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AMEDEE
AMEDEE, CHEVY TECHNICIAN
Category: Chevy
Satisfied Customers: 26645
Experience:  ASE certified tech ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
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O4 impala no start after sign lock cal replaced and re learn

Customer Question

o4 impala no start after sign lock cal replaced and re learn procedure done multiple times
Submitted: 5 months ago.
Category: Chevy
Expert:  AMEDEE replied 5 months ago.

Hello and welcome!

My name isCustomerand I can assist you with your question.

Expert:  AMEDEE replied 5 months ago.

I am very sorry your having this issue with your vehicle.

I will try my best to answer all of your questions.

However, before we get started, please let me mention a few things.

1. If at any point you would like to speak on the phone, please feel free to request a phone call on your end and I can call you right away.

2. If you dont understand any technical terms or anything that I mention (component tests or theory or operation), please let me know and I will provide you with a more in debt explanation or answer.

3. Please understand that I am here to help you any way I can.

Expert:  AMEDEE replied 5 months ago.

Can I start by getting your VIN and any stored codes in the computer?

Thank you!

Customer: replied 5 months ago.
no codes. 2G1WF52E749385981. I am an experienced tech as well and I've done this repair several times never had this issue been cranking the thing down the relearn so much the starter is frying out. now I'm just frustrated. I've got fuel volume and pressure got spark. cranks but no injector pulse so it seems if its the lock cylinder (new @ auto zone)may be bad. can't see the computer burning out but you never know. this car always ran great what am I missing. no wiring issues everything connected properly. so hope that helps you help me. thank you so much. Alex
Expert:  AMEDEE replied 5 months ago.

Thank you for that information Alex.

It would be best to speak over the phone. I can lower the cost of the phone call down to 5 bucks in order to better help you. I can speak on the phone right now and follow up phone calls are free.

Expert:  AMEDEE replied 5 months ago.

Does that sound fair?

Customer: replied 5 months ago.
I meant doing relearn
Expert:  AMEDEE replied 5 months ago.

got it

Customer: replied 5 months ago.
can't now this is gonna have to work
Expert:  AMEDEE replied 5 months ago.

ok

Expert:  AMEDEE replied 5 months ago.

So is the anti theft light on or flashing with the key on or when cranking it over?

Customer: replied 5 months ago.
key on
Expert:  AMEDEE replied 5 months ago.

So your saying there is a security light with the key on correct?

Expert:  AMEDEE replied 5 months ago.

SO the security light is on but there are no stored codes in the computer?

Did you check the BCM for codes?

Customer: replied 5 months ago.
batt-sec-batt-sec. I did check the body mod. no codes no codes none pcm bcm I did clear it but really there was nothing there to clear. I suppose no readiness monitors have run cause it hasn't started since I "fixed" it is there a test for the lock cylinder. and everything seems ok when I hook it up to a scan tool so I really can't suspect its brain ya know. this sucks I can tell ya that I'm all out of ideas at the moment
Expert:  AMEDEE replied 5 months ago.

If the vehicle is not starting due to the security system, there should be a stored code in the computer related to this.

Customer: replied 5 months ago.
I just started the procedure yet again almost time to try an start after the initial 10 minute wait. all the times I've tried the security light has not gone off and stayed off. yes there should b a code. again, do you know of a test to determine if the chip on the cylinder is good. or if the resistance in the key is good. the reason I changed the lock was mechanical failure of the cylinder how can I just condemn a $120 part without having tested it
Customer: replied 5 months ago.
its getting late n I'm packing it in for now but I expect to be able to get ahold of you to continue tomorrow as there has been no prescribed course of action to take. so thanks for now I ll leave my Mac on so it.ll let me know if you reply tonight. again thanks Alex
Expert:  AMEDEE replied 5 months ago.

YES, it sure sounds like a failed passlock sensor.

When testing the inputs to the sensor,

With your voltmeter, check the voltage from the Black wire to the White wire, backprobing with the sensor connected. It should have 9.0 V or higher at: IGN 0, IGN 1 and CRANK.

Then test voltage on the Yellow signal wire and it should have 4.7-5.0 V at: IGN 0, and then a drop to a specific value should occur as the key is rotated to IGN 1 and/or CRANK.

If all inputs check out ok, this leaves a faulty passlock sensor.

Expert:  AMEDEE replied 5 months ago.

Hello there!

I am just checking in to see how things are going and to see if you need any further assistance?

If so, please let me know as I will be happy to help.

Best Regards,

Customer/p>