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Discussion Starter · #1 · (Edited)
I have a 2003 Chevy Suburban 2500 6L; went out on a 100 mile trip, which was 90% highway driving. About three bocks from home, the engine light came on while standing at a traffic light, and a message of reduced engine power. So I limped off into a Tim Hortons parking bay, plugged in my OBII scanner and recorded the error code, P1518.

Fine, I had this occur before, and had successfully erased it in the past. So I proceeded to do it again. As soon as the code was erased, it kicked back in. So I popped the the hood to cool the engine bay (this worked on previous occasions). Then tried to erase the trouble code, no luck. So I ended up limping back home.

I've read the numerous posts about this issue, though have not read about the following:
Where is the TAC located? Is it fixable or is it only replaceable like a light bulb? What would be the replacement part number?
 

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Discussion Starter · #2 ·
I may have isolated the problem. I checked my battery terminal connections and found them snug and clean. However, when I pealed the plastic protective boot I could see a gap between the wire tab and the battery. So I placed a steal washer in between as a spacer on both terminals. The Suburban started up instantly and the DTC code was erasable and it didn't reappear.:eek:
 

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TAC module is the entire throttle body. it is not servicable seperate from the throttle body. it unbolts from the manifold, uses about 4 bolts i believe, and a wire harness.

easy to replace, to diagnose it, you need a tech 2. if the correlation between the TPS and the throttle pedal are not correct, then it will go into limp mode. diagnosing it properly is where it will save you time and money. could also be a throttle pedal or wiring.
 

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Discussion Starter · #4 ·
Thanks for the feed back Triple-X. Temporarily, before replacing the TAC, I found a band aid solution; is too keep the hood ajar when driving - no recurring P1518. This leads me to believe their is inadequate cooling/ventilation at the top of the engine compartment.
 

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Thanks for the feed back Triple-X. Temporarily, before replacing the TAC, I found a band aid solution; is too keep the hood ajar when driving - no recurring P1518. This leads me to believe their is inadequate cooling/ventilation at the top of the engine compartment.
i wouldnt recommend doing that. not a good idea to drive around with the hood ajar.

if its not getting cooling properly, then maybe you can install a fan or possibly there may be a air circulation problem under the hood.
ive never ran into a problem like that before honestly. would be interesting to see if anyone has any ideas they would like to add to fix this problem
 

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No,tac Module Is Not The Entire Throttle Body,this Is The Tac Motor(connector With 8 Terminals.operation:tac Motor Is Used To Control Throttle Opening Instead Of Mechanical Linkage Of Cable.tac Motor Is Mounted On Throttle Body.tac(throttle Actuator Control) Module Is Located Left Rear Of Engine Compartment Mounted To Cowl Near Brake Booster Uses 2 Connectors C1 With 16 Pins & C2 With 8 Pins
 
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