DTC P1120 Throttle Position (TP) Sensor 1 Circuit. Cadillac Catera 1999

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 1999 🢒 Catera 🢒 DTC 🢒 DTC P1120 Throttle Position (TP) Sensor 1 Circuit

Handling ESD Sensitive Parts Notice
Engine Controls Components
Cell 20: Throttle Position (TP) Sensor
OBD II Symbol Description Notice

Circuit Description

The TP sensor 1 is part of the electronic throttle control system (ETC). The TP sensor 1 is the main input to the ECM for actual throttle positioning. The ECM supplies the TP sensor 1 with a 5 volt reference and a ground circuit. The TP sensor 1 sends a voltage to the ECM on the signal circuit. The ECM then calculates the throttle angle opening based on this voltage.

Conditions for Running the DTC

The battery voltage is more than 7.0 volts.

Conditions for Setting the DTC

•	The throttle position (TP) sensor 1 voltage is less than 0.195 volt, or more than 4.6 volt.

•	The difference between TP sensor 1 and TP sensor 2 is more than 13 percent.

•	One of the above conditions is met for 140 ms (0.140 seconds).

Action Taken When the DTC Sets

•	The engine control module (ECM) illuminates the malfunction indicator lamp (MIL) on the first drive trip that the diagnostic runs and fails.

•	The ECM attempts to record the operating conditions in the Freeze Frame.

•	The vehicle will default to the limp home mode.

Conditions for Clearing the MIL/DTC

•	The ECM turns off the malfunction indicator lamp (MIL) after 3 consecutive drive trips that the diagnostic runs and passes.

•	A History DTC clears after forty consecutive warm-up cycles in which no failures are reported by this diagnostic or any other emission related diagnostic.

•	The ECM battery voltage is interrupted.

•	The scan tool clears the MIL/DTC.

Diagnostic Aids

With the ignition ON and the engine OFF, view the TP sensor 1 and the TP sensor 2 with a scan tool. Slowly depress the accelerator pedal, the voltage on TP sensor 1 should increase steadily from 0.2 volt to about 4.6 volt. TP sensor 2 should move opposite from above 4.0 to about 0.2 volt. If one sensor value changes and the other does not, inspect the sensor circuits for high resistance or shorts. If the circuits are OK replace the TP sensor.

Notice: Using the J 35616-A Connector Test Adapter Kit will prevent damage to the harness connector terminals.

Use the J 35616 connector test adapter kit for any test that requires probing the ECM harness connector or a component harness connector.

Check for the following conditions:

•	Poor connections at the ECM or at the component--Inspect the harness connectors for a poor terminal to wire connection. Refer to Engine Control Module Diagnosis , Checking Terminal Contact, for the proper procedure.

•	Damaged harness--Inspect the wiring harness for damage. If the harness appears to be OK, observe the scan tool while moving the related connectors and the wiring harnesses. A change in the display may help locate the fault.

Refer to Symptoms for the Intermittents.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

This step tests for the proper operation of the circuit. The ECM supplies a pull up voltage of about 5 volts on the signal circuit.

This step tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to B+.

This step tests for a high resistance or an open in the ground circuit.

Step	Action	Values	Yes	No
1	Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?	--	Go to Step 2	Go to Powertrain On Board Diagnostic (OBD) System Check
2	Install a scan tool. Turn ON the ignition leaving the engine OFF. With a scan tool, observe the TP sensor 1 parameter in the engine control module data list. Does the scan tool indicate that the TP sensor 1 parameter is within the specified range?	4.6 V to 0.2 V	Go to Diagnostic Aids	Go to Step 3
3	Turn OFF the ignition. Disconnect the TP sensor 1. Turn ON the ignition leaving the engine OFF. With a scan tool, observe the TP sensor 1 parameter. Does the scan tool indicate that the TP sensor 1 parameter is more than the specified value?	4.6 V	Go to Step 4	Go to Step 11
4	Turn OFF the ignition. Connect a 3 amp fused jumper wire between the signal circuit of the TP sensor 1 and a known good ground. Turn ON the ignition leaving the engine OFF. Using a scan tool, observe the TP sensor 1 parameter. Does the scan tool indicate that the TP sensor 1 parameter is less than the specified value?	0.2 V	Go to Step 5	Go to Step 10
5	Turn OFF the ignition. Connect a 3 amp fused jumper wire between the signal circuit of the TP sensor 1 and REF Ground circuit. Turn ON the ignition leaving the engine OFF. Using a scan tool, observe the TP sensor 1 parameter. Does the scan tool indicate that the TP sensor 1 parameter is less than the specified value?	0.2 V	Go to Step 6	Go to Step 12
6	Disconnect the fused jumper wire. Measure the voltage between the 5 volt reference circuit of the TP sensor 1 and the ground circuit of the TP sensor 1. Does the voltage measure within the specified value?	4.8-5.2 V	Go to Step 13	Go to Step 7
7	Is the voltage less than the specified value?	4.8 V	Go to Step 9	Go to Step 8
8	Test the 5 volt reference circuit of the TP sensor 1 for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 17	Go to Step 14
9	Test the 5 volt reference circuit of the TP sensor 1 for a short to ground, a high resistance, or an open. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 17	Go to Step 14
10	Test the signal circuit of the TP sensor 1 for a short to voltage, a high resistance, or an open. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 17	Go to Step 14
11	Test the signal circuit of the TP sensor 1 for a short to ground or to the reference ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 17	Go to Step 14
12	Test the ground circuit of the TP sensor 1 for a high resistance or an open. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 17	Go to Step 14
13	Inspect for poor connections at the harness connector of the TP sensor 1. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 17	Go to Step 15
14	Inspect for poor connections at the harness connector of the engine control module. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 17	Go to Step 16
15	Replace the throttle body assembly. Refer to Throttle Body/Throttle Position Sensor Replacement . Did you complete the replacement?	--	Go to Step 17	--
16	Important: Perform the Idle Learn Procedure when replacing the ECM or the throttle body. Important: This vehicle is equipped with a theft deterrent system that interfaces with the engine control module (ECM). Program the new ECM with the frequency code of the theft deterrent module that is currently on the vehicle. Replace the ECM. Refer to Engine Control Module Replacement/Programming . Is the action complete?	--	Go to Step 17	--
17	Use a scan tool in order to clear the DTCs. Start the engine. Allow the engine to idle until the engine reaches the normal operating temperature. Select DTC and the Specific DTC function. Enter the DTC number that was set. Operate the engine within the Conditions for Running this DTC until the scan tool indicates the diagnostic Ran. Does the scan tool indicate the diagnostic Passed?	--	Go to Step 18	Go to Step 2
18	Does the scan tool display any additional, undiagnosed DTCs?	--	Go to the applicable DTC table	System OK