P0122

Circuit Description

The Throttle Position sensor is potentiometer. A 5 volt reference is provided on CKT 605 and ground is provided on CKT 808. The TP sensor signal CKT 417 varies between ground and 5 volts based on the position of the throttle plates. At low throttle angle, the TP sensor signal voltage is low. The PCM uses TP sensor information to determine idle, Wide Open Throttle (WOT), deceleration enleanment and acceleration enrichment. DTC P0122 sets when the PCM detects a TP sensor signal that is too low. The PCM tests the TP sensor feedback every 100 ms. If the TP sensor reading is 0.1 volts or less, such as when the signal is open or shorted to ground, the PCM sets DTC P0122.

Conditions for Running the DTC

Engine speed 600 RPM or greater.

Conditions for Setting the DTC

The TP sensor reading is 0.1 volts or less.

Action Taken When the DTC Sets

^ PCM disables the torque converter clutch.
^ PCM calculates a TP sensor value based on MAP and engine speed inputs.
^ PCM disables fourth gear.
^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
^ The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records.

Conditions for Clearing the MIL/DTC

^ The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.
^ A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.
^ A History DTC will clear after forty consecutive warm-up cycles with no failures of any emission related diagnostic test.
^ Use a scan tool to clear DTCs.
^ Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended.

If fault is not present perform Powertrain Ground Check and also review Failure Rec. to determine conditions under which and how long ago the DTC set. Component Tests and General Diagnostics

Test Description

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

2. With TP sensor or wiring open, TP sensor display will read 0.1 volts or less.
3. Checking for open TP sensor or open wiring. If the display value stays less than 4.96 volts with the TP sensor terminals A and C jumpered together, the problem is in the wiring.
4. Voltage should be greater than 0.5 volt if CKT 605 is not open or shorted to ground.
5. If voltage at TP sensor connector terminal A is 4.5 volts or more, the TP Sensor Signal circuit could be shorted to ground.
6. Use the MAP display to determine if a 5 volt reference problem exists.
7. If there is high resistance, the TP Sensor Signal circuit could be open. If low resistance exists the PCM may be faulty.
8. Checking the 5 volt reference feed to the TP sensor. The 5 volt reference circuits are shared inside the PCM. A short to ground on any 5 volt circuit will cause several other 5 volt circuits to be grounded also. A short to ground may also occur in one of the components that uses a 5 volt reference. Check for shorted components before replacing a PCM.