I just had a cam installed in my car and now I'm getting the 1120 and some others 1278,1096,1016.I know that they are probably having to do with the 1120.I had the car tuned when the cam was installed,now its acting up,I also bought a new sensor for the TB cause we thought that was out.Of course I get the reduced engine power and have to clear the codes to be able to drive the car,its fine while I'm driving,and sometimes when I shut it off it will go into reduced power,I can shut it off and start it and it will be fine,other times I have to clear the codes,could this be in the tune or is it something else.My mods are Kenne Bell S/C,ported 90 TB,228-230 cam,7.500 rods,upgraded springs,headers.x-pipe.

 

Anyone have ideas? TTT

 

It helps if you post the letter that precedes the code as that indicates which system is reporting a problem. Need to know what year car you have. Here is the diagnostic info from the 2001 Service Manual. If your car is a different year post it and I will check to see if the diagnostic is different.

DTC P1120
Circuit Description
The throttle position (TP) sensor is mounted on the throttle body assembly. The sensor is actually 2 individual TP sensors within 1 housing. Two separate signal circuits, low reference circuits and 5-volt reference circuits are used in order to connect the TP sensor assembly to the throttle actuator control (TAC) module. The 2 sensors have opposite functionality. The TP sensor 1 signal voltage is pulled up to the reference voltage as the throttle opens, from below 1 volt at closed throttle to above 3.5 volts at wide open throttle (WOT). The TP sensor 2 signal voltage is pulled down to low reference from around 3.8 volts at closed throttle to below 1 volt at WOT. TP sensor 1 and APP sensor 1 share a 5-volt reference circuit that is connected within the TAC module. TP sensor 2 and APP sensor 2 share a 5-volt reference circuit that is connected within the TAC module. If an out of range condition is detected with the TP sensor 1, this DTC will set and the Reduced Engine Power message will be displayed.

Conditions for Running the DTC
DTCs P1517, or P1518 are not set.
The ignition switch is in the crank or in the run position.
The ignition voltage greater than 5.23 volts.
Conditions for Setting the DTC
TP sensor 1 signal voltage is less than 0.13 volts or greater than 4.87 volts.
All of the above conditions present for less than 1 second.
Action Taken When the DTC Sets
The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
The control module commands the TAC system to operate in the Reduced Engine Power mode.
A message center or an indicator displays Reduced Engine Power.
Under certain conditions the control module commands the engine OFF.
Conditions for Clearing the MIL/DTC
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
Diagnostic Aids
Inspect the TAC module connectors for signs of water intrusion. When water intrusion occurs, multiple DTCs could be set with no DTC circuit or component conditions found during diagnostic testing.
When the TAC module detects a condition within the TAC system, more than one TAC system related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting the components during testing may set additional DTCs. Keep this in mind when reviewing the stored information, Capture info.
If this DTC is determined to be intermittent, refer to Intermittent Conditions .
Test Description
The number below refers to the step number on the diagnostic table.

Step 33 When the TAC module detects a condition within the TAC System, more than one TAC System related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting the components during testing may set additional DTCs. Keep this in mind when reviewing the stored information, Capture info.

DTC P1120 - Throttle Position (TP) Sensor 1 Circuit Step
Action
Values
Yes
No

Schematic References: Engine Controls Schematics

Step 1
Did you perform the Diagnostic System Check-Engine Controls?
--
Go to Step 2
Go to Diagnostic System Check - Engine Controls

Step 2
Is DTC P1515, P1516, or P1518 also set?
--
Go to Diagnostic Trouble Code (DTC) List
Go to Step 3

Step 3
Turn OFF the ignition.
Remove the air inlet duct from the throttle body assembly.
Disconnect the throttle actuator motor harness connector.
Turn ON the ignition, with the engine OFF.
Manually close the throttle blade completely while observing the TP sensor 1 voltage on the scan tool.
Does the scan tool indicate TP sensor 1 voltage within the specified values?
0.13-0.67 V
Go to Step 4
Go to Step 8

Step 4
Manually open the throttle blade to wide open throttle (WOT) while observing the TP sensor 1 voltage parameter on the scan tool.

Does the scan tool indicate that the TP sensor 1 voltage is within the specified values?
4.09-4.87 V
Go to Step 5
Go to Step 8

Step 5
Disconnect the TP sensor harness connector.
Disconnect the TAC module harness connector containing the TP sensor circuits.
With a DMM, test the TP sensor low reference circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 32
Go to Step 6

Step 6
Turn OFF the ignition for 15 seconds.
Reconnect the TAC module harness connector.
Reconnect the throttle actuator motor harness connector.
Reinstall the air inlet duct.
Turn ON the ignition, with the engine OFF.
Select the DTC Info. option on the scan tool.
Lightly touch and move the related engine wiring harnesses and connectors for the TP sensor while observing the DTC Info. The DTC will set if an intermittent condition is present. Refer to Connector Repairs and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 32
Go to Step 7

Step 7
Continue to observe DTC Info.
Slowly depress the accelerator pedal to WOT, and then slowly return the pedal to the released position 3 times.
Does the scan tool indicate this DTC failed this ignition?
--
Go to Step 27
Go to Diagnostic Aids

Step 8
Disconnect the TP sensor harness connector.
Measure voltage at the TP sensor 1 signal circuit with a DMM connected to ground.
Does the DMM indicate voltage within the specified values?
3.94-6.06 V
Go to Step 13
Go to Step 9

Step 9
Turn OFF the ignition.
Disconnect the TAC module harness connector containing the TP sensor circuits.
Turn ON the ignition with the engine OFF.
With a DMM, test the TP sensor 1 signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 32
Go to Step 10

Step 10
With a DMM, test the TP sensor 1 signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 32
Go to Step 11

Step 11
With a DMM, test the TP sensor 1 signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 32
Go to Step 12

Step 12
Disconnect the other TAC module harness connector.
With a DMM, test for a short between the TP sensor 1 signal circuit and all other TAC module circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 32
Go to Step 28

Step 13
With a DMM, test the TP sensor 1, 5-volt reference circuit for voltage.

Does the DMM indicate voltage within the specified values?
3.94-6.06 V
Go to Step 23
Go to Step 14

Step 14
Does the DMM indicate voltage greater than the specified value?
6.06 V
Go to Step 15
Go to Step 17

Step 15
Turn OFF the ignition.
Disconnect the TAC module harness connector containing the TP sensor circuits.
Turn ON the ignition with the engine OFF.
With a DMM, test the TP sensor 1, 5-volt reference circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 32
Go to Step 16

Step 16
Turn OFF the ignition.
Disconnect the APP sensor harness connector.
Disconnect the other TAC module harness connector.
Turn ON the ignition, with the Engine OFF.
With a DMM, test the APP sensor 1, 5-volt reference circuit for a short to voltage . Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 32
Go to Step 21

Step 17
Disconnect the APP sensor.

Does the DMM indicate voltage less than the specified value?
3.94 V
Go to Step 18
Go to Step 30

Step 18
Disconnect the TAC module harness connector containing the TP sensor circuits.
With a DMM, test the TP sensor 1, 5-volt reference circuit for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 32
Go to Step 19

Step 19
With a DMM, test the TP sensor 1, 5-volt reference circuit for a short to ground.

Did you find and correct the condition?
--
Go to Step 32
Go to Step 20

Step 20
With a DMM, test the APP sensor 1, 5-volt reference circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 32
Go to Step 21

Step 21
With a DMM, test for a short between the TP sensor 1 5-volt reference circuit and all other TAC module circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 32
Go to Step 22

Step 22
With a DMM, test for a short between the APP sensor 1 5-volt reference circuit and all other TAC module circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 32
Go to Step 28

Step 23
Disconnect the TAC module connector containing the TP sensor circuits.
With a DMM, test the TP sensor 1 signal circuit for a short to any other TP sensor circuit. If a short is found refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 32
Go to Step 24

Step 24
Reconnect the TAC module harness connector containing the TP sensor circuits.
Connect a fused jumper between the TP sensor 1 low reference circuit and the TP sensor 1 signal circuit.
With a scan tool, observe the TP sensor 1 voltage parameter.
Does the scan tool indicate voltage near the specified value?
0 V
Go to Step 26
Go to Step 25

Step 25
Turn OFF the ignition.
Disconnect the TAC Module harness connector containing the TP sensor circuits.
With a DMM, test the TP sensor 1 low reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 32
Go to Step 28

Step 26
Inspect for poor connections at the TP sensor harness connector. Refer to Testing for Intermittent and Poor Connections and Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 32
Go to Step 29

Step 27
Inspect for poor connections at the APP module harness connector. Refer to Testing for Intermittent and Poor Connections and Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 32
Go to Step 30

Step 28
Inspect for a poor connection at the TAC Module harness connector. Refer to Testing for Intermittent and Poor Connections and Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 32
Go to Step 31

Step 29

Important
The throttle position sensor is not a serviceable part and should only be replaced with the throttle body assembly.


Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement .

Did you complete the replacement?
--
Go to Step 32
--

Step 30
Replace the APP sensor. Refer to Accelerator Pedal Position (APP) Sensor Replacement .

Did you complete the replacement?
--
Go to Step 32
--

Step 31
Replace the TAC module. Refer to Throttle Actuator Control (TAC) Module Replacement .

Did you complete the replacement?
--
Go to Step 32
--

Step 32
Use the scan tool in order to clear the DTCs.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC run and pass?
--
Go to Step 33
Go to Step 2

Step 33
With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?
--
Go to Diagnostic Trouble Code (DTC) List
System OK

If you do not have access to a Tech 2 do the things that can be done without using a Tech 2 and see if you can find the problem.

Bill

 

Bill,

Thanks for all the info,while I was looking on the forum I kept noticing that others were having there Batteries checked and on some of the problems that was what it was,so I went and had mine checked and sure enough my Battery was bad,put a new one in and drove around for awhile and it all seems to be good,I need to go back to the tuner that installed the cam and have him make some other adjustments with the idle,but for now all the other issues seem to be ok.