Throttle position sensor

Good morning.

We need the code as there are many codes for this system. There is a also a pedal position sensor in the system as well that could be an issue.

You can have the code read at a parts store. It is a free service. Once we know the code we can narrow down the area of failure for you.

Roy

ESCRIPTION
The Throttle Position (TP) sensor is a potentiometer connected to the throttle shaft on the throttle body.

OPERATION
By monitoring the voltage on the signal line, the PCM calculates throttle position. As the throttle valve angle is changed (accelerator pedal moved), the TP sensor signal also changes. At a closed throttle position, the output of the TP sensor is low. As the throttle valve opens the TP sensor voltage increases so that at Wide Open Throttle (WOT), the TP sensor voltage should be above 4 volts. The PCM calculates fuel delivery based on throttle valve angle (driver demand).

DIAGNOSTIC INFORMATION
A broken or loose TP sensor may cause intermittent bursts of fuel from an injector and unstable idle because the PCM thinks the throttle is moving. A hard failure in the TP sensor 5 volts reference or signal circuits should set either a DTC P0122 or DTC P0123. A hard failure with the TP sensor ground circuit may set DTCs P0123 and P0117. Once a DTC is set, the PCM will use an artificial default value based on engine RPM and mass air flow for throttle position and some vehicle performance will return. A high idle may result when either DTC P0122 or DTC P0123 is set.

The PCM can detect intermittent TP sensor faults. DTC P1121 or DTC P1122 will set if an intermittent high or low circuit failure is being detected. The PCM can also detect a shifted TP sensor. The PCM monitors throttle position and compares the actual TP sensor reading to a predicted TP value calculated from engine speed. If the PCM detects an out of range condition, DTC P0121 will be set.

Yes, it is the pedal assembly. It contains the pedal sensor as well as the module for the fly by wire system.

Roy

121

CIRCUIT DESCRIPTION

The Throttle Position (TP) sensor circuit provides a voltage signal that changes relative to throttle blade angle. The signal voltage will vary from less than 1 volt at closed throttle to about 4 volts at Wide Open Throttle (WOT). The TP signal is one of the most important inputs used by the PCM for fuel control and most of the PCM-controlled outputs. The PCM monitors throttle position and compares actual throttle position from the TP sensor to a predicted TP value calculated from engine speed. If the PCM detects an out of range condition, DTC P0121 will be set.

CONDITIONS FOR SETTING THE DTC

No TP or MAP sensor DTCs set.

Idle air control is between 0 and 130 counts.

The engine is running.

MAP reading is less than 50 kPa (TP sensor high test) or greater than 60 kPa (TP sensor low test).

Throttle angle is steady.

Predicted throttle angle is not close to actual throttle angle.

The above conditions are present for at least 10 seconds.

ACTION TAKEN WHEN THE DTC SETS

The PCM will illuminate the MIL during the first trip in which the diagnostic test has been run and failed.

The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.

CONDITIONS FOR CLEARING THE MIL/DTC

The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.

The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

The DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

DIAGNOSTIC AIDS

The PCM will not complete the DTC P0121 diagnostic test until both the stuck high and the stuck low portions of the diagnostic have been completed. When verifying a repair or otherwise attempting to monitor the DTC P0121 diagnostic, refer to Conditions for Seting the DTC for the MAP signal levels required to complete both parts of the diagnostic.

Check for the following conditions:

Vacuum hoses disconnected or vacuum leaks.

Visually and physically check the for the following conditions:

- Disconnected vacuum hoses. Refer to Emission Hose Routing Diagram.

- Damaged vacuum hoses.

- Incorrect vacuum hoses routing. Refer to Emission Hose Routing Diagram.

- Damaged MAP sensor seal. Refer to MAP Sensor Replacement.

- Damaged fuel injector O-rings. Refer to Fuel Injector Replacement.

- Damaged gasket at the throttle body, intake manifold, PCV valve cover, EGR pipes, or EGR valve mounting surface.

Incorrectly installed or malfunctioning PCV valve.

Refer to Crankcase Ventilation System Inspection.

Damaged or sticking throttle plate or IAC valve.

A throttle plate or IAC valve that allows too much airflow while the throttle should be closed may cause a high idle and DTC P0121 to be set. Refer to Idle Air Control System Diagnosis.

Incorrect 3X reference signal.

An incorrect 3X reference signal can cause the MAP signal to stop updating. This condition can cause the predicted TP sensor value to be calculated incorrectly and DTC P0121 to be set. A problem with the 3X reference signal should cause DTC P1374 to be set. If DTC P1374 is set with DTC P0121, diagnose DTC P1374 first.

Skewed MAP signal or malfunctioning MAP sensor.

An incorrect MAP signal may cause the PCM to incorrectly calculate the predicted TP sensor value. Check for an unusually low MAP reading during high engine load situations or a high MAP reading at idle. Either condition can cause DTC P0121 to be set.

Stuck open EGR valve.

An EGR valve that is stuck partially open may cause the TP sensor low test to fail and DTC P0121 to be set. A sticking EGR valve should cause DTC P1406 to be set. If DTC P1406 is set with DTC P0121, diagnose DTC P1406 first.

Poor connection at PCM.

Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

Damaged harness.

Inspect the wiring harness for damage. If the harness appears to be OK, observe the TP sensor display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate the location of the malfunction.

If DTC P0121 cannot be duplicated, the information included in the Fail Records data can be useful in determining vehicle mileage since the DTC was last set. If it is determined that the DTC occurs intermittently, performing the DTC P1122 and DTC P1121 Diagnostic Charts may isolate the cause of the malfunction. See: A L L Diagnostic Trouble Codes ( DTC ) > P Code Charts > P1122 See: A L L Diagnostic Trouble Codes ( DTC ) > P Code Charts > P1121

TEST DESCRIPTION

Number(s) below refer to the Step number(s) on the Diagnostic Table:

2. An incorrect MAP signal may cause the PCM to incorrectly calculate the predicted TP sensor value during high engine load situations. Check for an unusually low MAP reading. This condition can cause DTC P0121 to be set.

12. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed. Refer to PCM Replacement and Programming Procedures in Powertrain Control Module (PCM) and Sensors.

Low battery voltage will cause a boat load of issues.

The simple answer, yes.

Roy

Good start. A fresh battery is always good for the upcoming weather and season.

Roy

You may have not installed the TPS correctly. It may not have been in contact with the arm.

Roy

Good. Leave it that way and just drive it. Sometimes it is tough to get them to seat

Roy