07 Avalanche - TechMate Code 81 Throttle Actualtor Control Fault

[jimzonaboat 1]

Last trip of the season my Avalanche went into power reduction mode. I was cruising around and then backed off the throttle at which point I got the buzzer every minute and no throttle. I turned the boat and batteries off for about a minute and then back on and the throttle operated normally for the rest of the day.

 

My engine information is:

Year: 2006
Make: PCM Excalibur 330
Model: 15-570V-01 (5.7L 350 CID LH MPI) (GM)
Serial #: 462755
Firing Order: 18436572
Manuf: 6/21/2006

 

I went ahead and bit the bullet and got the TechMate Scan tool from Rinda Technologies to see what was going on under the hood. This is the information it provided:

Code 81

Throttle Actuator Control (TAC) Fault

TAC Error, PPS 1&2 Correlation Fault

TAC Error, Limited Authority

 

In the PCM Digital Throttle Control Diagnostic Supplement (attached if anyone needs it) it lists a variety of combinations, but this exact combination isn't mentioned. Anyone experience this and what the fix was? This happened last year as well and the shop replaced the Throttle Position Sensor on the Throttle Body.

Digital Throtle Control Supplement.pdf

[mancho 85]

WOW! Interesting. I wish you lived near me, I would love to borrow that scanner ;D

 

I found the codes to be related to a few that they point out in the table, but most interesting, is that water intrusion and connections play a big part of this working. Have you tried to disconnect and inspect for moisture, corroded contacts and loose wires? I am not an expert at this but this stuff always interesting.

 

From the PDF:

Inspect DTC related connectors for signs of water intrusion. When this occurs, multiple trouble codes could be set with no circuit or component conditions found during diagnostic testing.

• When the TAC module detects a condition within the TAC system, more than one TAC system related trouble code may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual condition may correct more than one trouble code. Disconnecting components during testing may set additional trouble codes.

[jimzonaboat 1]

Yea that's going to be my first step to look at all the connections. I'll let it sit for the moment though since the cover is on the boat and it's in my neighbors driveway...at least until my nice new boat garage is finally finished

[jimzonaboat 1]

Just an update for anyone tracking this thread. So far this season I have only had this trouble code pop up one time (actually twice in the same day to be specific). I was easily able to reset the ECM with the TechMate Scan tool. I started keeping that on the boat just in case.

 

When I got the boat back home, I reseated all of the connections: 2 at the ECM, 1 at the Pedal Position Sensor (where the throttle links to), and 1 at the Throttle Body/Air Intake.

 

So far it hasn't acted up again this year. Hopefully that's all it took was to reseat the connections...fingers crossed!