DTC P1121: Throttle Position (TP) Sensor: Condition

This code indicates TP signal is inconsistent with MAF sensor signal. Possible causes for this fault are as follows:

TP sensor not seated correctly.
Faulty TP sensor.
Air leak between MAF sensor and throttle body.

Normal range of throttle angle measurement for TP sensor is 0-85 degrees. To pass quick test procedure, range of throttle rotation (in degrees) must be within 3 percent of specification.

To prevent replacement of good components, be aware, the following areas may be at fault:

Idle speed.
Binding throttle shaft or linkage.
TP sensor not seated.

Continuous Memory Code P1121

If engine will start, go to next step. If engine is a no-start, check for cracks or openings in air induction system between MAF sensor and throttle body.

Check Operation Of TP Sensor

Start engine and allow to idle. Access TP PID on scan tool. While observing TP PID, slowly move throttle through range from closed position to wide open throttle. If TP PID indicates any sudden drops to below 0.53 volt, or increases to greater than 1.27 volts, replace TP sensor and repeat QUICK TEST. See TESTS W/CODES - INTRODUCTION article. If TP PID increase and decrease is gradual and smooth, and within 0.53-1.27 volt range, go to next step.

Check Operation Of TP Sensor While Driving Vehicle

Connect scan tool to DLC. Drive vehicle while accessing TP PID and LOAD PID. If TP PID is 2.44 volts or less and LOAD PID is greater than 25 percent, go to next step. If TP PID is greater than 2.44 volts and LOAD PID is less than 25 percent, check for cracks or openings in air induction system between MAF sensor and throttle body. If air induction system is okay, replace TP sensor.

Check TP Sensor Low With Engine Under Load

Start engine and allow to idle. Access TP PID and LOAD PID on scan tool. If TP PID is 0.24 volt or more and LOAD PID is less than 60 percent, fault is intermittent and cannot be located at this time. Testing is complete. If TP PID is less than 0.24 volts and LOAD PID is 60 percent or more, clear PCM memory. Perform test drive utilizing all phases of vehicle operation. Perform QUICK TEST. See TESTS W/CODES - INTRODUCTION article. If DTC P1121 is still present, replace MAF sensor.