[HarrisonBP]

When it's cold outside my Malibu starts fine, but immediately the DIC displays the ENG PWR REDUCED, and has no response from the accelerator. To get my car to drive I must warm it up, let it idle around while I try to clear codes (which immediately return)... takes anywhere between 15min, and an hour and a half. The codes that are always displayed are P1518 and P0443. I have inspected wires, connectors, cleaned the MAF (which looked fine). Has anyone had this problem? Can anyone help? I don't want to take it to the dealership and have them tell me that it was something simple, and charge me a grand or so.

Thanks in advance.

 

[Unfettered]

Sounds like you might have some water in the system that is freezing up, depending on where in the country you are. If you have a garage, put it in and try to get it above freezing and see if the issue clears.

The P1518 is a throttle body code and the purge valve. Moisture in these along with cold temps will cause errors due to icing conditions.

 

[HarrisonBP]

Thank you for the reply, but unfortunately I dont think that is the case. I live in Southern Louisiana, so when i say cold weather i mean anything below about 60° lol. Again, thanks though.

 

[Starship]

Wow, those DTCs are the first on this forum. P1518 (No communication between electronic throttle module and PCM) means data errors over the serial data circuit between the PCM and Throttle Actuator Control (TAC) module. In the absence of other TAC fault codes, I'd suspect a poor electrical connection (broken strands inside the electrical connector or wire insulation). The TAC module is component 7 in diagram http://cid-54465800aad91b49.office.live.com/self.aspx/pub/Top%20of%20LX9.GIF. If you're lucky, you may be able to feel a soft spot on the exposed wire(s) near the TAC module indicating broken strands. Cracks on the insulation where the wires are bent into the connector are also suspect. Otherwise, you'll need to check for presence of proper voltages (both 5V and 12V with key on, engine off) and continuity on individual wires. See the wiring diagrams below.

P0443 (Evaporative Emission Control System Purge Control Valve Circuit) means there's a problem in the wiring between the PCM and EVAP purge solenoid. Again, I'd suspect a poor electrical connection. The EVAP purge solenoid is component 6 in the diagram above. The wiring between it and the PCM is included in the wiring diagram below.

The following are the wiring diagrams:

http://cid-54465800aad91b49.office.live.com/self.aspx/pub/va197193.pdf
http://cid-54465800aad91b49.office.live.com/self.aspx/pub/va197194.pdf
http://cid-54465800aad91b49.office.live.com/self.aspx/pub/va197195.pdf
http://cid-54465800aad91b49.office.live.com/self.aspx/pub/va197196.pdf
http://cid-54465800aad91b49.office.live.com/self.aspx/pub/va197197.pdf

 

[HarrisonBP]

Thanks Starship. So today, after getting my car running correctly, I kind of played hookie from work and worked on my car a little. I cleaned my throttle body (which was quite dirty and gummy) which was suggested to me on another forum. The idea is that the butterfly valve sticks which causes there to be a discrepancy between the pedal position sensor, and the throttle position sensor, which makes my computer throw codes. I'll wait till in the morning chill has set into my car, and if it's fixed... thank god. If not, I will have to learn to read a wiring diagram, something I have been avoiding for years. Thanks again, and I will let you know what happens in the morning.

 

[HarrisonBP]

Cleaning the throttle body did not help... FML, I hate electrical problems.

So, I really don't know much about reading wiring diagrams, or automotive electrical in general. I get the basics (12 volt, DC), but that's about it. So can you tell me how to "check for presence of proper voltages (both 5V and 12V with key on, engine off) and continuity on individual wires", or tell me how to learn to do this, and what I need? Please speak slowly, and use small words...

Thanks

 

[Starship]

There're a lot of references on the web on how to use a multimeter to troubleshoot automotive electrical problems. I'm sure I do things in a certain way without even thinking, depending on the situation and thus I can't really help with the how-to. If you're as green as you claim, you may want to consider taking it to the professionals.

Like I said, you may get lucky and find a soft spot on the wire(s) coming out of the TAC module. It may just take reseating the electrical connector even. Otherwise, you'll need to verify 12V on the PNK/BLK wire (terminal 18 at the TAC connector) with KOEO (be sure not to short it to the ground or you'll blow the Electronic Throttle Control fuse). The serial data circuit is on the ORG/BLK wire (terminal 16) and TAN wire (terminal 7). They go to terminal 2 and 3, respectively, on the connector C2 at the PCM (that connector is component 9 on http://cid-54465800aad91b49.office.live.com/self.aspx/pub/Left%20Rear%20of%20Engine%20Compartment.GIF). You'll need to verify the continuity on those two wires.

 

[pimpinLTZ]

I had a "reduced engine power" event today. Yay!

Funny story actually, (not really) I was on my way to the dealership to get my tires rotated and some interior trim fixed that was loose. I stopped by a car wash first to spray some of the salt off and snow in the wheel wells. As I was pulling out of the bay, there was a patch of ice that made my TC kick in. Immediately after that, the chime went off and I got the "reduced engine power", "service ESC", and "service traction control" messages on the DIC.
Apparently, they come as a trifecta
The car was verrrry sluggish, but I had to make it a couple miles or so to the dealer. It would get up to some speed, but it just took a while to accel. The cars behind me loved me.
Was not able to pick up the car yet today as they are waiting on a trim piece they ordered, but I talked to them and they said they replaced the throttle position sensor. I really hope that's all that is wrong, cause I'm driving down to Florida on Sunday for three weeks.

God I love this Car.
It's so nice to have a new car I feel like I can count on.

Oh, and I'm at 13 months old @ around 16,000 miles.

 

[pimpinLTZ]

Mods,
Can I change my name to LimpinLTZ?

Thanks...

P.S. whoops, this is gen 5, 6 thread LOL...

 

[2009ChevMal]

Did changing the throttle position sensor work? I'm having all three errors right now and they came on all at once.

 

[HarrisonBP]

Did changing the throttle position sensor work? I'm having all three errors right now and they came on all at once.

Turns out I didn't even have to try that. Though I had originally checked every (and I mean EVERY) fuse in the car it turned out that one of my fuses under the hood, for the TCM I believe, had a very (and I mean VERY) slight bit of oxidization on it.

It was a huge pain to figure this out, I'll spare you the details. Now, when it's cold, I have to keep extra fuses on me because every few months that one fuse, and as far as I can tell only that fuse, gets that same oxidization. It's not blown, but it does test differently on a meter than a new fuse.

This is a recurring problem that is far easier to deal with than actually fixing whatever the problem is. I hope this helps, please let me know.

 

[autodesigner]

I had the same issue on my way to a very important job interview. Of which I wasn't able to make it. My Malibu let me down again. Anyway, the problem for me was the accelerator pedal had to be replaced. Ran about $375 at Chevy dealer.

 

[Jak]

I cleaned my throttle body with some throttle body cleaner and that fixed the problem and changed my air filter

 

[Joseph Dela Cruz]

try to check your antifreeze it could be low..