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GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15201
Experience:  GM Grand Master Technician 2007. 14 years experience.
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2003 chevy Tahoe cranks, attempts to start and does not. Key

Customer Question

2003 chevy Tahoe cranks, attempts to start and does not. Key on, fuel pump spools up, warning lights come on and go off, including Pass lock, gauges fluctuate. Roll key to the crank position, engine turns over and almost starts, release the key and is dies, hold the key and it just cranks.
Tried resetting pass lock, but the light is not flashing, so other than timing it, I have no idea if it is ready to relearn the resistor code.
Scanned it and it comes up with possible failure in the right front antilock brake circuit. Do not believe this is related to my no start problem.
Are the injectors tied to a common ground that could be open/ bad?
Submitted: 1 year ago.
Category: Chevy
Expert:  Chad Farhat replied 1 year ago.

Hi, I' m Chad. Welcome to JustAnswer. I' m reviewing your question now, and I will be post back with your reply ASAP

what is the mileage on it?

have you checked fuel pump pressure ?

so when you start no flashing security light ?

you could have a ignition switch problem(electrical part) if it is springing back and cut off power on fuel pump ?

do you have one or 2 keys ?

is there any prior work that was done that you think could have contributed to this problem ?

Can you check the fuel pump relay , it will be labeled (F/PMP ) in the fuse box under the hood ?

please let me know

Thank You
Chad Farhat
ASE Certified Technician

Customer: replied 1 year ago.
187000 I have not checked fuel pressure. the pump runs every time I turn the key to run. There is a mild fuel smell if I try this multiple times leading me to believe the injectors are being shut off as soon as the engine starts to run. Not sure if I have a 2nd key. The car is at my sister's and had sat for about a week while she was away. Prior to that it was running perfectly.
Customer: replied 1 year ago.
When I bought this vehicle about 4 years ago, I installed a remote starter and matched the pass lock resistor in a bypass circuit. Other than fighting with BCM over the door locks, it has performed flawlessly. Would this suppress the pass lock light from displaying if the module was in fault?
Customer: replied 1 year ago.
Should this throw a code?
Expert:  Chad Farhat replied 1 year ago.

I think this will suppress the light from displaying , the past 4 years is this first time this happened .

1- since you mentioned , check the grounds to the injector , stick a test light back probe the injector connector and see if you losing the ground from the pcm when it dies ?

2-we need spark & fuel to stay running , what are losing when it is dying can you check ?

3- what kind of scanner do you have ?

please let me know

Thank You
Chad Farhat
ASE Certified Technician

Customer: replied 1 year ago.
I have not verified the spark.
Are the injectors fired by supplying voltage, a ground, or both? I need to know in order to correctly interpret my light.
I have 2 scanners. An Autel MaxiScan . which appears to only communicate with ECM, and a CarMD 2100, which appears to communicate with the BCM as well since it pulled the ABS sensor status.
Neither came up with anything related to it not starting.
Expert:  Chad Farhat replied 1 year ago.

power from ignition switch and ground from computer for injectors connector .

Customer: replied 1 year ago.
Sorry., I did not see your reply until just now. I won't have a chance to check on this until this evening earliest, as It is stuck at my sisters across town.
So the computer supplies a momentary ground to the injector when the cylinder is on the intake stroke? Will a DMM react to this or should I use a test lamp or analogue meter?
Also, you never confirmed whether this should throw a code or not.
Expert:  Chad Farhat replied 1 year ago.

hey how are you

1- injectors you need both , they are supplied by power from switch and ground from pcm ,

if you hook up your test light lead to positive side of battery and back probe the injector connector one of the wires should make test light pulsate while it is running, so hook up ur light and crank and watch the moment it dies are you losing ground or try the other test lead on negative side of cable and check for power , or you are losing power when dying or both .

it should throw a light but if the computer is bad in it , it might not , you can go and see in the scanner under pending codes file if any exist but have not thrown the light yet ( we call them pending faults or codes )

i m online all weekend till 12 pm every night , so just let me know and we can go from there

Thank You


Customer: replied 1 year ago.
if the ECM is shutting the engine down, I loose the ground side. Power should be constant as long as the ignition is on. Is that correct?
Expert:  Chad Farhat replied 1 year ago.

yes you are correct

Expert:  Chad Farhat replied 1 year ago.

if you have 2 test lights hook one on each wire , just an idea