DTC P2122, P2123, P2127, P2128 or P2138
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DTC P2122, P2123, P2127, P2128 or P2138
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DTC P2122 00
Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage
DTC P2123 00
Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage
DTC P2127 00
Accelerator Pedal Position (APP) Sensor 2 Circuit Low Voltage
DTC P2128 00
Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage
DTC P2138 00
Accelerator Pedal Position (APP) Sensors 1-2 Not Plausible
DTC P2138 38
Accelerator Pedal Position (APP) Sensors 1-2 Not Plausible
Diagnostic Fault Information
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Circuit
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Short to Ground
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High Resistance
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Open
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Short to Voltage
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Signal Performance
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Accelerator Pedal Position (APP) Sensor 1 5 V Reference Circuit
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P0641 00
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P2138 00, P2138 38
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P2122 00
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P0641 00
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-
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Accelerator Pedal Position (APP) Sensor 2 5 V Reference Circuit
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P0651 00
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P2138 00, P2138 38
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P2127 00
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P0651 00, P0190 00
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-
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Accelerator Pedal Position (APP) Sensor 1 Signal
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P2120 00
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P2138 00, P2138 38
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P2122 00
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P0641 00, P2120 00
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P2138 00, P2138 38
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Accelerator Pedal Position (APP) Sensor 2 Signal
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P2125 00
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P2138 00, P2138 38
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P2127 00
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P2128 00
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P2138 00, P2138 38
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Accelerator Pedal Position (APP) Sensor 1 Low Reference
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-
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P2138 00, P2138 38
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P2122 00
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P2123 00
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-
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Accelerator Pedal Position (APP) Sensor 2 Low Reference
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-
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P2138 00, P2138 38
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P2127 00
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P2128 00
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-
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APP Sensor
Circuit
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Short to Ground
|
Open
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Short to Voltage
|
Operating Conditions:
The engine is operating at idle.
Parameter Normal Range:
APP Sensor 1 0.9-1.2 V
Parameter Normal Range:
APP Sensor 2 varies 0.45-0.62 V
|
5 V Reference 1
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0 V
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0 V
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APP 1 2.08 V
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5 V Reference 2
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0 V
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0 V
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APP 2 0.86 V
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APP Sensor 1 Signal
|
0 V
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0 V
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5 V
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APP Sensor 2 Signal
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0 V
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0 V
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5 V
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APP Sensor 1 Low Reference
|
-
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5 V
|
-
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APP Sensor 2 Low Reference
|
-
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5 V
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-
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Circuit/System Description
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The accelerator pedal assembly contains two accelerator pedal position (APP) sensors. The APP sensors are mounted in the pedal assembly and are not serviceable. The APP sensors provide a signal voltage that changes relative to the position of the accelerator pedal. The Engine Control Module (ECM) supplies a separate 5 V reference and low reference circuit for each of the APP sensors.
The APP sensor 1 signal voltage increases as the pedal is depressed, from approximately 1 V at rest to above 4 V when fully depressed. The APP sensor 2 signal voltage increases as the pedal is depressed, from approximately 0.5 V at rest to more than 2 V with the accelerator pedal fully depressed.
Conditions for Running the DTC
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•
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The ignition is ON or the engine is operating.
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•
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The DTCs run continuously when the above conditions are met.
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Conditions for Setting the DTC
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P2122 00
The APP sensor 1 voltage is less than 0.59 V for more than 4 s.
P2123 00
The APP sensor 1 voltage is more than 4.62 V for more than 4 s.
P2127 00
The APP sensor 2 voltage is less than 0.28 V for more than 4 s.
P2128 00
The APP sensor 2 voltage is more than 2.32 V for more than 4 s.
P2138 00 and P2138 38
The ECM detects that the voltage difference between APP sensor 1 and 2 is more than a predetermined value.
Action Taken When the DTC Sets
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DTCs P2122, P2123, P2127, P2128, and P2138 are Type A DTCs.
Conditions for Clearing the DTC
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DTCs P2122, P2123, P2127, P2128, and P2138 are Type A DTCs.
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
for scan tool information
Circuit/System Verification
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1.
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Ignition ON, observe the scan tool APP Sensor parameters. Both readings should be between 0.4-1.5 V.
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2.
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Rapidly depress the accelerator pedal from the rest position to the wide open throttle position and release pedal. Repeat the procedure several times. DTC P2122, P2123, P2127, P2128 or P2138 are not set.
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3.
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Slowly depress the accelerator pedal to wide open throttle position and then slowly return the pedal to closed throttle. Repeat the procedure several times. DTC P2122, P2123, P2127, P2128 or P2138 are not set.
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4.
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Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
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1.
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Ignition OFF, disconnect the harness connector at the B107 Accelerator Pedal Position Sensor.
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2.
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Test for less than 5 Ω of resistance between the appropriate low reference circuit and ground.
|
|
•
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B107 Accelerator Pedal Position Sensor 1 low reference circuit terminal 4
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|
•
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B107 Accelerator Pedal Position Sensor 2 low reference circuit terminal 5
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3.
|
If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance. If the circuits test normal, replace the K20 Engine Control Module.
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4.
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Note
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The 5 V reference circuits are internally and externally connected at the ECM. Other component DTCs may be set. If other DTCs are set, review the electrical schematic and diagnose the applicable circuits and components.
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Ignition ON, test for 4.8-5.2 V between the appropriate 5 V reference circuit and ground.
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|
•
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B107 Accelerator Pedal Position Sensor 1 5 V reference circuit terminal 2
|
|
•
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B107 Accelerator Pedal Position Sensor 2 5 V reference circuit terminal 1
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5.
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If less the specified range, test the 5 V reference circuit for a short to ground or open/high resistance. If the circuits test normal, replace the K20 Engine Control Module.
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6.
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If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuits test normal, replace the K20 Engine Control Module.
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7.
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Verify the appropriate scan tool APP sensor parameter is less than 0.3 V.
|
|
•
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B107 Accelerator Pedal Position Sensor 1 signal circuit terminal 3
|
|
•
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B107 Accelerator Pedal Position Sensor 2 signal circuit terminal 6
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8.
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If greater than the specified range, test the appropriate signal circuit for a short to voltage. If the circuits test normal, replace the K20 Engine Control Module.
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9.
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Install a 3 A fused jumper wire between the appropriate signal circuit and the 5 V reference circuit. Verify the scan tool APP sensor parameter is greater than 4.8 V.
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10.
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If less than the specified range, test the appropriate signal circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the K20 Engine Control Module.
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11.
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If both scan tool APP sensor parameters display greater than the specified range, test the signal circuits for being shorted together condition. If the circuits test normal, replace the K20 Engine Control Module.
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12.
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If all circuits test normal, replace the B107 Accelerator Pedal Position Sensor.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.