P2127

Wiring Diagram:

APP Sensor 2 Circuit Low Voltage:

P2127- APP SENSOR 2 CIRCUIT LOW VOLTAGE
The accelerator pedal assembly contains two accelerator pedal position (APP) sensors with two independent 5 volt supplies, two independent grounds, and two independent signal circuits that vary resistance according to chances in accelerator pedal position. The ECM measures the signal voltage from each APP sensor, which are reduced values of the ECM 5 volt references. As the accelerator pedal moves from the rest to full position, the voltage on APP sensor 1 signal increases from 0.98 to 3.68 volts (+/-0.1), while the voltage on APP sensor 2 signal increases from 0.49 to 1.84 volts (+/-0.1). The ECM monitors each APP signal circuit for faults as well as a performing a comparison check between the sensor 1 and 2 signals. DTC P2127 will set if APP sensor 2 signal voltage at the ECM is below the calibrated voltage value.

DTC PARAMETERS
DTC P2127 will set if APP sensor 2 signal voltage is less than 0.33 volts when:
^ Condition exists for longer than 140 ms
^ Accelerator pedal position must be changing
^ Battery voltage is greater than 7.0 volts
^ Ignition is On

DTC P2127 diagnostic runs continuously once the above conditions have been met.

P2127 is a type A DTC

NOTE: The MIL will illuminate 5 seconds after the DTC has been set with the fault still occurring.

DIAGNOSTIC AIDS
To locate an intermittent problem, use Scan tool to monitor APP SENSOR 2 voltage with ignition On, engine Off.

Wiggling wires while watching for a change in APP SENSOR 2 voltage may locate the area where an open or short to ground in the wiring may exist.

An intermittent open in APP sensor 2 can set this DTC. Press accelerator pedal very slowly from the rest to full position, while using Scan tool to monitor APP SENSOR 2. Watch for a sharp change in voltage. which would indicate an open.

If an APP sensor 2 signal circuit fault is detected, the ECM will default to one of the two limp home modes (limited pedal range with slow acceleration) and sensor 1 will be used. NOTE: The ECM will remain in this condition for the entire ignition cycle even is the fault is corrected.

Circuit 486 (TP sensor I/P sensor 2) and circuit 1274 (APP sensor 2) share the same 5 volt reference supply (5 volt Ref-B).