replacing the transmission but it sounds like that may be inevitable if I want to keep driving it. I put the new motor in myself about a year ago and am still emotionally and physically scarred from it. I do have some CEL on but they are P420 and P455. They have been on for years and I am not worried about them so long as I can get them to stay off long enough to pass emissions.

So any ideas on quick fixes? Or hard fixes? Coming up on 12 years of ownership and feel I have really gotten my money's worth from this car. Just not ready to throw in the towel yet and get another.

Thanks.

Oldblue

I've been working on a fix for the P0420, the dirty catalytic converter issue, look into the oil build up on the throttle body it will be sucked out of the valve cover, I installed an oil separator tank and ran a bottle of cat cleaner , and cleared the code. It hasn't returned in 500 miles.

P0420 DTC Code - Catalyst System Efficiency Below Threshold (Bank 1)


The evap code P0455 can be just a loose wire or gas cap , which should give a DIC warning

https://www.obd-codes.com/p0455


Both of these codes could be the reason the transmission is shifting weird, also check your ground wires to ensure they are clean and tight.

donbrew

Clearing the code does not make an emissions pass in most states, the condition shows in the OBDII scan.

In my state I can get a safety sticker with the CEL on, but the emissions is a plug in test.

Replacing the gas cap should fix the p0455. Or a broken EVAP tube.

129k2006

Thanks for the quick responses. I have the P455 code pretty much narrowed down to a rusted out steel tube from the canister at the rear to the front solenoid. I have already replaced a rusted out fuel line so suspect that. Not to mention i have replaced the vent solenoid in the engine bay and all of the canister components at the gas tank side as well as the gas cap. Still not clearing. P420 has been an issue for years. Several cats (cheap ones) and O2 sensors with no real results. I have been able to keep the CEL light off just long enough to pass emissions. like donbrew said it is a plug in OBD test. Usually third time is the charm for me.

I will double check the grounding as well regarding the transmission.

donbrew

When you clear the codes all of the OBD tests have to start again, which will give you "not ready" readings. Some states allow a few not readies. You would have at least 2 not ready since the EVAP won't run for a long time and the P0420 will be pending.

I had the same problem with P0420, I never did figure it out. A new cat turned it off for a few days. New injectors turned it off for a few days. New O2 sensors didn't do anything, P0420 means the #2 sensor is working right. I am starting to think oldblue is on to something with the oil vapor idea.

Oldblue

I'm waiting till spring to test isolation of the second O2 sensor to stabilize the gases reading.

donbrew

I tried that, don't bother. The fact that it throws the code means it IS working correctly.

One thing I thought about, but never tried, was putting a resistor on the wire.

Oldblue

You tried



With the first drilled out to 1/2 inch hole, and no luck?

donbrew

Yes. Actually when it was on the #2 sensor I saw no discernible difference in the waveform, it stayed steady at .75V I think was the number I had. I did not put it on a scope, so I couldn't check for tiny variations. All of the books I could find said .5V is normal, but nobody I talked to agreed.

If you study up you find that they are intended for the #1 sensor to basically bypass the injector control for more power without a CEL, or some such. Read: poor gas mileage.

They only cost me about $5

Oldblue

In the #1 position the fuel is richer,so lower fuel mileage.
And that is the position for guys who run a straight pipe with no catalytic converter.
On the #2 it is supposed to stabilize the gases following around the O2 sensor, and the rise and fall of temperatures setting off the code.

So far the oil separator tank has kept the code off for the last 500 miles!