My car runs great but i can not go WOT without it going into limp mode or REDUCED ENGINE POWER. It keeps setting off an active handling code as well.


My codes on my DIC are listed

P1515H
p0300h

Tcs:
c1286hc
c1226h
c1278h

U1096h
u1064h
u1016h

B2262H

I have reset these several times and they all come back so im sure they are legit codes to an extent.

 

Anyone?

 

TTT

 

These are the descriptions of the codes in the TCS module.
C1286 Steering Sensor Bias Malfunction
C1226 LF Excessive Wheel Speed Variation
C1278 TCS Temporarily Inhibited By PCM

This is from the PCM
P1515 Command vs Actual Throttle Position Performance (PCM Module)
P0300 Engine Misfire Detected

This is from the BCM
U1016 Loss of Communications with PCM
U1096 Loss of Communications with IPC

This is from the IPC
U1064 Loss of Communications with BCM

Looks like something may be disconnected or loose. Hope this helps.

 

These codes are not thrown as long as i just drive the car easy. As soon as i punch the throttle and go WOT, My cluster looks like one of those flashing christmas light structures. check engine light, reduced engine speed, traction control, abs. you name it!

 

Just a thought...did you happen to change tires or wheels and get the wrong size up front? Not trying to call you out on anything but just wondering.

 

OEM wheels and tires. I am about to go larger though. about to put 18's in the front and 19's in the rear but havent even ordered them yet. I did put 3.42 gears in the car but my tuner added that into the computer. I had torque management deleted out as well.

 

P1515 Commanded vs Actual Throttle Position Performance

This is what is generating your REDUCED POWER mode. The throttle plate is driven by a motor, and there is a sensor that reports throttle position. The commanded position (for example, WOT) and the sensed position, do not agree. Check the wiring to your throttle position sensor.

P0300 Engine Misfire Detected

Bad spark plug, bad or loose spark plug wire, bad fuel injector .... the PCM is sensing (by watching the rotational speed of the crankshaft) that one or more cylinders are experiencing a mis-fire.

C1286 Steering Sensor Bias Malfunction
C1226 LF Excessive Wheel Speed Variation
C1278 TCS Temporarily Inhibited By PCM

I would recommend resolving the problems with the EBCM in another thread. Best to clean up the engine first.

U1016 Loss of Communications with PCM <------ DELETE
U1096 Loss of Communications with IPC <------ DELETE
U1064 Loss of Communications with BCM <------ DELETE

So where do you want to start ... the mis-fire or the throttle position sensor ?????

What did you change on the engine in the last two days when you said "Car runs like a stripped *** ape though" ??????????

 

I didnt change anything. It runs great and extremely strong till it hits the reduced engine power and everything lights up. I did do a lot of modifications to the car so this is going to get lengthy but bare with me. I rebuilt the ls1 motor with all new bearings and decided to add:LS6 intake, 5.3L pp heads with comp valvetrain, Shorty B&B headers, CIA, Brand New LS6 tb.(electronics included) I tested with both and get same issues. I have tried several different maf sensors as well. I did upgrade to the 28# injectors but cleaned them all before installing them and had my tune done for the upgrade. I did install a 2800 stall, built tranny, and 3.42 rear end. All 4 brakes where rebuilt as well. This was a winter project. Car is now all back together and trouble shooting the kinks. I cleaned all grounds. Im running NGK tr6ix due to the heads. I was going to run the tr55's but read the tr6's may be better for my application? The plugs are all connected properly and have cool socks and not grounding or being burnt by the headers. I hope i dont sound too ADHD, its just hard to try and remember everything done so im writting it as it comes to me. I know the tp sensor is good because it is brand new and the stock one did the same thing. Where do i want to start? Where ever you want me to start! I have been knocking one small thing out at a time!

Thanks for such great explination and quick replys.

I gotta give blackz06 credit. I have read a lot of his previous posts and am learning a lot.

 

Heck, let's start with the P1515

You say in your post that .....

"I know the tp sensor is good because it is brand new and the stock one did the same thing"

I want to verify .... did you replace the sensor, or is it a whole new throttle body with a new sensor in it ??

If all you replaced is the sensor, have you looked at the throttle plate to watch it in operation ???

Basically we're looking at 3 possible problems here ...

1) a mechanical problem, such as the plate "jamming" before it can get to WOT, maybe due to debris.

2) a problem with the sensor (actually there are two, but we'll cover that later).

3) a wiring problem between the sensor and the TAC.

OK, so let me know if it is a new TB and/or a new TB sensor, and then I can give you some wiring diagnostics to check.

 

It is a whole new throttle body with motor and sensor attached. I didnt replace just sensor. I got a better throttle body and all electronics where included. NEW Still in gm box. I double checked all the connections as well. Hope this helps.

Thanks!

 

I had the same thing happen to me.For some reason after changing to a fast intake my car went into lost power mode every time I would take off hard.One time I forgot to latch the hood all the way down and car ran perfect,but as soon as I latch it all the way down car would have power lost.I think I was getting a 1516 code I changed tp sensor,didn't help.Long story short I added extra ground wire to my car, problem was solved.

 

Extra ground? Where did you add it? would you have pictures?

I have extra grounds as is. I added a few when i put my motor back in.

Jeff

 

I guess this could be a possiblity now that I think about it. I did modify the tb by adding a bump stop so it stopped at exactly 90 degrees dead at wot. Otherwise it was able to open to far and shut the intake back off. I Dont think this could be the issue since it did it with both tb's though. I just notice it at wot all the time now. Whats your opinions on the tr6 plugs? Should i got with something else? Could that be the cause of the missfire?

 

The PCM expects the throttle plate to be at a certain position at WOT .... you have stopped it from getting to that position ... ya think it might throw a code ??????

TR6 plugs are a "colder" plug than stock. Usually recommended when you are generating a lot of heat, such as in Nitrous or Supercharged applications. Not recommended for "stock" engines.

For a "stock" engine most people use either the NGK TR55 or the AC Delco Iridium (41-985) plug. The NGK is usually gapped at 0.050 and the Delco comes correctly pre-gapped at 0.040 ......

It is quite possible your mis-fire is due to the plugs ... depends on what gap you have them at ... also your plug wires ... did you replace those .... most wires can get internally damaged in removing them. I recommend you consider new wires also if you don't already have new ones on .... I like the GM Performance Parts wires ... the kit is GM part number 12495519 and the kit has all eight wires in it.

 

I will try different plugs and pull the tb off tonight and get rid of the small bump stop. The wires are new msd's though. I didnt gap the ngk's because they were iridium. Was told not to. Very possible the plug is to cold and not properly gapped! Good call! Ill try these things and get back to you.

Thanks!

Jeff

 

Update...I changed the plugs and removed the bump stop in tb. All codes are now gone except i keep getting the C1286 and p0300. Can my cam be causing the car to think it is missfiring? it idles rough but not real bad. its a hot cam. When i drive its super smooth though. There is no missing or roughness to any degree if i have any amount of throttle being applied.

 

Excessive vibration in the engine could cause a P0300 to set ..... look at the "CHECK ENGINE" light, it will "flicker" or flash when a P0300 is detected .... see if it is doing it at idle. If it is, I guess it could be the cam.

The C1286 is a problem with your Steering Wheel Position Sensor (SWPS). You should test the output of the sensor at the light blue and light green wires ... each one should vary between 0 and 5 volts as you slowly turn the wheel. The voltage should remain steady with the wheel unmoving.

It will probably fail this test, which means the SWPS needs replacing.

 

Thank you! I will be getting the car tuned now and hope that cleans up the idle enough to stop that nasty p0300 code. I will be replacing the swps as well. On the road to a happy healthy vette!

Thanks for all your help! It was greatly appreciated!