2005 chevy electrical problem

98dango

Expedition Leader
OK I could use some help please.

My wife's Tahoe a few weeks a go shut off driving down the road. The dash flashes and by dash I mean every thing at the same time like your cycling the key. The ignition relay clicks with this. Now I can't afford to take this to the shop but I have more free time than I know what to do with at the moment.

This is a loaded 2005 Tahoe LT 5.3

Any and all help is much appreciate.
 

Larry

Bigassgas Explorer
I’d start by pulling codes. There could be a passive code in there even though the “Service Engine Soon” light may not be on. I suspect a fuel pump, cam or crank sensor as the culprit. There should be some code in there that will give you a clue as to which one. Lean bank 1, lean bank 2 codes are indicative of a fuel supply issue while the cam and crank will leave their own specific codes. An intermittent stall is most often crank sensor related. Another thing to look at is to verify the alternator is charging properly. These rigs will not run for long with an electrical system running below battery voltage.

Dash lights will always light up like a Christmas Tree when the engine stops running while the ignition key is turned on so the lights alone do not lend to any clues as to what is wrong. That generation of GM truck and engine are pretty much anvil-like with only a few items that cause issues like this.
 

98dango

Expedition Leader
I'd start by pulling codes. There could be a passive code in there even though the “Service Engine Soon” light may not be on. I suspect a fuel pump, cam or crank sensor as the culprit. There should be some code in there that will give you a clue as to which one. Lean bank 1, lean bank 2 codes are indicative of a fuel supply issue while the cam and crank will leave their own specific codes. An intermittent stall is most often crank sensor related. Another thing to look at is to verify the alternator is charging properly. These rigs will not run for long with an electrical system running below battery voltage.

Dash lights will always light up like a Christmas Tree when the engine stops running while the ignition key is turned on so the lights alone do not lend to any clues as to what is wrong. That generation of GM truck and engine are pretty much anvil-like with only a few items that cause issues like this.

Larry the don't light up the flash the whole system will turn on and off not just gauges heater radio all flash at the same time. If I do magically get it to start it will pulse when ideling.
 

98dango

Expedition Leader
When it flashes the #5 relay under the hood clicks this according to the manual I'd the ignition relay.
 

Larry

Bigassgas Explorer
I’m having a hard time following your story here but I doubt you have any issues with theft lock. Security/theft lock issues usually only appear after someone’s been monkeying around with adding aftermarket stuff like radios, etc. or changing ECM’s, BCM’s etc.

You probably already have this but here you go. BTW.. o’s are not the same as 0’s.

DTC P0203 no info. Doesn’t look like a valid code in GM SI2000
DTC P0054 HO2S Heater Resistance Bank 1 Sensor 2
DTC P0060 HO2S Heater Resistance Bank 2 Sensor 2
DTC P0200 Injector Control Circuit
DTC P0230 Fuel Pump Relay Control Circuit
DTC P0443 Evaporative Emission (EVAP) Purge Solenoid Control Circuit

That many codes I would be looking at power and grounds. Without having the truck right here to play with it is hard to steer you down the right path.
 

98dango

Expedition Leader
I do know the o and 0 my cell phone hates me.

I feel it is actually some thing stupid simple. This truck died 2 months ago. I have about 2 months free time from work so its time to work on it.

Its amazing how time flys what I thought was a few weeks but its been 2 months.

My wife had not had any problems other than the speedo not always working right ( typical GM) and the transfer case motor working slowly and not always in low. On the day it shut off she had driving 6 miles to work it sat every thing was fine started home from work. She had made it about 2 miles when in her words its like you turned the key off. Motor shut off no brakes hydro boost she rolled to a stop called me. I got it to start but not run well. When it would run it had to be feathered to move. I got it on my empty car trailer that I had just in loaded and was taking home. There it got pushed off and sat till today. It started once but still ran poorly
 

82fb

Adventurer
My money would be on the crank sensor. But, I would clean all the grounds carefully, clean battery terminals, check condition of battery cables, check fuses and fuse block wiring first.
 

superbuickguy

Explorer
I'm with everyone else on this - you have a grounding problem.... check the main ones first - battery to engine, engine to body. To be certain, I'd run extra ground straps between the engine to body, body to frame, frame to battery (in addition to what's already there)

this is way out there, but the other thing I'd check is the positive leads to the starter.

Your comment about the t-case motor going slow actually points, again, to the body/engine ground strap
 

RAFoutdoors

Retired Explorer
I am just spit balling here and by no means do I have any technical skills or training but have you thought of the recent GM recall on the ignition switches shutting down because of weight on the keys (ring). I know they did not include the Tahoe but perhaps you have a bad ignition switch?
 

clandr1

Adventurer
I have an '05 Yukon trimmed out exactly the same, and (knock on wood) I haven't experienced this. It almost sounds like the vehicle is losing power and/or ground while driving based on what you describe

Have you tried removing the battery cables and inspecting/cleaning/tightening them?
 

98dango

Expedition Leader
Replaced the ground cable today no change. However I did find that it will start if I take it out of park still runs poorly but runs.
 

HenryJ

Expedition Leader
Lots of symptoms, some may or may not be related?

Do the fuel pressure - pump , injectors, and regulator checks. Fuel System Diagnosis , Testing fuel pump
Fuel pumps are a common failure. Be sure to use a OEM replacement (Delphi) pump only. There is a quality difference. Well worth investing in , or borrowing a gauge.

Make sure that the battery cables are indeed tight. Some of the bolts can be too long, or the hole not deep enough and they bottom out. This appears tight, but it is just the bolt that tightens, not against the cable. Hope that makes some sense.

Check the yellow wire a few inches from the throttle body where the harness makes a 90 degree turn.Early in 2000 some sub standard wiring was used. Fewer strands and less flexible. The wires tend to break internally creating shorts. Engine heat expands the insulation opening the break.
The engine sensing an interruption in the throttle position / sensor and pedal sensor communication defaults to limp mode.
I have seen this problem on a couple rigs in the fleet. The newest was a 2004.

I unwrap the harness and then gently pull on each wire looking for a section that pulls apart narrowing the insulation. If found, bare the wires, solder it together and cover with heat shrink. Problem solved :)

Good luck , hope you solve it.
 
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truck mechanic

Adventurer
Are there 2 pos. battery cables piggy backed? if so I bet the cable going to the under hood fuse panel has a bad conection or is corroded inside the jacket where you cant see it. I would try replacing it, for about $40 it mite be all it need, seen this more then once.
 

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