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2002 gmc envoy_slt_xl
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Discussion Starter · #41 ·
process of elimination. check all the pesky wires and connections and double check them to eliminate all other possibilities. the light coming right back on or after a delay could be a clue. maybe tell you if its mechanical or electrical.
Yeah, I double checked the wiring yet again last night. All good there, 12V on the brown wire, and ground on the other, no shorted wires, and so far the P0013 is not showing up anymore. I believe the system commands a certain actuator % for the phaser and if it's not met, the P0014 code moves to pending, then after three cycles, if it's still not met, it will become a hard fault and the CEL will come on. My OBD2 reader can scan the hard faults as well as pending faults. The P014 was confirmed while driving around last night.
 

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2004 chevy trailblazer_lt
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OK on being east of Elkhart. Went there as a kid for vacation to visit a family friend and had a great time. Only thing I really remember about Elkhart is the river that runs through the city. Also, a guy I went to graduate school with lives in Elkhart - took a job with Miles Lab/Bayer.

I know what you mean about the snow, the ice, the salt, sand, rust, bubbling paint, etc. I grew up in Omaha, NE and rusted out cars were the norm! When my wife and I bought our first new car in 1992 there in Indianapolis, we got it Ziebarted and had it treated every year thereafter wherever we moved to (Connecticut and Maryland) until the local Ziebart went out of business for what I believe was breech of the franchise agreement. He got lazy and cheap, didn't bother to apply the Ziebart products according to their technical manuals and he was purchasing and using non-Ziebart detailing stuff.

I know what you mean about wanting to get rid of DTCs, wanting the vehicle mechanically correct and getting better gas mileage. I know we get about 17 - 20 MPG on the highway with our 1999 Silverado, and in the next few weeks I'll be towing a loaded U-Haul trailer (and the truck will be too) from the midwest back to Maryland and I'm expecting to get 12.5 MPG if I'm lucky. Needless to say, I've already figured out where to get "cheap" Top Tier gas along our route.

Good luck with the diagnosis and repair of what's left of the P0014.
 

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2004 Trailblazer LS 4.20 L
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A very good childhood friend of mine moved to Elkhart years ago. Weird. Anyways, did you check the upstream O2 sensor and wiring? not sure if that would trip that code or not but they can cause poor mileage i hear. One other thing is of course spark plugs. Newer should improve mileage. Only other thing to clean is the air filter and the fuel injectors. pretty much. Although, check your manifold bolts. Some of them are found quite loose ive heard and I've heard tightening them stops some engine codes. forgot all about that one.
 

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I've had P0013 & P0014 for years now. Finally decided I didn't want to deal with the rough cold starts and 10mpg gas mileage anymore. Below are the things I've done.
I've read countless threads here, as well as all the videos I could find on Youtube to try to solve this. I'm focused on the P0013 circuit malfunction, as this is likely causing the P0014 over advance condition, as the PCM is not able to control the solenoid/phaser.

VVT solenoid w/ oil change 3 months ago (generic)... no change

Camshaft phaser/timing chain replaced w/ oil change, one week ago... no change. The old phaser was crusted and locked up. It took some working with a pipe wrench to get it free. Once free, the spring tension was very low, so I suspect it had been not working for a very long time and had seized up.

Pulled the VVT and made sure the screens were clean, they were.

Swapped PCM, after a few cycles the codes were back, no change.

I've also probed the VVT solenoid harness pins, +12V on one and ground on the other. I've unplugged the harness from the PCM and checked for a short circuit to ground on the wires, and all was good. I've applied 12V straight from the battery to the solenoid and can hear it clicking just fine.

Here is what I plan to try in the next day or two....

Check the resistance on the VVT solenoid, should be 8-10ohms.

With engine idling, apply direct battery voltage to VVT solenoid. This should stall or stumble the engine, this will tell me that the system would work if it were to get voltage/command from the PCM.

If that tests okay, I will probe the harness, run the wires into the cabin with a spare solenoid and multitester, drive around to see if the PCM is actually sending the signal under normal driving conditions, however I'm wondering if the PCM will not do anything with the VVT circuit after the circuit is checked and the P0013 code is there, might need to clear the codes, then immediately take it for a drive.

Something I thought was strange was that I probed the harness, verified 12V, but the second the harness is plugged into the VVT solenoid, the voltage goes to 0, and the solenoid never clicks. A tech video that I watched showed that this was normal, so must just be how the PCM works with controlling the voltage & pulse, but just seemed strange to me, apparently that is normal.

Can anyone please give me your thoughts? I've spend so much time and $$ on this issue, I feel like I have to get it fixed.
TRY CHANGING YOUR VAPOR CANNISTER PURGE VALVE/ SILENOID. That fixed my rough idle issue after MANY attempts.
 

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2002 gmc envoy_slt_xl
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Discussion Starter · #45 ·
TRY CHANGING YOUR VAPOR CANNISTER PURGE VALVE/ SILENOID. That fixed my rough idle issue after MANY attempts.
Thanks, I had gotten some strange code a while back about that, however it's since disappeared, I'll look into it though.
 

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Discussion Starter · #46 ·
Okay, pulled a used phaser from the salvage yard. I was already there returning something anyway, so just decided to grab it while I was there. I hooked up a battery and scanned the PCM to make sure there are not P0013 or P0014 codes present on the donor engine. I'm going to swap this into my truck and see if the issue is resolved. During my searching, at some point, someone had made a very detailed post somewhere showing how to replace the phaser, keeping the front cover in place, and using special timing chain clamping tools to keep it from slipping off the lower pulley. Does anyone know where this guide may be? I can't seem to find it anywhere.
 

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Discussion Starter · #47 ·
OK on being east of Elkhart. Went there as a kid for vacation to visit a family friend and had a great time. Only thing I really remember about Elkhart is the river that runs through the city. Also, a guy I went to graduate school with lives in Elkhart - took a job with Miles Lab/Bayer.

I know what you mean about the snow, the ice, the salt, sand, rust, bubbling paint, etc. I grew up in Omaha, NE and rusted out cars were the norm! When my wife and I bought our first new car in 1992 there in Indianapolis, we got it Ziebarted and had it treated every year thereafter wherever we moved to (Connecticut and Maryland) until the local Ziebart went out of business for what I believe was breech of the franchise agreement. He got lazy and cheap, didn't bother to apply the Ziebart products according to their technical manuals and he was purchasing and using non-Ziebart detailing stuff.

I know what you mean about wanting to get rid of DTCs, wanting the vehicle mechanically correct and getting better gas mileage. I know we get about 17 - 20 MPG on the highway with our 1999 Silverado, and in the next few weeks I'll be towing a loaded U-Haul trailer (and the truck will be too) from the midwest back to Maryland and I'm expecting to get 12.5 MPG if I'm lucky. Needless to say, I've already figured out where to get "cheap" Top Tier gas along our route.

Good luck with the diagnosis and repair of what's left of the P0014.
The city of Elkhart if fairly forgettable. They are trying to revitalize downtown and doing a pretty good job adding and making it a place people want to go. Adding an ice skating park, adding a river walk, new apartments, aquatic center, etc, but it's still Elkhart. People seem to come here for jobs, mainly the RV industry. I live right down the road from the RV hall of fame. Some of the surrounding areas & towns are nice. I've known a few people who have worked there, it's been shut down for some time.

A very good childhood friend of mine moved to Elkhart years ago. Weird. Anyways, did you check the upstream O2 sensor and wiring? not sure if that would trip that code or not but they can cause poor mileage i hear. One other thing is of course spark plugs. Newer should improve mileage. Only other thing to clean is the air filter and the fuel injectors. pretty much. Although, check your manifold bolts. Some of them are found quite loose ive heard and I've heard tightening them stops some engine codes. forgot all about that one.
Strange you guys have connections to this place. Yes, checked/replaced upstream/downstream 02's. They were bad at one point, but replaced them recently. New OEM plugs, and replaced ignition coils (not oem, but seem to be working well). Manifold was off, all new gaskets when I did the timing chain & phaser replacement. I'm 99% positive the poor mileage is from the VVT system not functioning.
 
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