DTC P0121, P0122, P0123, P0221, P0222, or P0223 w/Throttle Actuator Control

Diagnostic Instructions

DTC Descriptors

DTC P0121: Throttle Position (TP) Sensor 1 Performance

DTC P0122: Throttle Position (TP) Sensor 1 Circuit Low Voltage

DTC P0123: Throttle Position (TP) Sensor 1 Circuit High Voltage

DTC P0221: Throttle Position (TP) Sensor 2 Performance

DTC P0222: Throttle Position (TP) Sensor 2 Circuit Low Voltage

DTC P0223: Throttle Position (TP) Sensor 2 Circuit High Voltage

Diagnostic Fault Information

Circuit	Short to Ground	High Resistance	Open	Short to Voltage	Signal Performance
5-Volt Reference	P0698	--	P0122, P0222	P0699	--
Throttle Position Sensor 1 Signal	P0122	P0121	P0123	P0123	P0121
Throttle Position Sensor 2 Signal	P0222	P0221	P0222	P0223	P0221
Low Reference	--	--	P0123, P0223	--	--

Typical Scan Tool Data

TP Sensor 1

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: The engine is operating at idle. Parameter Normal Range: TP Sensor 1 11-14%, 0.6-0.8 Volts
5-Volt Reference	0%, 0 Volts	0%, 0 Volts	100%, 5 Volts
TP Sensor 1 Signal	0%, 0 Volts	0%, 0 Volts	100%, 5 Volts
Low Reference	--	100%, 5 Volts	--

TP Sensor 2

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: The engine is operating at idle. Parameter Normal Range: TP Sensor 2 4.1-4.3 Volts
5-Volt Reference	0 Volts	0 Volts	5 Volts
TP Sensor 2 Signal	0 Volts	5 Volts	5 Volts
Low Reference	--	5 Volts	--

Circuit/System Description

The throttle body assembly contains 2 throttle position (TP) sensors. The TP sensors are mounted to the throttle body assembly and are not serviceable. The TP sensors provide a signal voltage that changes relative to throttle blade angle. The engine control module (ECM) supplies the TP sensors with a common 5-volt reference circuit, a common low reference circuit, and 2 independent signal circuits.

The TP sensors have opposite functionality . TP sensor 1 signal voltage increases from less than 1 volt at idle to greater than 4 volts at wide open throttle (WOT). TP sensor 2 signal voltage decreases from greater than 4 volts at idle to less than 1 volt at WOT.

Conditions for Running the DTC

P0121 or P0221

P0122, P0123, P0222, or P0223

Conditions for Setting the DTC

P0121 or P0221

The ECM detects the difference between TP sensor 1 and TP sensor 2 is greater than 6 percent for greater than 1 second.

P0122

The ECM detects that the TP sensor 1 voltage is less than 0.4 volt for greater than 2 seconds.

P0123

The ECM detects that the TP sensor 1 voltage is greater than 4.6 volts for greater than 2 seconds.

P0222

The ECM detects that the TP sensor 2 voltage is less than 0.1 volt for greater than 2 seconds.

P0223

The ECM detects that the TP sensor 2 voltage is greater than 4.9 volts for greater than 2 seconds.

Action Taken When the DTC Sets

DTCs P0121 and P0221 are Type B DTCs.

DTCs P0122, P0123, P0222, and P0223 are Type A DTCs.

Conditions for Clearing the DTC

DTCs P0121 and P0221 are type B DTCs.

DTCs P0122, P0123, P0222, and P0223 are Type A DTCs.

Diagnostic Aids

If a shared 5-volt reference circuit is shorted to ground or shorted to a voltage, other 5-volt reference circuits may be affected.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Description and Operation Reference

Throttle Actuator Control (TAC) System Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Circuit/System Verification

1. Ignition ON, observe the scan tool DTC information parameter. Verify DTCs P0698 or P0699 are not set.

⇒	If DTC P0698 or P0699 is set, refer to DTC P0642, P0643, P0698, or P0699 .

2. Observe both scan tool TP sensor voltage parameters. Verify TP sensor 1 is 0.6-0.8 volts and TP sensor 2 is 4.1-4.3 volts.
3. Engine idling, rapidly depress the accelerator pedal from the rest position to the WOT position and release pedal. Repeat the procedure several times. DTCs P0121, P0122, P0123, P0221, P0222, or P0223 should not set.
4. Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the throttle body assembly.
2. Ignition OFF for at least 20 seconds, test for less than 5 ohms of resistance between the low reference circuit and ground.

⇒	If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit and ground.

⇒	If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

⇒	If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.

4. Verify the scan tool TP sensor 2 voltage parameter is less than 0.1 volts.

⇒	If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

5. Install a 3A fused jumper wire between the TP sensor 2 signal circuit and the 5-volt reference circuit. Verify the scan tool TP sensor voltage parameter is greater than 4.8 volts.

⇒	If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

6. Verify the scan tool TP sensor 1 voltage parameter is greater than 4.8 volts.

⇒	If less than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.

7. Ignition ON, test for less than 0.1 volts on the TP sensor 1 signal circuit and ground.

⇒	If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

8. If all circuits test normal, test or replace the throttle body assembly.

Component Testing

TP Sensors

1. Remove the air inlet duct from the throtle body.
2. Ignition ON, observe the scan tool TP sensor parameters while slowly moving the throttle plate by hand, from close to wide open throttle (WOT). The voltage should change gradually in the appropriate ascending or descending value, without any spikes or dropouts, according to the specified ranges indicated in the table below.

⇒	If not within the specified ranges, replace the throttle body assembly.

Throttle Plate Position	TP Sensor 1	TP Sensor 2
Closed	14-18%, 0.6-0.7 Volts	4.1-4.3 Volts
Midpoint	48-52%, 2..4-2.5 Volts	2..4-2.5 Volts
WOT	92-96%, 4.6-4.8 Volts	0.2-0.4 Volts

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.