Topic says it all - any ideas??

 

DTC P1514 Throttle Body Performance
Circuit Description
The PCM uses the TP, the BARO, the IAT and the engine RPM in order to calculate an expected Mass Airflow rate. The PCM compares this value to the Mass Airflow value and the speed density calculation in order to verify the proper throttle operation.

Conditions for Running the DTC
DTCs P0601, P0602, P0606, P1515, P1516, P1517, P1518, P1624 are not set.
DTCs P1120, P1220 and P1221 are not set at the same time or DTCs P1120 and P1220 are not set at the same time.
Engine operates longer than 1 second.
Engine speed is greater than 500 RPM.
Conditions for Setting the DTC
The PCM detects that actual airflow (MAF) and Speed Density is much greater than the expected (calculated) airflow rate.
All above conditions met for less than 1 second.
Action Taken When the DTC Sets
The PCM will illuminate the Malfunction Indicator Light (MIL) when this diagnostic runs and fails.
The Reduced Engine Power message displays on the drivers information center.
The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Freeze Frame and/or Failure Records.
If no other TAC System DTCs are set, the TAC System operates in Reduced Engine Power mode, and this DTC will be stored. If certain TAC System DTCs are set at the same time, the TAC System either defaults to a more tightly restricted mode of operation if the TAC determines that limited safe operation is possible, or the TAC commands the engine to shut down.
Conditions for Clearing the MIL/DTC
The PCM turns the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.
A last test failed (Current DTC) will clear when the diagnostic runs and does not fail.
A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
The PCM battery voltage is interrupted.

Important
The clear DTC info function may have to be performed twice in order to clear a Throttle Actuator Control System DTC.


Clear the MIL/DTC information using a scan tool.

 

Bowtiebandit's explanation is precise. What will CAUSE all this (amongst some other things) is if you tweaked your LS1Edit MAF table too much or if you have a MAF-translator and you adjusted that too much. This will throw off the calculated airflow reference to the 'actual (tweaked)' airflow of the MAF frequency. I've thrown this code many times in my earlier days of playing with MAFT or when i finally graduated to Edit, i did play wiht MAF tables in beginning and threw this code and went to Reduced Power/Limp mode. I no longer Adjust the MAF tables from default any more. IMO the MAF table should not even exist. Should be left to default.

IF you did not cause this code due to MAF table or MAFT adjustments, then look into seeing what is wrong with the maf itself. It may be dirty, especially if you're using an aftermarket cleanable air filter and any of the screen cleaner or goop you spray on it gets onto the MAF sensors. I have thrown the 1514 code and it was a dirty maf. Take maf off and VERY CAREFULLY with a q-tip and some isopropyl aclohol from your medicine cabinet clean off the 3 sensors and the rails they are attached between. you'll be surprised to see the dirt you get off. the dirtier the sensors, the less the airflow will be seen/measured which will cause car to run lean and/or eventually throw the 1514Calc code if the 'actual' measured flow gets too far off the calculated algorithms for expected flow.

Good luck!!


[Modified by rwj383, 8:34 PM 5/11/2003]

 

I used to get the 1514 and reduced power all the time when I was trying different maf and TBs. I now have stock ones, but still get the reduced power at the track during burn outs about 50% of the time. The car runs OK other than that. I can tell you that is the longest 10 seconds pulling the key and waiting to start it back up. Any ideas on the cure for this. Also it seems to do it more often in 2nd gear burn outs. :confused:

 

The code will happen all the time with blower cars that force ait into the maf if not scaled properly with LS1 Edit. its a very easy fix.

 

Tom, I believe Chris is talking about the P1514 table in LS1-Edit that lets you redefine what the expected flow rates are. FI guys need this. :)

Try to make it look like you're just icing the other guy when you're sitting there waiting. :jester

 

I don't have FI. Could I just shut the code off in edit or would it still shut down the engine and just not show the code? I have always had this problem at times, even with the stock engine. I guess it's another 97 Glitch :confused:

 

Well, you do have lots of cubes and nitrous, the problem is the same. You're drawing more air through the MAF than expected and throw the code. There's a lot of sanity checking like this going on, remember it is electronic throttle control. The right thing to do is to adjust the expected flow in the P1514 diagnostic table rather than simply disabling the code. I don't know that that would be adequate anyway, the FI guys screamed bloody murder until the feature was added to LS1-Edit. :D The table is in the diagnostics section.

 

I'm not running Nitrous right now and I wouldn't be spraying during a burn out, at least not anymore. I see the table in edit for the 1514, but don't know what to do with it. Any help? Thanks.