Spark

DTC P0122, P0123, P0222, P0223, or P2135 - FX3

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

The throttle position sensors have opposite functionality. Throttle position sensor 1 signal voltage decreases and throttle position sensor 2 signal voltage increases as the accelerator pedal increases to wide open throttle (WOT).

P0122

The ECM detects that the TP sensor 1 signal voltage is less than 0.25V.

P0123

The ECM detects that the TP sensor 1 signal voltage is greater than 4.75V.

P0222

The ECM detects that the TP sensor 2 signal voltage is less than 0.25V.

P0223

The ECM detects that the TP sensor 2 signal voltage is greater than 4.75V.

P2135

The ECM detects that the difference between TP 1 and TP 2 is greater than the predetermined values.

DTC P0122, P0123, P0222, P0223, and P2135 are Type A DTCs.

DTC P0122, P0123, P0222, P0223, and P2135 are Type A DTCs.

Schematic Reference

Engine Controls Schematics : Siemens ECM - LPG with LCP → Siemens ECM - Gas without FX3 or LCP → Delphi ECM - FX3

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the Throttle Position Sensor 1 parameter. The reading should be between 0.18-4.63V and change with accelerator pedal input.
2. Ignition ON, observe the Throttle Position Sensor 2 parameter. The reading should be between 4.7-0.13V and change with accelerator pedal input.
3. Observe the DTC Information with a scan tool. DTCs P0122, P0123, P0222, P0223, and P2135 should not set.
4. Observe both Throttle Position Sensor 1 and Throttle Position Sensor 2 percentage parameters while quickly pressing the accelerator pedal from a closed throttle to WOT. Both Throttle Position Sensor 1 and Throttle Position Sensor 2 percentage parameters should change.
5. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

Note: You must perform the circuit/system verification before proceeding with circuit/system testing.

1. Ignition OFF, disconnect the harness connector at the Q38 throttle body. Allow sufficient time for the K20 engine control module to completely power down.
2. Ignition OFF, test for less than 5Ω between the Q38 throttle body harness connector low reference circuit terminal C and ground.

⇒	If greater than 5 Ω, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 engine control module.

3. Ignition ON, test for 4.8-5.2V between the Q38 throttle body harness connector 5V reference circuit terminal E and ground.

⇒	If less than the specified range, test the 5V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.

⇒	If greater than the specified range, test the 5V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 engine control module.

4. Test for less than 1V between the Q38 throttle body harness connector throttle position sensor 1 signal circuit terminal D and ground.

⇒	If greater than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 engine control module.

5. Test for 4.8-5.2V between the Q38 throttle body harness connector throttle position sensor 2 signal circuit terminal F and ground.

⇒	If less than specified range, test the signal circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.

⇒	If greater than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 engine control module.

6. Install a 3A fused jumper wire between Q38 throttle body harness connector throttle position sensor 1 signal circuit terminal D and the 5V reference circuit terminal E. Verify the scan tool throttle position sensor 1 voltage parameter is greater than 4.8V.

⇒	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 K20 engine control module.

7. Install a 3A fused jumper wire between Q38 throttle body harness connector throttle position sensor 2 signal circuit terminal F and the low reference circuit terminal C. Verify the scan tool throttle position sensor 2 voltage parameter is less than 0.1V.

⇒	If greater than the specified range, test the signal circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.

8. Ignition OFF, disconnect the ECM harness connector at the K20 engine control module.
9. Test for less than 5Ω on all Q38 throttle body harness connector throttle position sensor circuits between the following terminals:

•	The 5V reference circuit terminal E to the corresponding ECM terminal 21.

•	The throttle position sensor 2 signal circuit terminal F to the corresponding ECM terminal 65

•	The throttle position sensor 1 signal circuit terminal D to the corresponding ECM terminal 66

⇒	If greater than 5 Ω, repair the affected circuit.

10. Test for infinite resistance between Q38 throttle body throttle position sensor 1 signal circuit terminal D and throttle position sensor 2 signal circuit terminal F.

⇒	If less than infinite resistance, repair the short circuit between Q38 throttle body throttle position sensor 1 signal circuit and throttle position sensor 2 signal circuit.

11. If all circuits test normal, replace the Q38 throttle body.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.