I've only had my Ion about a month and have had nothing but problems. The check engine light comes on everytime I hit 3/4 tank and shortly after, reduced power light illuminates. My mechanic has scanned and replaced something weekly. To date he has changed O2 sensor, purge and canister, throttle body, gas cap and the sensor at the pedal. So I'm driving home from work and engine light comes on again. I'm close to autozone and pull in. They scan it and am told it has a P0446 code. They tell me this alone will not generate reduced power, my mechanic confirms via phone conversation. I continue to keep the car above 3/4 of a tank for a few days in an attempt to avoid reduced power. So yesterday I'm driving and car is running great other than the ses light on. Get below 3/4 of a tank. Then I get the chime and reduced power light. This time the car starts idling extremely rough. I was able to put the accelerator to the floor to get up to about 20 mph to get to a gas station. I fill up, pull of to the side and disconnect the battery for 30 minutes, this usually clears the code, so I could get the car back to my mechanic. Now something really has me confused. I start the car and both ses and reduced power light are on but the car will accelerate, so I attempt to drive. Turn my lights on, no acceleration, turn lights off and I'm able to accelerate. Car is at mechanic currently but I'm extremely frustrated with this vehicle. I get a new code every week. Any advice would be appreciated. Not sure it's relevant but the dash lights come on when I break as well.

 

Ehhhhh, I'm NOT a mechanic, but I'd suggest having the charging system checked out and the battery load tested. This sure sounds more like an electrical issue to me more than anything else. And find yourself someone who knows about Saturns. Someone is taking advantage of you. Maybe Drop Dead will chime in. I THINK he knows about the Ions.

 

I don't believe our mechanic is taking advantage of me. He's a friend who is a mechanic who does work on the side. He's done plenty of work for us in the past.

 

Looks like your mechanic has been chasing evap codes. I have never had an evap code cause a drivability issue. Now the dash lights coming on when you step on the brake pedal is probably an indicator of the real problem. Something is looking for a ground and is finding ground backfeeding through the dash lights and probably other lights you don’t see while driving. Start at the battery and check all cable and body connections. I do not own an Ion as a disclaimer however I work on many different problems on many brands.

 

EDIT: Below assumes P0446 was real. Uncertain]

Ok,

I'm known for writing novels when answering questions. Here is another.

Unless we have access to the codes he found along the way, we can't tell you what was originally wrong. But in the overall scheme of life that is in the past so there really isn't any point unless you know the initial codes. That might give us a reference point.

Anything that seems to trigger consistently as referenced by the state of something else, in your case SES and reduced power at 3/4 tank, would seem to point to at least 1 condition which still exists and has throughout the entire time you have had this problem.

Some of the things already replaced make sense. Some don't. This is a loaded statement because I don't know what codes he was getting. But if p0446 has been coming up throughout, then things like throttle body, throttle position sensor at the accelerator, the oxygen sensor don't really make sense other than would directly affect engine performance. What I mean is that they would affect the drivability, but without codes to support their malfunction, those are not things I would try first.
Again I do not know what codes he was going off of. Those items seem to be logical if blindly diagnosing the performance issues. But he isn't.

Gas cap, canister, purge solenoid valve can all cause the code listed above.

​​​​​​But there are other components of/issues with the EVAP system that may still contribute to a p0446.

[EDIT: P0446 may not be real]
P0446 Description
Powertrain Control Module (PCM) monitors the performance of the Evaporative Emission (EVAP) system by applying a predetermined level of vacuum to the EVAP system then monitors the vacuum decay rate.

So if the vacuum decays too quickly, it means either the EVAP system is not properly sealed or the determination the vacuum bleed off rate is not correct.

The EVAP test is being run over and over as you drive down the road. The PCM relies on the tank fuel pressure sensor to determine how fast this vacuum is decreasing. If it is not reading correctly, the calculation will be off and the code set. In your case it may be that the pressures it is reporting are correct when the tank is full or above 3/4 but as more of the volume of the gas tank becomes available to pull the vacuum on, the pressure sensor readings become inaccurate.

I find it difficult to believe, other than the canister being full of gas, that the vent valve and purge valve would work fine until you reached 3/4 on the fuel gauge. He has replaced several parts of your EVAP system already.

​​​​​ There are indeed other ways in which the EVAP system cannot be completely sealed. However, if these leaks were present, I would expect them to be affecting the EVAP vacuum test all of the time.

I suppose it is possible that the other leaks if present are not bleeding off sufficient vacuum when the tank is mostly full to make the test fail but the rate at which they bleed the vacuum should not be changing regardless of gas tank level.
---_----_
Another place that may be allowing the vacuum to bleed off is a hole somewhere in the line from the EVAP purge valve 2 the intake system is then not sealed
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Edit [IF P0446 is real] I haven't heard you mention an EVAP smoke test which is probably the best next step, it should show you what's leaking, where, and when. It's not
​inexpensive but will likely lead you to the source of the problem.

I am not an ion guy. I have no idea why a code like this would lead to reduced power other than the PCM being cautious knowing that the system is somehow leaking.

 

I will talk with my buddy about the past codes if you guys think it will help. I'll definitely ask if any additional codes came up with the code Autozone gave me. And I'll look into a smoke test. So much was going on at the same time this last trip I was dumb founded. I'm not a mechanic. My buddy is a mechanic at the school bus barn but is definitely not a Saturn guy. Thanks for the information hopefully it will help.

 

First off, I need all the codes that's the car has thrown.

second, throwing random codes every time the sell comes on makes me think the fuse box isn't grounded correctly.

Third, check the filler tube for the gas for cracks.

Evap shouldn't cause drivability issues. Motor issues will. Which random codes makes me think electrical. Start with all ground. Clean throttle body and maf. Check wiring.

 

Apologies,

I scr the poooooch om this one. I missed the last line about braking --> dash lights. Do you mean dash WARNING lights? Do the lights go off when you let off the pedal?
If so, it MAY indicate a bcm issue, but not necessarily.

+1 on an electrical issue.

Indeed, evap codes should not cause drivability issues nor should they trigger limp mode.

And if the car is playing musical codes, you don't really have any idea which are related to the actual problem and which are collateral damage due to the way things are wired (more than one component on a subcircuit.
I would definitely get a wiring diagram and see what else is on the circuit with the EVAP components.

Per Andy, if you've lost a ground somewhere, the current that WAS flowing through that path to ground will flow through the easiest alternate path it can to get to ground -- if it can do so. You can also end up with situations where the current will flow through circuits it was never designed to, thereby screwing up the behavior of those circuits, which may or may not trigger codes as a result.

It sounds as though he's replaced 2 EVAP system components and you have a code for a 3rd, so I would start there circuit wise.

Also -- hold off on the smoke test. Run that only if it is truly narrowed down to an evap issue.

Again,
Apologies

 

On Fords the evap monitor does not run until the fuel level is between 1/4 and 3/4 full. I would imagine most cars need to meet the same requirements for the monitor to run. An empty tank is just air and a full tank is all gas and no air. The Fords also have to be above freezing to run the monitor.

 

And Saturns are the same (per the GM drive cycle).
Forgot about that too.
Nice catch, Andy.

So it's looking like it MAY actually be an evap issue.

Too many mistakes for me.
I'll watch this one from the sidelines.