DTC P0122 Throttle Position (TP) Sensor Circuit Low Voltage. Chevrolet Malibu 1997

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 1997 🢒 Malibu 🢒 DTC 🢒 DTC P0122 Throttle Position (TP) Sensor Circuit Low Voltage

Engine Controls Components
Engine Data Sensors
OBD II Symbol Description Notice
Engine Controls Connector End Views
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The PCM supplies a 5V reference signal and a ground to the sensor. The TP sensor sends a voltage signal back to the PCM relative to the throttle plate opening. The voltage will vary from approximately 0.45Vat closed throttle, to over 4.5V at wide open throttle.

Conditions for Setting the DTC

•	The engine is running.

•	The TP sensor is less than 0.16V for 5 seconds.

Action Taken When the DTC Sets

•	The Malfunction Indicator Lamp (MIL) will illuminate.

•	The PCM will record the operating conditions at the time that the diagnostic fails. This information will store in the Freeze Frame and Failure Records buffers.

•	A history DTC stores.

•	The coolant fan turns ON.

•	The TP angle will default to 0 percent when the vehicle speed is less than 3 km/h (2 mph) and 10 percent when the vehicle speed is greater than 3 km/h (2 mph) (The scan tool will display the defaulted value).

Conditions for Clearing the MIL/DTC

•	The MIL will turn OFF after three consecutive ignition cycles in which the diagnostic runs without a fault.

•	A history DTC will clear after 40 consecutive warm-up cycles without a fault.

•	The MIL/DTCs can be cleared by using the scan tool.

Diagnostic Aids

If a DTC P0122 cannot be duplicated, the information included in the Freeze Frame data can be useful. Use the scan tool DTC information data in order to determine the status of the DTC. If the DTC occurs intermittently, use the DTC P0121 Diagnostic table in order to help isolate the problem.

Test Description

The number(s) below refer(s) to the step number(s) on the Diagnostic Table.

The Powertrain OBD System Check prompts you to complete some of the basic checks and to store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data captured when the fault occurred. The scan tool stores this data for later reference.

The TP sensor has an auto zeroing feature. If the voltage reading is between 0.20 V and 0.90 V, the PCM will automatically assume this as a closed throttle position (0 percent).

This simulates a DTC P0123. If the PCM recognizes the high voltage signal, this indicates that the PCM and the wiring are OK.

This simulates a high voltage signal which will identify an open in the signal circuit.

If any additional DTCs are set, check the 5.0 V reference circuits for a short to ground.

If the test light illuminates while probing the TP signal circuit terminal, then the TP signal circuit is shorted to ground.

Reprogram the replacement PCM and perform the crankshaft position system variation learning procedure. Refer to the latest Techline information for PCM programming and the Powertrain Control Module (PCM) for the crankshaft position system variation learning procedure.

DTC P0122-Throttle Position (TP) Sensor Circuit Low Voltage

Step	Action	Value(s)	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	Turn ON the ignition leaving the engine OFF. Install a scan tool. Is the TP sensor voltage below the specified value?	0.2 V	Go to Step 4	Go to Step 3
3	Turn ON the ignition leaving the engine OFF. Review the Freeze Frame data and record the parameters. Operate the vehicle within the Freeze Frame conditions and Conditions For Setting the DTC as specified. Is the TP sensor voltage below the specified value?	0.2 V	Go to Step 4	Go to Step 12
4	Disconnect the TP sensor electrical connector. Connect a jumper wire between the 5.0 V reference circuit terminal and the TP sensor signal circuit terminal at the TP sensor electrical connector. Is the TP sensor voltage greater than the specified value?	4.0 V	Go to Step 10	Go to Step 5
5	Connect a test light between B+ and the TP sensor signal circuit at the TP sensor electrical connector. Is the TP sensor voltage greater than the specified value?	4.0 V	Go to Step 6	Go to Step 8
6	Check the 5.0 V reference circuit for an open or a short to ground and repair the circuit as necessary. Was a repair necessary?	--	Go to Step 12	Go to Step 7
7	Check the 5.0 V reference circuit for a poor connection at the PCM. Replace the terminal(s) as necessary. Was a repair necessary?	--	Go to Step 12	Go to Step 11
8	Check the TP sensor signal circuit for an open or a short to ground and repair the circuit as necessary. Was a repair necessary?	--	Go to Step 12	Go to Step 9
9	Check the TP sensor signal circuit for a poor connection at the PCM and repair the circuit as necessary. Is the action complete?	--	Go to Step 12	Go to Step 11
10	Replace the TP sensor. Is the action complete?	--	Go to Step 12	--
11	Replace the PCM. Is the action complete?	--	Go to Step 12	--
12	Clear the DTCs with the scan tool. Start the engine. Idle the engine at the normal operating temperature. Operate the vehicle within the conditions for setting this DTC as specified in the supporting text. Does the scan indicate that this diagnostic ran and passed?	--	Go to Step 13	Go to Step 2
13	Check to see if any additional DTCs are set. Does the scan tool display any DTCs that you have not diagnosed?	--	Go to applicable DTC table	System OK