DTC P2138
The accelerator pedal position (APP)
sensor is made up of 2 sensors that are housed inside one assembly. The
engine control module (ECM) supplies a separate 5-volt reference circuit and a
low reference circuit for each of the sensors. The 5-volt reference for APP
sensor 1 is supplied from the same source in the ECM as the 5-volt reference
for the mass air flow (MAF) sensor and the fuel tank pressure (FTP) sensor. The
5-volt reference voltage for all of the sensors is supplied on separate ECM
terminals, but the terminals are connected internally to a voltage supply. The
APP sensor 1 sends a signal from the sensor to the ECM indicating the
accelerator pedal position. The ECM actuates the throttle plates based on this
information. If the ECM detects that the APP sensors are not within a predicted
value from each other, DTC P2138 sets.
This diagnostic procedure supports
the following DTC:
DTC P2138 Accelerator Pedal
Position (APP) Sensor 1-2 Correlation
Conditions
for Running the DTC
|
• |
DTCs P0601, P0602, P0603, P0604,
P0606, P0607, P0641, P0651, P2120, P2122, P2123, P2125, P2127, P2128 are not
set. |
|
• |
The ignition is ON. |
|
• |
DTC P2138 runs continuously
once the above conditions are met. |
Conditions
for Setting the DTC
The ECM detects that the difference
between APP sensor 1 and APP sensor 2 is more than the predicted value
for less than 1 second.
Action
Taken When the DTC Sets
Conditions
for Clearing the MIL/DTC
|
• |
The control module turns OFF the
malfunction indicator lamp (MIL) after 3 consecutive ignition cycles
that the diagnostic runs and does not fail. |
|
• |
A current DTC, Last Test Failed,
clears when the diagnostic runs and passes. |
|
• |
A history DTC clears after
40 consecutive warm-up cycles, if no failures are reported by this or
any other emission related diagnostic. |
|
• |
Clear the MIL and the DTC with a
scan tool. |
|
Step |
Action |
Values |
Yes |
No |
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Schematic
Reference: Engine
Controls Schematics Connector
End View Reference: Engine
Control Module (ECM) Connector End Views or Engine
Controls Connector End Views |
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Did you perform the Diagnostic
System Check - Vehicle? |
-- |
Go
to Step 2
|
Go to Diagnostic
System Check - Vehicle in Vehicle DTC Information |
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Observe the DTC information with a
scan tool. Is DTC P0101, P0121, P0122,
P0123, P0222, P0223, P2120, P2122, P2123, P2125, P2127, P2128 also set? |
-- |
Go to Diagnostic
Trouble Code (DTC) List - Vehicle in Vehicle DTC Information |
Go
to Step 3
|
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Is the resistance more than the
specified value for any circuit? |
5 ohms |
Go
to Step 7
|
Go
to Step 4
|
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Test the signal circuit of APP
sensor 1 for a short to the signal circuit of the APP sensor 2.
Refer to Circuit
Testing and Wiring
Repairs in Wiring Systems. Did you find and correct the
condition? |
-- |
Go
to Step 9
|
Go
to Step 5
|
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Test for an intermittent and for a
poor connection at the APP sensor. Refer to Testing
for Intermittent Conditions and Poor Connections and Connector
Repairs in Wiring Systems. Did you find and correct the
condition? |
-- |
Go
to Step 9
|
Go
to Step 6
|
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|
Test for an intermittent and for a
poor connection at the ECM. Refer to Testing
for Intermittent Conditions and Poor Connections and Connector
Repairs in Wiring Systems. Did you find and correct the
condition? |
-- |
Go
to Step 9
|
Go
to Step 8
|
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|
Repair the high resistance in the
circuit that measure above the specified value. Refer to Wiring
Repairs in Wiring Systems. Did you complete the repair? |
-- |
Go
to Step 9
|
-- |
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Replace the APP sensor. Refer to Accelerator
Pedal Position (APP) Sensor Replacement . Did you complete the replacement? |
-- |
Go
to Step 9
|
-- |
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Did the DTC fail this ignition? |
-- |
Go
to Step 2
|
Go
to Step 10
|
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Observe the Capture Info with a
scan tool. Are there any DTCs that have not
been diagnosed? |
-- |
Go to Diagnostic
Trouble Code (DTC) List - Vehicle in Vehicle DTC Information |
System
OK |
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