Envoy reduced engine power??

[Polarboyz]

Hi, this is my 1st post and unfortunately it's a bit lengthy.
'02 Envoy 3 weeks ago needed the cooling fan clutch replaced cuz it was stuck on high. I did that and all was good for about a week. Then my wife went to work and as she pulled in the lot and got a message from the DIC saying low oil pressure/stop engine and it killed on its own. She started it up and parked it, everything was fine. She checked the oil and it was good. The DIC even said 68% life left. It was fine for the next 4 days. Today she ran some errands and in a parking lot it got the Service engine soon light and the Reduced engine power light and could barely move. She got it parked and shut it off, did her errands, came back out and it started and ran just fine with the exception of the SES light being on.
It has been about 15* below zero for the last few nights and highs of 0* Don't know if that has anything to do with it. I will try to get the codes tomorrow from it. Just tryin to get a little input from anyone cuz my wife is scared to death to drive it!: eek: She's been lucky that the problems have happened in parking lots and not on the freeways.

Sorry so long and thanks for any help.

Polarboyz

[evilpeanut]

Do the easy things first. Try some dry gas. With temperatures that low you might have some condensation in the tank. My sisters TB had a reduced engine power light and it turned out to be a bad tank of gas....

[Blazernut]

Should be interesting to see the codes that come up. Keep us posted. Would be nice if it was a simple sensor malfunction.

[Polarboyz]

Ok guys, I got the codes. 1)P1515 = TPS difference between actual and detected throttle position 2)P1516 = TPS sensor out of range 3)P1512 = Predicted and actual throttle position sensor. After getting those I cleared them and went for a drive. Everything was fine and the SES light was off. Stopped and got new gas since it was between 1/4 and 1/2. Came home and read codes again. There weren't any.
The only things I can find that may have caused this is the Accelerator Pedal Position sensor (APP) or the Throttle Position sensor (TPS) but I don't know which to do first or if I even have to do anything. Unfortunately I still don't think my wife will drive it until I do something. She took my truck today.

Any more thoughts?

[w_bailey04]

my mothers tb just needed a bottle of that HEET gas line antifreeze. we have had some cold nights here in michigan

[PROSPHOTO]

Have you ever cleaned your throttle body? The TPS is built into the throttle body [motor] and you would have to replace the entire Throttle Body.

However...don't go changing parts b/c you think it's faulty
A proper diagnosis is in order if the problem persists

If you have the extra $$ floating around to replace good components, there are plenty of members that wouldn't mind it

First step for you will be to remove the throttle body & clean it (click here for instructions)

[Polarboyz]

She took mine again today. I took the Envoy and put 60 miles on it and got 1 code of 0014 (nothing major) Ran fine with no issues. We'll try again tomorrow but I'm really thinkin (hopin) it was just bad gas. Keep ya posted.

[PROSPHOTO]

EVERY emission code is major in these trucks, unless you like spending your paycheck on gas

A quick check that you can do is to unplug the camshaft phaser and look at the connector (#2 in the pic)...if the inside of the connector is wet with oil, it needs to be replaced
You will also need to manually check the oil pressure in the truck as part of the diagnosis; don't rely upon the gauge on the dashboard. Low oil pressure will also cause this code & since you got a warning, it's definitely something to look into


Also...there is a bulletin [possibly] addressing your concern:

Built Prior to the following VIN Breakpoints:

VIN Breakpoint

GMC Envoy

22244601

Condition:

Some customers may comment on the Service Engine Soon lamp being illuminated, a delayed transmission downshift and/or excessive fan noise. Upon investigation, the technician may find either a DTC P0014 (Cam Phaser Performance), DTC P0116 (High Sided Coolant Rationality) and/or DTC P1683 (Low Power Counter Failure).

Correction:

Reprogram the powertrain control module (PCM) on all affected vehicles, as identified above, including vehicles in new dealer inventory, used inventory, and any that return for service in or out of warranty.

Using a Tech 2 scan tool and TIS 2000, verify that the calibration programmed into the vehicle’s PCM has been programmed since August, 2001 or later. The GM Vehicle Inquiry System (GM VIS) may also be checked to see if the vehicle has been programmed since August, 2001. If the August, 2001 or later updated calibration has not been installed, reprogram the PCM with the latest updated calibration from TIS 2000 version 8.5 for 2001 data update or later.

One more thing...what weight oil are you using? The engine calls for 5W-30; If you're using 10W30, that may be too thick for the temps you're experiencing
Your owners manual states:

If you are in an area where the temperature falls below
-20F (-29C), consider using either an SAE 5W-30
synthetic oil or an SAE 0W-30 oil. Both will provide
easier cold starting and better protection for your engine
at extremely low temperatures.

[Polarboyz]

Thanks for the info and diagrams! I tried to look at the connector for the camshaft phaser but it's STILL to cold (4) and the plastic started to break so I'll have to wait. Hopefully this isn't toooo dumb of a question but how do I check the oil pressure manually? More tools I bet.
The bulletin is good info to have. My VIN does fall after the one listed so I don't think it pertains to us.
As far as the oil goes, I only use 5w-30 synthetic and on any night that it's going below 20* (above zero) the block heater is plugged in.
Todays test I put on about 80 miles. Did freeway, stop and go, county roads and some city streets. Got no codes. This is really starting to get frustrating! My wife agreed to take it tomorrow and see what happens.: :

[Fishhunter911]

How many miles are on it? When she was having the problems how long has she been driving it?