05 cranks, starts, dies, no power locks, no windows - What the heck?

[05TahoeinLA]

My 05 Tahoe LS 2WD (4.8l) with 245K on the clock left me stranded at work the other day... Been a great vehicle otherwise.



Symptoms are:
1. Cranks strong - battery was replaced within the last year (Interstate)
2. Can hear fuel pump activate
3. Starts, stumbles, dies immediately
4. Key fob quit locking it a day or two prior to this
5. Power locks don't function on the door switches
6. Power windows don't work on the door switches
7. CEL has been on for more than 50K miles due to an emissions thing, but I haven't scanned for a new code yet (my bad)

Dash issues - maybe these are unrelated?
1. Oil pressure gauge used to read 160-200psi, mostly reads normal now
2. Tach was acting crazy a few weeks ago, now it seems normal
3. PRNDL screen is dim most of the time

Things I've done:
I swapped the fuel pump relay with the horn relay, horn and fuel pump both work with either relay.
Haven't found any blown fuses
Disconnected battery, touched terminals together for a couple hours, reconnected battery, no change, acts the same, cranks, starts, dies
Just in case, I put 3 gallons of gas in it after it wouldn't start.

I have a basic scan tool and a good multimeter. I don't have the Tech 2 scanner, but I'm not opposed to getting one.

Read that the BCM rarely fails, but might all this be BCM issues? Any pointers or advice appreciated!

 

[justirv]

My 05 Tahoe LS 2WD (4.8l) with 245K on the clock left me stranded at work the other day... Been a great vehicle otherwise.



Symptoms are:
1. Cranks strong - battery was replaced within the last year (Interstate)
2. Can hear fuel pump activate
3. Starts, stumbles, dies immediately
4. Key fob quit locking it a day or two prior to this
5. Power locks don't function on the door switches
6. Power windows don't work on the door switches
7. CEL has been on for more than 50K miles due to an emissions thing, but I haven't scanned for a new code yet (my bad)

Dash issues - maybe these are unrelated?
1. Oil pressure gauge used to read 160-200psi, mostly reads normal now
2. Tach was acting crazy a few weeks ago, now it seems normal
3. PRNDL screen is dim most of the time

Things I've done:
I swapped the fuel pump relay with the horn relay, horn and fuel pump both work with either relay.
Haven't found any blown fuses
Disconnected battery, touched terminals together for a couple hours, reconnected battery, no change, acts the same, cranks, starts, dies
Just in case, I put 3 gallons of gas in it after it wouldn't start.

I have a basic scan tool and a good multimeter. I don't have the Tech 2 scanner, but I'm not opposed to getting one.

Read that the BCM rarely fails, but might all this be BCM issues? Any pointers or advice appreciated!

I'd verify fuel pressure at the rail, then spark. The fob, door locks, and windows may be interrelated, and along with the dash, may be power/ground related.

 

[S33k3r]

I'd check the wiring leading to your ECU. We had a very similar symptoms and it turned out to be some severely rusted and some rusted through wires at the ECU. The mechanic permanently fixed it by cutting a wiring harness from another truck and patching it in. It's gone 10-20k since the fix and THAT issue has not resurfaced.

 

[Fless]

Dash issues - maybe these are unrelated?
1. Oil pressure gauge used to read 160-200psi, mostly reads normal now

Let's see a pic of that non-standard oil pressure gauge. Every one I've seen tops off at 80 psi, and that's when the sender is defective or the circuit is open.

 

[05TahoeinLA]

Let's see a pic of that non-standard oil pressure gauge. Every one I've seen tops off at 80 psi, and that's when the sender is defective or the circuit is open.

Standard gauge. Just implying that it was reading where 160-200 psi would be.

I did change the sending unit. And the gauge still acted crazy. After 6-8 months. It fixed itself.

 

[Fless]

Standard gauge. Just implying that it was reading where 160-200 psi would be.

I did change the sending unit. And the gauge still acted crazy. After 6-8 months. It fixed itself.

Probably a bad stepper motor for the gauge.