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Pete
Pete, Auto Service Technician
Category: Chevy
Satisfied Customers: 26713
Experience:  14 years GM dealer Technician.
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My chevy Silverado 2500 HD fires off for a second or so and

Customer Question

my chevy Silverado 2500 HD fires off for a second or so and stops. fuel pressure at engine is 60 lbs. fully charged battery
JA: How many miles are on the vehicle? And when was it last serviced?
Customer: 126,000 mi. serviced about a yr. ago with tune up and ecm tune for better gas milage
JA: What year is your Silverado?
Customer: 2004
JA: Are you fixing your Silverado yourself? What have you tried so far?
Customer: trying to fix it. checked fuses and relays, replaced fuel pump relay, checked fuel pressure at engine [ 60 lbs.], tried to check code for check engine light that was showing before the problem started, but scanner showed no communication with computer
JA: Anything else you want the mechanic to know before I connect you?
Customer: the battery is about I yr. old, but after sitting for a week was completely dead and seemed hard to charge.
Submitted: 7 months ago.
Category: Chevy
Expert:  Pete replied 7 months ago.

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

Is the security/theft light flashing or staying lit on the dash after the truck starts and stalls without turning off the key?It may look like a picture of a car with a lock across it.

Let me know so we can continue,thanks Pete

Customer: replied 7 months ago.
sometimes it goes off immediatley, and sometimes it stays on for e second or less
Expert:  Pete replied 7 months ago.

Try this procedure below so we can see if all that is needed is a key relearn and let me know if it works.You want to make sure you have a fully charged battery to perform this here and if a step is missed the procedure will need restarted.

30 MINUTE LEARN PROCEDURE
1. Turn ON the ignition, with the engine OFF.
2. Attempt to start the engine, then release the key to ON; the vehicle will not start.
3. Observe the SECURITY telltale; after approximately 10 minutes the telltale will turn OFF.
4. Turn OFF the ignition, and wait 5 seconds.
5. Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes; the vehicle is now ready to relearn the Passlock Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK.

IMPORTANT: The vehicle learns the Passlock Sensor Data Code and/or password ***** the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.

6. Start the engine.

If this does not work let me know so we can continue.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service,your 5 star rating is appreciated.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 7 months ago.
is the security taletell the light with the car & lock symbol?
Expert:  Pete replied 7 months ago.

Yes that is the light

Customer: replied 7 months ago.
hello, is anyone there?
Expert:  Pete replied 7 months ago.

Did you get my last reply?I posted that yes this is the light.

Let me know,thanks Pete

Customer: replied 7 months ago.
tried key relearn twice but still does not start
Customer: replied 7 months ago.
tried key relearn twice, still did not start. the telltale light was not on during the procedure.
Expert:  Pete replied 7 months ago.

O.k.,then this isnt a theft/security fault here.

Has your scan tool you are using been able to communicate with the computer in the past?

Let me know so we can continue,thanks Pete

Customer: replied 7 months ago.
a friend used his scanner and it said no communication with ecm
Expert:  Pete replied 7 months ago.

O.k.,if this was a scan tool that has communication capabilities with this model (as most can) and there is no communication with the ecm there is a chance the ecm has failed internally needing replaced.It looks like you had an ecm tune done.This is usually done with an after market programmer to change the programming in the ecm.If the programming has been lost or wiped out due to an ecm fault internally this will cause this as well.

Can you tell me what liter engine is in your model here so I can look at some fuses and let you know what to check for fuses for the ecm?

Let me know,thanks Pete

Customer: replied 7 months ago.
the inspection certificate says it is a 6000, and i have been told it was a 6 L
Expert:  Pete replied 7 months ago.

O.k.,check these fuses and make sure they are o.k.:

Instrument panel fuse block (inside vehicle)

IGN 0 (10 amp)

Under hood fuse block

Crank fuse (10 amp)

PCM 1 fuse (15 amp)

PCM B fuse (20 amp)

If these fuses are all o.k. check the wiring and connections at the PCM.If there are any issues with the wiring or connections this will need resolved.If all wiring and connections are o.k the power and ground wires will need tested for proper power and ground at the PCM and if these are o.k. I suspect the PCM is at fault needing replaced.

Let me know if you need anything else and feel free to rate my help here as this is how I receive credit for my time.Your 5 star rating is appreciated

Thanks Pete

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