Belovic

I am broke down........
Drove the Z06 to a car show about 2hrs away. Made it home and as i made the final turn home i lost power

Went to Reduced engine mode/trac control/stability control

Yes the famous 1120,1220,1516,1518,1278,1000 and 1064 codes

I have replaced the TPS, the throttle body and have cleaned and checked all grounds.
I did find and correct the wires that go to the crank sensor that were basically melted and I did find and correct the worn wiring harness on the top/rear driver side of the engine.

I have reached out to Bill C for advice and recommended a voltage check on the TAC fuse and the TPS. I will try to do this tonight.

As for now, the car immediatly triggers these codes even without starting.

HELP.....anybody???

73Corvette

Any codes will show up as History codes unless you clear them... then pull the codes BEFORE you kill the car... they will be your current codes...

Bill Curlee

I agree,,,, CLEAR ALL DTCs... Turn the ignition on. PRESS RESET to clear any DIC Messages (i.e. Reduced Power)

Read the DTCs in that ignition cycle WITHOUT turning the ignition key OFF

Report findings

Are any other weird things happening??? Doors don't work, weird IPC gage readings????

Let us know..

Bill

Belovic

Did as you mentioned.
Code came back was P1515

tried starting and it had throttle for a second then back to fail mode with all 1120, 1220, 1516, 1518

we did validate via a scan tool the TPS is reading the throttle position so good there.......

next check is the throttle motor?? Tac Module?? aaaaahhhhhhhhhhh

tblu92

How long was the car running fine before all these codes popped up? have you done ANY mods since it was all running fine ??
The P codes are all engine related--The others are all results of the P codes
Have you tried di connecting the battery overnite to completely unload the ECM?If not do this 1st as if your car was running fine before these new codes may all be simply glithes

Belovic

Car was running fine forever. I had an Trac Control issue and had the unit repaired but have driven it for 6 months or so with no issue.

Prior to this failure i did sit in traffic for an hr or so at 100 deg then drove for 2 hrs then rain hit and then the car crapped out.

No modifications other than a K&N cold air intake, xpipe and BB mufflers. No engine mods.

Idid find the wiring harness on top of engine driver side did have a slight wear point as it went behind the fuel rail and i did find heated wires that go to the crank sensor.
Other than the harness feeling rock hard, i beleive they are now corrected.

I have validated TPS function and power to the TAC module.

Still dead............

Belovic

yes i have also taken the battery out for overnite and days actually.
Took it to be tested and it tested good and has between 12.58 and 12.73 volts when charged. Also noted that the alternator is pumping out over 14 volts

Bill Curlee

P1515

P1515 Chevrolet

P1515 Chevrolet - Control Module Throttle Actuator Position Performance




What does this mean?



PDF Share Code

0 P1515 Chevrolet Comments | Add Comment


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Possible causes

- Poor connection at the Throttle Actuator Control (TAC) module
- Faulty TAC module
- Faulty Throttle Pedal Position (TPP) or Throttle Position (TPS) sensors
- Binding or bent throttle plate-failed throttle body

What does this mean?

When is the code detected?

The Powertrain Control Module (PCM) has detected a throttle plate out of position based on commanded and actual throttle plate position

Possible symptoms

- Engine Light ON (or Service Engine Soon Warning Light)

P1515 Chevrolet Description


The Throttle Actuator Control (TAC) system uses vehicle electronics and components to calculate and control the position of the throttle blade. This eliminates the need for a mechanical cable attachment from the accelerator pedal to the throttle body. This system also performs the cruise control functions as well.

The TAC system components include, but are not limited to the following:

- The accelerator pedal position (APP) sensors

- The throttle body

- The powertrain control module (PCM)

Each of these components interface together to ensure accurate calculations and control of the throttle position (TP).

Throttle Body Assembly

The throttle body for the throttle actuator control (TAC) system is similar to a conventional throttle body with several exceptions. One exception being the use of a motor to control the throttle position instead of a mechanical cable. Another exception is the throttle position (TP) sensor. The TP sensor is mounted in the throttle body assembly. The TP sensor is 2 individual TP sensors within the throttle body assembly. Two separate signal, low reference, and 5-volt reference circuits are used to connect the TP sensors and the powertrain control module (PCM). TP sensor 2 signal voltage increases as the throttle opens. TP sensor 1 signal voltage decreases as the throttle opens.


Those wires in the drivers side engine harness are really suspect. If it were me,, I would untape it examine each wire..

Bill

Belovic

will do

is it normal for the harness to be rigid and the wires appear to be press together yet not showing as copper to copper touching.
ir is difficult to seperate the wires

Belovic

Note:
the wires that appear to have been impacted were the wires that feed the fuel injector nearest the back of the driver side engine top

Bill Curlee

NO,,, the wires should be seperate and move in the harness. Thats why its IMPORTANT to seperate ALL the wires and inspect them ALL. Look for insulation breaks, bare copper, conductors broken inside the plastic insulator.

Its pretty easy to rewrap the harness.

I has a pinched pink 12 VDC Power wire for the coils:

tblu92

Here is another website that goes thru simple tests and simple reasons for codes---Remember the TAC is the "Throttle actuator control" so basically your T-Body----The T-Body control IS used by the traction control system to limit wheel spin by limiting throttle opening--So they are related to a common issue and codes---
Gearchatter is a great site and not so technical that you don't know what they are trying to say---
http://www.gearchatter.com/viewpost14490.php

Belovic

OK
It is fixed.........!!!!!!!!!

In Summary:
Reduced engine, stability control, traction control and check engine light came on.
Codes thrown, 1120,1220,1516,1518,1278,u1000,u1064

Efforts:
Purchased installed TPS ($59 on Amazon)
Purchased used throttle body: $75.00 Craigslist
Checked, cleaned all 13 ground points
Fixed wiring harness issue on top of engine near fuel rail
Repaired overheated crank sensor wiring harness
Tested Fuse 17 and all of its components
Tested TPS wire harness for shorts
Purchased and installed TAC Module ($219 on Ebay)

Ultimately the TAC module fixed it.
But.......Needed to fix the wiring harnesses and the grounds

Thank you to all for your help. If it was not for this community, i would have been in real trouble. By going thru all the troubleshooting I really got to know my car. What an awesome education.

Thanks
Mike

73Corvette

Nice work to all involved