2003 Z71 P1516 Fault: Has History
December 23rd, 2014, 3:17 AM
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2003 Z71 P1516 Fault: Has History
Hello everyone. I have a 2003 Avalanche 1500 Z71 5.3 and I was wondering if anyone here had the same problem I am having. I had this problem back in July 2014 and after some parts changed it is back again 5 months later. I’m sorry if this topic has been covered before I really did search for an answer but I couldn’t find anything specific for my year/model/engine type. I know it’s a long read but I like to be really detailed and appreciate you taking the time to read through it. I am a Mechanic (jet-engine) so don’t be afraid to get too technical with your responses lol. I’ve had the truck for 5 years now so this is my first major issue at 150,000 miles.
Fault: Engine Reduced Power w/ P1516 Code (has history see below)
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Current Symptoms:
Engine loses all acceleration, unable to increase in speed and no pedal movement recognized by tachometer. When engine is idling at 0mph, rough and shaky idle occurs until engine shutdown and restart. Check Engine Light (CEL) is present at restart. Engine idles normally after restart with CEL on. No reduced engine power message is shown after restart, CEL is still present and truck will accelerate normally up to 30mph, after 30mph reduced engine power message appears and acceleration loss / hesitating idle return. CEL can be cleared w/ ODB2 scan tool, once clear truck will operate normally from 0-70 mph. So far,the fault has only happened at a continuous speed.
Parameters that caused fault:
-Incident 1: Driving at a steady speed of 55 mph for approximately 15 minutes.
-Incident 2: Driving at a steady speed (with cruise control on) at 70mph for 30 minutes.
-Incident 3: Driving at a steady speed of 50 mph and attempting to accelerate to pass another slower vehicle.
During all 3 incidents: No oil pressure, battery voltage, or coolant temperature fluctuation.
NOTE: All 3 incidents occurred within the same week, (on my way to and from work). I have calculated the distance between each point that I broke down, and it seems that all 3 spots are approximately 50 miles apart from each other. I'm not sure if the override commands to clear the fault with the ODB2 tool only lasts for “x” amount of time, or if this is just a coincidence.
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Previous History:
July 2014: Same as above except truck would fault at any acceleration, not just at a continuous acceleration. Sometimes it would occur immediately after I put it in (D) Drive and began to pull out from my driveway, other times it would happen at a Red to Green Light changeover after driving for some time.
Troubleshooting that corrected the issue:
- Removed and replaced air filter
- Removed and cleaned Mass Air Flow Sensor, reinstalled
- Cleaned Throttle Body Actuator butterfly valve
- Checked the pigtail connector on the Throttle Body Actuator (TBA) and the pin-retention looked ok.
- Removed and replaced TBA unit assembly
After performing the above in July, this fixed the problem, but now 5 months later I am having the same fault and code P1516. I am wondering if I perhaps got a malfunctioning TBA unit. Going to return the TBA and exchange it for another one to see if the problem or symptoms change. Is there anything else I should check for in addition to doing this? I read online that there are grounding points in the truck that sometimes get corroded or frayed that can induce this problem; does anyone know the location of these? Also, could a failing battery or alternator induce this problem? I was thinking maybe during an electrical spike it would shutdown, battery is 5+ years old and alternator is original. What other parameters can cause a reduced engine power message?
Fault: Engine Reduced Power w/ P1516 Code (has history see below)
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Current Symptoms:
Engine loses all acceleration, unable to increase in speed and no pedal movement recognized by tachometer. When engine is idling at 0mph, rough and shaky idle occurs until engine shutdown and restart. Check Engine Light (CEL) is present at restart. Engine idles normally after restart with CEL on. No reduced engine power message is shown after restart, CEL is still present and truck will accelerate normally up to 30mph, after 30mph reduced engine power message appears and acceleration loss / hesitating idle return. CEL can be cleared w/ ODB2 scan tool, once clear truck will operate normally from 0-70 mph. So far,the fault has only happened at a continuous speed.
Parameters that caused fault:
-Incident 1: Driving at a steady speed of 55 mph for approximately 15 minutes.
-Incident 2: Driving at a steady speed (with cruise control on) at 70mph for 30 minutes.
-Incident 3: Driving at a steady speed of 50 mph and attempting to accelerate to pass another slower vehicle.
During all 3 incidents: No oil pressure, battery voltage, or coolant temperature fluctuation.
NOTE: All 3 incidents occurred within the same week, (on my way to and from work). I have calculated the distance between each point that I broke down, and it seems that all 3 spots are approximately 50 miles apart from each other. I'm not sure if the override commands to clear the fault with the ODB2 tool only lasts for “x” amount of time, or if this is just a coincidence.
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<!--[endif]--><o
</oPrevious History:
July 2014: Same as above except truck would fault at any acceleration, not just at a continuous acceleration. Sometimes it would occur immediately after I put it in (D) Drive and began to pull out from my driveway, other times it would happen at a Red to Green Light changeover after driving for some time.
Troubleshooting that corrected the issue:
- Removed and replaced air filter
- Removed and cleaned Mass Air Flow Sensor, reinstalled
- Cleaned Throttle Body Actuator butterfly valve
- Checked the pigtail connector on the Throttle Body Actuator (TBA) and the pin-retention looked ok.
- Removed and replaced TBA unit assembly
After performing the above in July, this fixed the problem, but now 5 months later I am having the same fault and code P1516. I am wondering if I perhaps got a malfunctioning TBA unit. Going to return the TBA and exchange it for another one to see if the problem or symptoms change. Is there anything else I should check for in addition to doing this? I read online that there are grounding points in the truck that sometimes get corroded or frayed that can induce this problem; does anyone know the location of these? Also, could a failing battery or alternator induce this problem? I was thinking maybe during an electrical spike it would shutdown, battery is 5+ years old and alternator is original. What other parameters can cause a reduced engine power message?
Last edited by Defcon 1; December 23rd, 2014 at 4:30 AM.
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