2017 LT Tahoe 5.3 Randomly Starting

[Trkr-ma]

So my Tahoe has been acting up the last few months. I had to starter replaced and a relay. I drive semi so the mechanic at the shop that works on semis did the work. I asked him to scan it right out the gate, he didn't. I think because I'm female and I don't know what I'm talking about.
( Supposedly ) So I may have had put in a new starter and didn't need it. I never saw it, didn't see if the connectors were fried like most stated on here. I didn't ask him if he tested it, I just assumed he did. Then it acted up again. So he changed the relay out. Which relay, I have no idea. I have yet to ask him. As I later found out there are several relays. Then a guy that works with my neighbor said it could be the selector, so is that the shifting selector? I'm stumped! I was out of work for a couple of months, so money was the issue or I would have taken it to the dealer and just got it done with.

 

[Fless]

Can you describe the symptoms in more detail? By "not starting" do you mean that the engine doesn't crank (turn over), or that it cranks but doesn't fire up and run?

 

[Trkr-ma]

All the dash lights and gauges work. When I push start it will just very quietly click. Before I had starter replaced, I could put in neutral and it would start. I tried this time and it won't. Sometimes I could start it remotely when it wouldn't start by a regular start up.

 

[Trkr-ma]

I just want to add, the brake sensor has been recalled and repaired long before this issue. I bring that up, because a few people had issues with that.

 

[persistent]

All the dash lights and gauges work. When I push start it will just very quietly click. Before I had starter replaced, I could put in neutral and it would start. I tried this time and it won't. Sometimes I could start it remotely when it wouldn't start by a regular start up.

i assume you don't see a battery icon when you attempt to start the engine and it fails.

without some indicator that the battery is low, the fact that it powers up suggests your battery is ok. the best way to test the battery is a simple battery tester, e.g. ancel BA101 tester.

if the battery is good and you don't hear the starter attempting to start the engine, i would immediately look at the starter. it's also a good idea to get a cheap bidirectional scan tool, so you can cut out the middleman for diagnostic info.

 

[Geotrash]

From your description, it sounds like the starter relay is clicking closed, which is helpful.

Here’s how the system works:

When the Ignition mode switch is placed in the crank position, a discrete signal is supplied to the body control module (BCM) notifying it that the ignition is in the crank position. The BCM then sends a serial data message to the engine control module (ECM) that crank has been requested. The ECM then verifies that the brake pedal is applied and that the automatic transmission selector is in Park/Neutral. If it is, the ECM then supplies 12 V to the control circuit of the starter relay. When this occurs, battery positive voltage is supplied through the switch side of the crank relay to the S terminal of the starter solenoid.

Here is the testing procedure if you have a meter:

1. Verify that a test lamp illuminates between the M64 Starter Motor B+ terminal 1 X2 or A X2 and ground.
   • If the test lamp does not illuminate and the circuit fuse is good
   • Ignition OFF.
   • Test for less than 2 Ω in the B+ circuit end to end.
     • If 2 Ω or greater, repair the open/high resistance in the circuit.
     • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
   1. If the test lamp does not illuminate and the circuit fuse is open
   • Ignition OFF.
   • Test for greater than 100 Ω between the B+ circuit and ground.
     • If 100 Ω or less, repair the short to ground on the circuit.
     • If greater than 100 Ω, replace the M64 Starter Motor.
   1. If the test lamp illuminates
2. Test for less than 0.5 V between the positive battery post and terminal 1 X2 or A X2 at the M64 Starter Motor with the ignition in the START position.
   • If 0.5 V or greater
     Replace the positive battery cable.
   • If less than 0.5 V
3. Test for less than 0.5 V between the negative battery post and the M64 Starter Motor case with the ignition in the START position.
   • If 0.5 V or greater
     Replace the negative battery cable.
   • less than 0.5 V
4. Replace the M64 Starter Motor.