Reduced Engine Power/Grounds, help me out!

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Mar 11, 2014 | 12:00 PM

Endeka

Thread Starter

Burning Brakes

Joined: Sep 2011

Posts: 871

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From: Alpha/Coopersburg NJ/PA

Reduced Engine Power/Grounds, help me out!

Hi guys,

My car is intermittently throwing the following codes:

P1120
P1221
P1515

And the red herring TCS code:

C1278H

Googling has led me to understand that this is a fault in the throttle position sensor, which may require either that, or the whole throttle body, to be replaced. NBD, I just need to know how to proceed.

The other thing is that so many people have been saying to clean the grounds, and mine are very dirty looking and the posts are a bit rusty, but I cannot for the life of me separate the plastic connector. I've tried with a knife. I've tried with pliers. I've tried pushing in the little tabs. Anybody got a tip on how to do it without breaking it?

Finally, are there other steps besides cleaning the grounds that I should take before I replace the whole TB? Money is really no object here but I don't want to throw it away.

Mar 11, 2014 | 12:55 PM

~~Todd157k~~

Banned Scam/Spammer

Joined: Jul 2006

Posts: 2,911

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From: Simi Valley CA

Cleaning grounds is always a good idea. Use a wire brush (toothbrush size) to clean the lugs and locations.
Connectors: slide the color clip back (or off on some) and set aside. Push tab and release. Put the lock (color clip) back on when reassembly. Shoot some electrical cleaner both halves of the connectors. A little wd-40 on them afterwards helps keep the corrosion down.
TPS: Look up the "throttle relearn" write up. Always start with the simple fix. Let me know if you can't find it.. I saved it.. somewhere.

Hope that helps.

Mar 11, 2014 | 01:19 PM

Endeka

Thread Starter

Burning Brakes

Joined: Sep 2011

Posts: 871

Likes: 3

From: Alpha/Coopersburg NJ/PA

Thanks man. The other thing is that it's very intermittent. Like, this morning before work I was futzing with it, and I couldn't even clear the code, which has never happened before (I'd clear and it'd pop right back instantly), but now it's running like normal. When the code is tripped, it runs very rough, like it's on four cylinders or something. I haven't let it run more than a few seconds like that, I'm just trying to see if I fixed it.

Mar 11, 2014 | 03:01 PM

~~Todd157k~~

Banned Scam/Spammer

Joined: Jul 2006

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From: Simi Valley CA

intermittent is almost always electrical connections. Parts don't usually go bad and fix themselves.

Mar 12, 2014 | 12:03 PM

Endeka

Thread Starter

Burning Brakes

Joined: Sep 2011

Posts: 871

Likes: 3

From: Alpha/Coopersburg NJ/PA

Started it up again and fiddled before work. New Code from the RDCM LDCM:

u1064 on both sides.

What am I looking at here?

Mar 12, 2014 | 02:42 PM

jim993

Drifting

Joined: Sep 2009

Posts: 1,862

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From: Prescott, Arizona

I debated whether to mention this since I hate throwing parts at a problem, but if, when the problem appears, a shutdown and restart clears the problem, then I suspect the ignition switch.

The contacts in the ignition switch slowly burn and get degraded over time and can throw all kinds of codes, since the ignition switch powers up just about everything.

I have had to replace two ignition switches so far. No comm both door control modules was one of many intermittent symptoms, including running on only a few cylinders to flashing instrument cluster lights, service traction control, reduced power and check engine light.

Hard to diagnose, though. If it is the ignition switch and it gets bad enough (like a crank, no start), you may be able to diagnose by leaving the ignition switch on and checking for power with a multimeter at those fuses in the engine compartment fuse box that are powered by the ignition switch, starting with No. 16.

Mar 12, 2014 | 03:10 PM

Endeka

Thread Starter

Burning Brakes

Joined: Sep 2011

Posts: 871

Likes: 3

From: Alpha/Coopersburg NJ/PA

Quote:

I have had to replace two ignition switches so far. No comm both door control modules was one of many intermittent symptoms, including running on only a few cylinders to flashing instrument cluster lights, service traction control, reduced power and check engine light.

Holy hell, this is it. This is frigging it to a T after all these weeks. It even threw a weird "column lock" code that went away with restart even though I did the CLB with the nice compliance kit months ago. Had flickering dash lights for near 6 months before this started, took the battery in to get checked 3 times, perfect all three times. Then this started; the RDCM LDCM codes are VERY intermittent, perhaps every 5-6 times its started.

I'm doing this if cleaning the grounds doesn't work. It's just so close, there's just no way this isn't it.

Last edited by Endeka; Mar 12, 2014 at 03:15 PM.

Mar 12, 2014 | 03:25 PM

jim993

Drifting

Joined: Sep 2009

Posts: 1,862

Likes: 594

From: Prescott, Arizona

Also check your connections at the battery. I also had flashing instrument cluster lights with a battery cable not fully torqued.

10 foot pounds minimum.