thanks fireman. i bought a scanner (actron cp9125) but don't know what is causing all these codes. i think 843de is curious though.

 

Well I'm curious too, so post up an answer when you get one.

 

I am waiting for the cat to be killed too!

 

will do guys. have a great night!

 

It does get a bit frustrating for everyone when advice is asked for, and the OP seems to refuse to listen to or acknowledge the advice given, and wants to go off on a tangent. You were not being YELLED at - it was pointing out to you, that you were not following the advice being given (hint: ChevyMgr is seldom wrong - if he says get the codes as the first step........).

Without the codes, you were expecting us to second guess for you, all the while you were following advice from a different forum. And now you have a new gas cap you quite likely didn't need.

At least you got your codes now which is a good step forward.

 

OK, service manuals on the desk in front of me, two cups of coffee gone...now time to address the codes and stuff like that. I'll group them by their relationship.

P0101 & P0102 Mass Air Flow (MAF) Circuit Range/Performance Problem & Mass Air Flow (MAF) Circuit Low Input

These codes can mean the following....

The MAF may be disconnected, or a wiring connection may be bad
The MAF may be dirty or otherwise contaminated (Note: if you use a reusable oiled air filter, be careful not to apply too much oil or that can contaminate the MAF).
The MAF sensor may be faulty
The vehicle computer may be faulty

Now what you can do....

The simplest thing to do is to reset the code and see if it comes back. Then start with the cheapest, easiest repair procedures:

Verify that the Mass Air Flow Sensor wiring is connected properly and that there are no broken / frayed wires.
Inspect for any air leaks near the MAF sensor.
Take the MAF out and clean it using a spray cleaner such as brake cleaner or electrical contact cleaner. Be gentle with the sensor(this procedure can ruin the sensor anyway, just so you know)
Check the voltage of the MAF sensor...requires a scan tool
Replace the MAF sensor.

OK now for P0113

P0113 Intake Air Temperature Circuit High Input

This code can mean....

Internally failed IAT sensor
Faulty connection at IAT sensor
Open in IAT ground circuit or signal circuit
Short to voltage in IAT signal circuit or reference circuit
IAT harness and/or wiring routed too close to high-voltage wiring (e.g. alternator...not really possible in the HHR)
Faulty ECM (less likely but not impossible)

Now what you can do....(Warning!!! This is straying into professional technician territory here)

First, if you have access to a scan tool(which I just remembered that you do), is there an IAT reading? If the IAT reading is logical then the problem is likely intermittent. If the reading is less than -30 degrees, unplug the connector. Install a jumper wire between the harness connector signal and ground circuits. The IAT temperature reading on the scan tool should be maxed out at the high end. For example it should be 280 degrees Fahrenheit or higher. If it is, the wiring is okay, and it may have been the connection. If it isn't install the jumper wire between the IAT signal circuit and the chassis ground.

If now the IAT reading on the scan tool is maxed out then check for an open in the IAT ground circuit. If you get no reading at all on the scan tool, it's likely that the sensor signal is open or the 5 volt reference is missing. Check using a DVOM (digital volt ohm meter) for a 5 volt reference. If it's there, then unplug the connector at the PCM and check for continuity on the IAT signal circuit between the PCM connector and the IAT connector.

OK, now for P0442 & P0455

P0442 & P0455 Evaporative Emission Control System Leak Detected (small leak) & Evaporative Emission Control System Leak Detected (no purge flow or large leak)

These codes can mean the following....

A loose or improperly affixed gas cap
A non-conforming gas cap (i.e. not factory/original brand)
A small leak/hole in a fuel vapor hose/tube
Other small leak in EVAP system
Faulty vent o-ring seal

Now what you can do....(I think you've already replaced the gas cap)

Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
Otherwise, replace the gas cap, or
Inspect the EVAP system for cuts/holes in tubes/hoses

And lastly we have P0496

P0496 EVAP Flow During a Non-Purge Condition

This code can mean....

Purge or Vent Solenoid Failures
Plugged EVAP canister condition
Failed EVAP pressure sensor

What you can do....

Using a scan tool, verify function of EVAP purge solenoids

Phew! OK, you have three groups of problems, are they all related to one another...maybe. While each group needs to be addressed by itself, my thinking is that there may be a problem in the vehicle's wiring harness or with the ECM itself. But that is just my opinion, should you take it to your dealer or an independent technician that you trust, if it were me...yeah I would. Just threw a lot of info out there at you, and I'm hoping others here like Whopper will weigh in with their opinions, and/or experiences with similar issues and what the eventual solutions were.

 

I am pretty sure the IAT sensor is part of the MAF itself and therefore would be part of the same component let alone sytem of the car. In other words if one is bad you replace both because they are the same part.

I do agree that this seems like a one thing causing multiple systems to fail at the same time. When I see that many items failing I always try to see if they share one ore more fixes. In this case electrical like 843 mentioned would be where I would start. This could be wiring or the ECM. If you start to see non engine related codes then perhaps the BCM but it doesn't sound like you have any of those.

What kind of scanner did you use? I ask because in the past a lot of scanners only read enging codes but not body codes such as airbags or instument clusters and such.

 

You are correct, the IAT and MAF on the HHR are one assembly, the IAT function is one output channel. With both IAT and MAF codes present it does suggest a failure of either that component or an issue with the wiring harness or possibly the ECM.

 

Thanks guys. A lot of good info. 843 you did all that on just two cups WOW! I put the new cap on and erased the codes. Drove to work and back and engine light is still off for now. Keeping fingers crossed. Again,thanks.

 

Sounds to me like somebody replaced the air filter and forgot to connect the MAF back up properly (been there, done that). Also the purge valve is right there also, it's that thing with hoses and wires attached to the driver side of the valve cover.