2007 Tahoe LTZ Issues need help

[zharrison]

I'm sorry if this has been covered, I just don't how to type it in the search bar.

2007 LTZ, bought used in 2016 with 90ish thousand on it. Everything was fine for along time. At 220,000 the oil pump went. Bought one of those reman motors online (don't remember who) it lasted until 240,000 miles so only 20k on the new motor. Lifter went out and ate the cam. I rebuild the top end. DOD delete and all, got all the parts from Texas Speed. Fast forward a few thousand miles and the transmission went out. Trailed it to a builder and had it completely rebuild with the corvette servo and so forth. Ran great, fun to drive. Then the Limp mode would kick on now and again, overheat, and the lights go on. A little research and I replaced the throttle body position sensor (Cheap rebuild one from O'Reilly's). Fix all those issues.

Currently at 283,000 and now yet again, It randomly goes into Limp mode, will crank and not start randomly, it will randomly die (noticed on small hill/bump), will just click and not crank then turn the key off and on again and it will crank and start. CEL is very hit and mis. I'm charging up my scanner to see if there are any codes or stored codes and I will add them as I get that info.

I need ideas of what to look at, the Wife is irritated with as it is hers and she loves the dang thing and if I do not fix it she will force me to buy her a new car and it is not in the budget.

Thread links would be awesome.

Thanks

 

[Fless]

Start by looking at the battery cables; pull the connections, clean them, and retighten. Do a voltage drop test to verify that they can handle the load.

 

[zharrison]

I did relocate the battery to the left side and redid the power and grounds with 4/0 copper. I was doing an audio install at one time but will all the issues never got past moving the battery and doing the power and ground cables.

 

[rdezs]

I would start with having the battery load tested. These things need a battery in top condition. Most auto parts stores will test it on the vehicle for free. Make sure your battery and charging system are operating 100% before moving on. If the battery doesn't hold 12.6 volts overnight, time for a new one.

As Fless mentioned, even if you did the cables recently, check and clean all connections.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

 

[zharrison]

i get 1mV or less testing between the ground post and terminal. 0 from the terminal to the firewall and 0 from the firewall to the motor.

When I get back from the store i will pull codes.

 

[Fless]

i get 1mV or less testing between the ground post and terminal. 0 from the terminal to the firewall and 0 from the firewall to the motor.

When I get back from the store i will pull codes.

While cranking? Have to put a big load on the circuit.

 

[zharrison]

I did start it, ill check it again.

Hooked up the launch scanner and got

TCM - U0073-00
Seat Module - B2365-069 and B1925-05
Rollover sensor - B1011-71
Electronic brake control - C0899-00 and C0900-00 (Low and High Voltage)

 

[j91z28d1]

I wouldn't be supised if the tb you got from the auto parts store when bad pretty quickly.


but yeah, you gotta test those voltage drop while cranking. not just as rest

 

[Fless]

After confirming that the main power and ground cables are solid, look at the freeze frame data for each one of those codes; viewing each parameter might show you what the issue is, then you can go for the cause.

The link below has info on diagnosing the C0899 code. Might walk through the checks to see if something is compromised. When testing powers and grounds at the EBCM (without the EBCM connected), use a heavy test light, one that draws several amps. That will tell you if the circuit can handle the load.

C0899 — 2007 Chevrolet Tahoe 2WD V8-5.3L Service Manual | Operation CHARM

Detailed repair manual for the 2007 Chevrolet Tahoe 2WD V8-5.3L.

charm.li

 

[zharrison]

No diagnosing it today, the wife decided to drive it to work. Ill try again tomorrow. Thanks for all of the help so far.

 

[swathdiver]

Hooked up the launch scanner and got

TCM - U0073-00
Seat Module - B2365-069 and B1925-05
Rollover sensor - B1011-71
Electronic brake control - C0899-00 and C0900-00 (Low and High Voltage)

How do you know that code U0073 is associated with your TCM?

Can you tell if these U and C codes are Active or Historical?

 

[zharrison]

How do you know that code U0073 is associated with your TCM?

Can you tell if these U and C codes are Active or Historical?

It was in the TCM section of the scanner. Active. I erase them and they come back.

 

[swathdiver]

It was in the TCM section of the scanner. Active. I erase them and they come back.

But no P0700?

Still getting those two "C" codes? Battery is good right? Whenever we see lots of codes from different modules we suspect a voltage problem due to a weak battery or corroded grounds/cables.

Anyhow, this (U0073) is a Canbus issue, the tan (2500) and black and tan (2501) data lines that run through all modules so they can talk to each other.

GM has a program on the ACDelco TDS website that you can use (with subscription) for diagnosis with a laptop and MDI/MDI2 that helps isolate the source.

South Main Auto on YouTube also shows how to isolate CanBus communication line problems.

Last week I got the U0073 and P0700 on mine. Cleared codes to get home and hasn't come back. It's either a bad TECHM or chafed wires going to the transmission.