DTC P2122, P2123, P2127, P2128, or P2138 - LDE
Diagnostic Instructions
DTC Descriptors
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
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Accelerator Pedal Position (APP) Sensor 1 5V
Reference
|
P06A3 00, P2122 00
|
P2122 00, P2128 00
|
P06A3 00, P2135 00
|
P2138 00
|
Accelerator Pedal Position (APP) Sensor 2 5V
Reference
|
P0107 00, P0697 00
|
P2127 00, P2138 00
|
P0106 00, P0108 00, P0697 00
|
P2138 00
|
Accelerator Pedal Position (APP) Sensor 1 Signal
|
P2122 00
|
P2122 00, P2138 00
|
P06A3 00, P2123 00
|
P2138 00
|
Accelerator Pedal Position (APP) Sensor 2 Signal
|
P2122 00
|
P2122 00, P2138 00
|
P06A3 00, P2123 00
|
P2138 00
|
Accelerator Pedal Position (APP) Sensor 1 Low Reference
|
-
|
P2123 00, P2138 00
|
-
|
P2138 00
|
Accelerator Pedal Position (APP) Sensor 2 Low Reference
|
-
|
P2128 00, P2138 00
|
-
|
P2138 00
|
Typical Scan Tool Data
APP Sensor 1 and 2
Circuit
|
Short to Ground
|
Open
|
Short to Voltage
|
Operating Conditions: The engine is
operating at idle
Parameter Normal Range: APP
Sensor 1-0.88-1.08 V
Parameter Normal Range: APP
Sensor 2-0.39-0.59 V
|
APP Sensor 1 5V Reference
|
0.00 V
|
0.00 V
|
2.75 V
|
APP Sensor 2 5V Reference
|
0.00 V
|
0.00 V
|
1.35 V
|
APP Sensor 1 Signal
|
0.00 V
|
0.00 V
|
4.98 V
|
APP Sensor 2 Signal
|
0.00 V
|
0.00 V
|
4.98 V
|
APP Sensor 1 Low Reference
|
-
|
4.96 V
|
-
|
APP Sensor 2 Low Reference
|
-
|
4.92 V
|
-
|
Circuit/System Description
The accelerator pedal assembly contains 2 accelerator pedal
position (APP) sensors. The APP sensors are mounted to the
accelerator pedal assembly and are not serviceable. The APP sensors
provide a signal voltage that changes relative to pedal position.
The engine control module (ECM) supplies each APP sensor with a
5 V reference circuit, a low reference circuit, and a signal
circuit.
Both the APP sensors 1 and 2 signal percentages
increase as the pedal is depressed, from approximately 0% at rest
to above 95% when fully depressed.
Conditions for Running the DTC
P2122 00, P2123 00, P2127 00, P2128 00
• |
DTC P06A3 00 or P0697 00 are not
set. |
• |
The ignition is ON or the engine is
operating. |
• |
The ignition voltage is greater than
6 V. |
• |
The ECM is not commanding reduced power. |
• |
The DTCs run continuously when the above
conditions are met. |
P2138 00
• |
DTCs P06A3 00, P0697 00, P2122 00,
P2123 00, P2127 00, or P2128 00 are not set. |
• |
The ignition is ON or the engine is
operating. |
• |
The ignition voltage is greater than
6 V. |
• |
The ECM is not commanding reduced power. |
• |
The DTC runs continuously when the above
conditions are met. |
Conditions for Setting the DTC
P2122 00
The ECM detects that the APP sensor 1 voltage is less than
0.46 V for less than 1 s.
P2123 00
The ECM detects that the APP sensor 1 voltage is greater
than 4.7 V for less than 1 s.
P2127 00
The ECM detects that the APP sensor 2 voltage is less than
0.32 V for less than 1 s.
P2128 00
The ECM detects that APP sensor 2 voltage is greater than
2.64 V for greater than 0.5 s.
P2138 00
The ECM detects that APP sensor 1 and APP sensor 2
disagree greater than 10% for less than 1 s.
OR
The ECM detects that both APP sensor 1 and APP
sensor 2 are 5% greater than the learned minimum position for
less than 1 s.
Action Taken When the DTC Sets
• |
DTCs P2122 00, P2123 00,
P2127, 00 and P2128 00, and P2138 00 are Type C
DTCs. |
• |
DTC P2138 00 is a Type B DTC. |
• |
The ECM commands the throttle actuator control
system to operate in reduced engine power mode. |
Conditions for Clearing the DTC
• |
DTCs P2122 00, P2123 00,
P2127, 00 and P2128 00, and P2138 00 are Type C
DTCs. |
• |
DTC P2138 00 is a Type B DTC. |
Diagnostic Aids
• |
If a shared 5 V reference circuit is shorted
to ground or shorted to a voltage, other 5 V reference
circuits may be affected. |
• |
The scan tool 5 V reference parameter should
display between 4.8-5.2 V. |
• |
A high resistance condition on the accelerator
pedal position (APP) sensor circuits may cause a DTC to set. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Throttle Actuator Control (TAC) System Description
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
- Ignition ON, observe the DTC information with a scan
tool. Verify DTCs P0697 00 or P06A3 00 are not set.
- Ignition ON, observe the scan tool APP Sensor 1
and 2 Indicated parameters. Both parameters should be 0%.
- Observe the scan tool APP Sensor 1 and 2
Agree/Disagree parameter while performing the following tests:
• |
Rapidly depress the accelerator pedal from the
rest position to the wide open throttle position (WOT) and
release pedal. Repeat the procedure several times. |
• |
Slowly depress the accelerator pedal to WOT and
then slowly return the pedal to closed throttle. Repeat the
procedure several times. |
⇒ |
The APP sensor 1 and 2 Agree/Disagree
parameter should display Agree. |
- Observe the DTC information with a scan tool. DTCs
P2122 00, P2123 00, P2127 00, P2128 00, or
P2138 00 should not set.
- 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.
Circuit/System Testing
- Ignition OFF, disconnect the B107 Accelerator
Pedal Position Sensor harness connector at the accelerator pedal
assembly.
- Ignition OFF for 1 min, test for less than
5 Ω between the B107 Accelerator Pedal Position Sensor
low reference circuit terminals listed below and ground:
• |
Low reference circuit terminal 4 |
• |
Low reference circuit terminal 5 |
⇒ |
If greater than the specified range, test the low
reference circuit for a short to voltage, or an open/high
resistance. If the circuit tests normal, replace the
K20 Engine Control Module. |
- Ignition ON, test for 4.8-5.2 V between both
5 V reference circuit terminals listed below and ground:
• |
5 V reference circuit terminal 1 |
• |
5 V reference circuit terminal 2 |
⇒ |
If less than the specified range, test the
5 V reference circuit for a short to ground or open/high
resistance. If the circuit tests normal, replace the
K20 Engine Control Module. |
⇒ |
If greater than the specified range, test the
5 V reference circuit for a short to voltage. If the circuit
tests normal, replace the K20 Engine Control Module. |
- Verify the appropriate APP sensor voltage parameter is
at 0 V.
⇒ |
If greater than the specified range, test the
appropriate signal circuit terminal listed below for a short to
voltage. If the circuit tests normal, replace the K20 Engine
Control Module. |
• |
APP sensor 1 signal circuit
terminal 3 |
• |
APP sensor 2 signal circuit
terminal 6 |
- Install a 3 A fused jumper wire between the
appropriate signal circuit terminal listed below and the 5 V
reference circuit terminal 1 of the appropriate
B107 Accelerator Pedal Position Sensor. Verify the appropriate
APP Sensor voltage parameter is greater than 4.8 V.
• |
APP sensor 1 signal circuit
terminal 3 |
• |
APP sensor 2 signal circuit
terminal 6 |
⇒ |
If less than the specified range, test the signal
circuit for a short to ground or an open/high resistance. If the
circuit tests normal, replace the K20 Engine Control
Module. |
- If all circuits test normal, replace the
B107 Accelerator Pedal Position Sensor.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|