2002 vette,
So a week back I was driving home and did not think the water was so high from the rain in front of my drive way turned out to be 9in of water. Turned out I pulled water into my intake. The second I noticed my car was having problems I shut it down and pushed it up the street to dry ground. I Pulled the intake off and opened the TB and a small amount of water came out. I started it up right away and it smoked a bit but then ran just fine. Later that night Its Service Engine and Service TCS came on and it went into reduced power mode now it will only run up to 2k. I checked my grounds and replaced my TPS. Still nothing. The codes I am getting are. P1120HC,P1220HC,P1221H,P1551H,P1516HC, TCS P1278HC. Please Help.

 

P1120 TP Sensor 1 Circuit
P1220 TP Sensor 2 Circuit
P1221 TP Sensors 1, 2 Performance
P1551 ?
P1516 Command vs Actual Throttle Position Performance (TAC Module)
C1278 TCS Temporarily Inhibited By PCM

I'm thinking your P1551 is really P1515 which is:P1515 Command vs Actual Throttle Position Performance (PCM Module)

Water intrusion is obvious. I'd be looking at the TAC module to PCM connection as well as the throttle position plate wiring.

 

The 1551 was a mistake your correct 1515 but that doesn't show up anymore. So i got to my TAC. What should I be looking for? also what wiring where you talking about ?

 

Sorry, I wasn't very clear. The TP Sensor is at the gas pedal itself inside of the car but there is a position feedback at the intake throttle plate and all of it goes to the TAC. Now I'm saying all this based only on function as I have no schematics but either Bill Curlee or Lucky131969 will have them and can better advise you. Water hitting all of a sudden, I tend to doubt that it got inside to the pedal but its something you need to be looking at. Up on top of the intake is a stepper motor which is the true throttle or throttle plate. Its connector is exposed to the elements as such and I would be looking at its connector for proper seating and cleanliness of the contacts. As for the TAC module which is also exposed to the elements, make sure the battery is disconnected before touching it. About the only thing I can tell you to do without schematics is again, to look for the contact cleanliness.

 

went threw the rest of the grounds today and re cleaned all the problems also went threw the TAC today and cleaned its connections. The only problem wire i found was one next to the alternator that was behind it and was rubbed free of its housing fixed that. The the wires that run behind the engine next to the fuel rail were fine. I don't no where to turn to next. Any Ideas?

 

This might help.
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Throttle Actuator Control (TAC) System Description




(1) Throttle Actuator Control (TAC) Module
(2) Throttle Body Assembly
(3) Accelerator Pedal Position (APP) Sensor

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

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

The accelerator pedal position (APP) sensor
The throttle body
The throttle actuator control (TAC) module
The powertrain control module (PCM)
Each of these components interface together in order to ensure accurate calculations, and in order to control the throttle position.

Accelerator Pedal Position (APP) Sensor



The accelerator pedal position (APP) sensor is mounted on the accelerator pedal assembly. The APP is actually 3 individual accelerator pedal position sensors within 1 housing. Three separate signal, low reference, and 5-volt reference circuits are used in order to connect the APP and the TAC module. The APP sensor 1 voltage should increase at the same time that the accelerator pedal is depressed, from below 1 volt at 0 percent pedal travel to above 2 volts at 100 percent pedal travel. APP sensor 2 voltage should decrease from above 4 volts at 0 pedal travel to below 2.9 volts at 100 percent pedal travel. APP sensor 3 voltage should decrease from above 3.8 volts at 0 pedal travel to below 3.1 volts at 100 percent pedal travel.

Throttle Body Assembly



The throttle body for the TAC system is similar to a conventional throttle body with some exceptions. One exception is the use of a motor to control the throttle position (TP) instead of a mechanical cable. The other exception is the new design TP sensor. The TP sensor mounts on the side of the throttle body opposite the throttle actuator motor. The TP sensor is actually 2 individual TP sensors within 1 housing. Separate low reference and 5-volt reference circuits are used in order to connect the TP sensors and the TAC module. The TP sensor 1 signal voltage increases at the same time that the throttle opens. The voltage increases, from approximately 1 volt at 0 throttle to above 3.5 volts at 100 percent throttle. TP sensor 2 signal voltage decreases at the same time that the throttle is opened. The voltage increases from approximately 3.8 volts at 0 throttle to below 1 volt at 100 percent throttle.

Throttle Actuator Control (TAC) Module



The TAC module is the control center for the electronic throttle system. The TAC module and the PCM communicate via a dedicated redundant serial data circuit. The TAC module and the PCM monitor the commanded throttle position and compare the commanded position to the actual throttle position. This is accomplished by monitoring the APP and the TP sensor. These 2 values must be within a calibrated value of each other. The TAC module also monitors each individual circuit of the TP sensor, and of the APP to verify proper operation.


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A little lost with this at the moment.

 

Acutally, the TP (throttle position sensor) is on the throttle body itself. What you are referring to, is the APP (accelerator position sensor).

 

What's done is done, but starting the car after water ingestion, is the worst thing you could possibly do.....without pulling the plugs first.

The first thing I would do, is check underhood fuse 17.

 

How do you get to the APPS. I looked and theirs A large plastic plate in the way. Also how do I trouble shoot a problem with that sensor?

 

It's located at the pedal, and would be the LEAST likely cause....given the circumstances. .......and fuse 17?

 

17 is good just checked

 

Also side note the care is about 2in lower then stock. Whats the chances That i drown the TAC?

 

You tell me.......how much of the vehicle was submerged?

 

i was driving up to the start of my driveway where theirs a dip and i was told the top of the two large front intake vents had water in them. That was just the front back by the doors it was just at the bottom of the side skirts.

 

Have you tried to clear ALL the DTCs and see what comes back? If it were me,, I would change the Throttle Position Sensor on the Throttle Body.. Its on the PASSENGERS SIDE of the TB and secured by two fateners. Easy change and you can get the part at the Auto Parts Store.

BC

 

Already changed the TPS. Still get codes 1120,1220,1516.

 

Just went back threw the wire harness and still drawing blanks the wire harness is coming up fine. Is there a way to test if the TAC mod is bad?

 

I had the exact same situation. Lowered Z06 C5 and ran through water that caused engine to stall. I had all the same codes and all the preventives were completed. Dealership said voltage was too low. They ordered a TAC module but back order has taken nearly three months. Part due in 27 SEP 2011. Hopefully u won't need one.

 

So got a scanner from work. It seems good Snapon Modis EEMS300. I hooked it up and tried out both of my TPS sensors on. Funny thing is the new tps didnt read anything. The old one if i manually opend the TB and close it it read 0closed 100 WOT. But then when i let it go back to stock 7% TP the sensor read 12%. So i would start the car and i would give it gas the APP read and was ok the TP would not respond I took pictures. Please give feed back. http://i2.photobucket.com/albums/y12...-21-45_777.jpg