P0122

DTC P0122 Throttle Position (TP) Sensor Diagnostic Chart:

TPS & ECT:

CIRCUIT DESCRIPTION
The Throttle Position (TP) sensor provides a voltage signal that changes relative to throttle blade angle. Signal voltage will vary from 0.2 - 0.74 volt at idle to above 4.0 volts at Wide Open Throttle (WOT).

The TP signal is one of the most important inputs used by the Powertrain Control Module (PCM) for fuel control and for most of the PCM control outputs.

DIAGNOSTIC TROUBLE CODE PO122 WILL SET WHEN
^ Ignition "ON."
^ TP sensor signal voltage is less than 0.16 volt for 4 seconds.

ACTION TAKEN (PCM WILL DEFAULT TO)
If DTC P0122 is set, the PCM will not allow 4th gear, Torque Converter Clutch (TCC) or cruise control operation. The Malfunction Indicator Light (MIL) is illuminated.

If Circuit (CKT) 417 is open or grounded when the vehicle engine is started, a high idle may result. The Tech 1 scan tool may read the following with Circuit (CKT) 417 open or grounded.

^ TP = 0.04 or less.
^ RPM is greater than 1000 in park.
^ Desired idle is 725 RPM.
^ Intake Air Temperature (IAT) counts are greater than 40.
^ MIL "ON," DTC P0122 set.

If the intermittent is repaired without cycling the key "OFF," the scan tool may read the following.

^ TP = 0.42 volt.
^ RPM greater than 1500 in park.
^ Desired idle = 725 RPM.
^ IAC counts greater than 55.
^ MIL "OFF."

DIAGNOSTIC TROUBLE CODE CHART TEST
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Determines if conditions necessary to set DTC P0122 exist.
2. Simulates DTC P0123 (high voltage) If PCM recognizes the high signal voltage and sets DTC P0123, the PCM and wiring are OK.
3. Simulates a high signal voltage. Checks CKT 417 for an open.


DIAGNOSTIC AIDS
The scan tool displays throttle position in volts. Voltage should increase at a steady rate as throttle is moved toward Wide Open Throttle (WOT).

An open or short to ground in CKT 416 or 417 will result in DTC P0122.

Check for:
^ Poor Connection or Damaged Harness - Inspect PCM harness connectors for backed out terminal "BF11" and/or "BE6", improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.
^ Intermittent Test - Monitor TP sensor voltage display while moving related connectors and wiring harness. If the failure is induced, the display will change. This may help to isolate the location of the malfunction.
^ TP Sensor Scaling - Observe TP sensor voltage display while depressing accelerator pedal with engine stopped and ignition "ON." Display should vary from closed throttle TP sensor voltage when throttle closed (0.2 - 0.74 volt) to over 4.0 volts when throttle is held at Wide Open Throttle position.