p1518

[tomloans]

2003 Tahoe 5.3 with about 230k miles...All right folks. I have a p1518 code and after I erase it I just turned the key without starting and it'll hit me again it comes with the reduced engine mode. This is a new one for me after 22 years of owning this car. Any feedback would be great. Thank you

 

[Fless]

Tell us what you're working on -- year, make, model, engine, etc. Consider putting that in your signature so it's always there.

Sounds like a TAC module/wiring issue, but I'll let others chime in once we know the vehicle.

 

[tomloans]

Tell us what you're working on -- year, make, model, engine, etc. Consider putting that in your signature so it's always there.

Sounds like a TAC module/wiring issue, but I'll let others chime in once we know the vehicle.

2003 Tahoe 5.3 with about 230k miles... thank you. Bought new

 

[Fless]

See if @rockola1971 has any more to add than what is in this post:

Weird misfire in 2004 chevy tahoe

I have bought a 2004 chevy tahoe and it has missfire. I have changed all spark plugs, spark plug wires, O2 sensors, and knock sensors with their wire. I also cleaned the MAF sensor, throttle, intake manifold, and intake manifold sensor. All of my Injectors were tested and they work. What could...

www.tahoeyukonforum.com

 

[tomloans]

I have already changed out the harness many years ago. This is an odd code to get all by itself. And it seems severe. I literally just turn the key to the on position without starting the engine and the code and reduced engine power came back.

 

[Fless]

Are you talking about the connection at the TAC, or at the throttle body?

 

[tomloans]

Are you talking about the connection at the TAC, or at the throttle body?

Throttle body only. I had a new spare TBS and I just changed out the throttle sensor ( only ) and it did nothing. I sprayed some cleaner into the throttle body and it is clean and smoothly operating. It was already relatively clean.

Here are the updated symptoms. Very weird. I erase codes. Then I turn the key to the on position with no cranking, the p1518 code comes up with reduced engine mode before I even start the engine. If I continue to start from that position, then all hell breaks loose. (LOL) I get the P1516, P1518, and P2108 codes along with the reduced engine as well. I really think this more to do with the TAC or some short thereof. I love this truck with this one exception. Sure wish we can go back to fly by wire.

 

[tomloans]

Are you talking about the connection at the TAC, or at the throttle body?

One other thing, my long term trims are rather high. 5.5 at idle and 8.0 in drive and stopped. Short term fluctuates by hovers around zero to negative 1 to positive one.

 

[rockola1971]

Get your step stool out and prepare to have a sore back. Your engine to firewall braided ground is broken/loose/corroded. Clean both ends at the block and at the firewall stud with a wire brush. Be sure to give the ring terminals on the end of the braided ground a good cleaning too. Dont be surprised if the braided ground is corroded in half and needs replaced.

 

[Fless]

FWIW drive by wire is the electronic throttle system. Drive by cable is the physical throttle cable system.