i hope this is the right place to post this. I love my trailblazer, and its breaking my f***ing heart. I recently had the driver side steering knuckle, lower control arm, and tie rod replaced and aligment fixed. I was excited cause now i could get it inspected. Problems arise from here. Got the oil changed, and failed the inspection. Top brake light works, but not back side brake lamps. Got home, pulled the fuse and its good. Went to start my 03 trailblazer ls 4.6 il 4x4 and now got a reduced engine power light and wont start. Wtf happened to my girl? It was running perfect till after i got back home. Any responses will be greatly appreciated. Had a mobile mechanic come by, and he "thinks" its the fuel pump. But was not positive.
Reduced engine power light outta nowhere
- Thread starter Whoy
- Start date
It's a fine place. Welcome! Glad you discovered us.
How many miles?
Ever removed the throttle body to clean behind it?
The mobile mechanic (if they were competent) should have checked for codes. I think he's a diagnosGUESSER not a diagnostician. The REP lamp ALWAYS sets additional codes that can lead you to one of the three typical causes - the Accel pedal sensor assembly, the throttle body position sensors, or the electro-viscous fan clutch. Or the wiring tying all them together. It's never the fuel pump by itself that sets off the REP lamp. Can you buy a code reader and check them for more clues?
Which fuse did you check for the brake lights? Rear #34 is the one. It could be two blown lamps, or two bad circuit boards (where the lamps plug into) or a corroded connector harness where the vehicle plugs into the PC boards. Aftermarket lower cost units are available at any parts store. Do you have a meter and some electrical troubleshooting experience?
How many miles?
Ever removed the throttle body to clean behind it?
The mobile mechanic (if they were competent) should have checked for codes. I think he's a diagnosGUESSER not a diagnostician. The REP lamp ALWAYS sets additional codes that can lead you to one of the three typical causes - the Accel pedal sensor assembly, the throttle body position sensors, or the electro-viscous fan clutch. Or the wiring tying all them together. It's never the fuel pump by itself that sets off the REP lamp. Can you buy a code reader and check them for more clues?
Which fuse did you check for the brake lights? Rear #34 is the one. It could be two blown lamps, or two bad circuit boards (where the lamps plug into) or a corroded connector harness where the vehicle plugs into the PC boards. Aftermarket lower cost units are available at any parts store. Do you have a meter and some electrical troubleshooting experience?
He had a computer but did not tell me the codes. I replaced the bulbs and i believe it has fixed the issue. Will double check when it gets dark. Its has a little over 158000 miles. Never messed with throttle body. No tester, and no electrical experience.
yodaddy4200
Member
- Feb 3, 2013
- 350
yodaddy4200
Member
- Feb 3, 2013
- 350
Ok. It will start now. But idling very slow. Can not press knob in on shifter. Step on gas, and you can hear it rev but rpm goes up extremely slowly. Im sorry but i dont have money for the computer.
If you can't get it out of park, that's going to be hard. Is there a voltmeter at the very least in your house or a buddy's? Might get stuck at the parts store and then you'd need a tow, but you know that.
Throttle body is a big suspect in my mind.
https://www.youtube.com/watch?v=VdvgsaDmkac
Throttle body is a big suspect in my mind.
https://www.youtube.com/watch?v=VdvgsaDmkac
KNBlazer
Member
- Feb 8, 2012
- 811
A good scanner cost about $150.... A code reader is probably about $60 or so.... In the instrument cluster, are there still any lights on? You should first take care of the basics, which include cleaning the throttle body as Roadie suggested.... It's as much work as changing that rear lamp... there are videos on youtube you can use as a step by step guide...Whoy said:
no voltmeter. probably use one from work. kinda funny that i work for a metrology lab but dont have any of those pieces. would cleaning the throttle body possibly fox the issue or is it just to help clear things up.Whoy said:
If it started, that's a huge improvement and rules out the fuel pump for now. But there's a lot of other deferred maintenance that might be at work. All depends on exactly how the idle is behaving.
BlazingTrails
Member
- Apr 27, 2014
- 19,409
my question: was the battery disconnected? if not then the throttle body probably would not cause a problem instantly like that. if it was disconnected then I would def agree that is the problem, i had the same thing happen to me.
was pretty bad. caked on black crap. bud not real think. started it up. looks like the engine is rocking when idling. still can not push in the knob. is it possible to post video?
i apologize, but im confused. ive only took off the post off yhe battery. read somewhere that it will reset the computer. probably dumb idea on my part
the rpm needle rises slower than the engine sounds when i step on the gas if that makes sense.
it sounds as though its trying to be an old school muscle car. i have the service engine soon, and reduced engine power on still.
all 3 brake lights now work,. i switched out the bulbs. the ses light is solid, does not flash. but i do not understand how a bad solenoid would cause all these problems.IllogicTC said:
BlazingTrails
Member
- Apr 27, 2014
- 19,409
that's fine, but now that you have cleaned the throttle body you should disconnect it again. turn off all the a/c switches, while it is disconnected turn the key on in the car then turn it back off to make sure the system is drained. reconnect the battery, then turn the key on but don't start it for 2 min. now start it and let it run at idle for 10 min do not touch the gas. or turn anything on or put it in gear. it will program the idle. hope this helpsWhoy said:
ok, well i got a carmd piece from guy at work. the only code popping up is P1512. but there is no code in the book for it. any ideas?BlazingTrails said:
No P1512 in WHAT book? I see hits for it all over Google. Anyway, that's usually a binding throttle body or one that can't move to the commanded position. Consistent with a gummed-up and sticky throat. Is it a historic old code or a current one?
BlazingTrails
Member
- Apr 27, 2014
- 19,409
I can't seem to get a direct answer for the p1512 code. but it seems to have something to do with the Electronic throttle system. check the connector on the side of the throttle body. reset the code and try again.
its the owners manual. it goes from P0010 to P0849. nothing that starts with P1xxxThe_Roadie said:
BlazingTrails
Member
- Apr 27, 2014
- 19,409
The GM Repair manual t/s for both codes tells you to check the TC fuse. for P1512 and P1516
-Brandon
-Brandon
The owner's manual is generally a joke for technical items like that. They want you to take it to the dealer. Trust Google.
whats the tc fuse? is located under back seat or under hood? im trusting google and you guys. fellow tblazer guys.BlazingTrails said:
BlazingTrails
Member
- Apr 27, 2014
- 19,409
I just found this, check it out and see if it will help you figure this out!
http://www.underhoodservice.com/Article/106472/pulling_codes_what_is_our_position_on_this_the_story_of_p1512.aspx
-Brandon
http://www.underhoodservice.com/Article/106472/pulling_codes_what_is_our_position_on_this_the_story_of_p1512.aspx
-Brandon
BlazingTrails
Member
- Apr 27, 2014
- 19,409
Is that manual really good for anything at all?? it's like reading a "driving for dummies" book lmaoThe_Roadie said:
found that site as well. basically im going to have to put it in the shop i thinkBlazingTrails said:I just found this, check it out and see if it will help you figure this out!
http://www.underhoodservice.com/Article/106472/pulling_codes_what_is_our_position_on_this_the_story_of_p1512.aspx
-Brandon
BlazingTrails
Member
- Apr 27, 2014
- 19,409
It's in the schematic. Front Fuse #23. Labeled ETC. Should be in the Owner's Manual, as lame as it is.
replaced #23. two codes P1512, and now 0340. wtf is going on? now there is something wrong with the camshaft