DTC P2120
The accelerator pedal position (APP)
sensors 1 and 2 are located within the accelerator pedal assembly. Each
sensor has the following circuits:
|
• |
A 5-volt reference circuit |
|
• |
A low reference circuit |
|
• |
A signal circuit |
This provides the engine control
module (ECM) with a signal voltage proportional to accelerator pedal movement.
The APP sensors have opposite functionality. APP sensor 1 signal voltage
increases as the pedal is depressed, from below 1 volt at rest to above
2.5 volts when fully depressed. The APP sensor 2 signal voltage decreases
as the pedal is depressed, from 4 volts at rest to less than 1 volt
with the accelerator pedal fully depressed. If the ECM detects that the APP
sensor 1 signal voltage is not within the predicted range, this DTC sets.
This diagnostic procedure supports
the following DTC:
DTC P2120 Accelerator Pedal
Position (APP) Sensor 1 Circuit
Conditions
for Running the DTC
|
• |
The ignition is ON. |
|
• |
The ignition voltage is greater
than 5.23 volts. |
|
• |
DTCs P0601, P0602, P0603,
P0604, P0606, P0607, P0641, P0651 are not set. |
|
• |
DTC P2120 runs continuously
when the above conditions are met. |
Conditions
for Setting the DTC
The APP sensor 1 voltage is
less than 0.3625 volt or more than 2.6 volts for more than
0.4 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 |
|
Schematic
Reference: Engine
Controls Schematics Connector
End View Reference: Engine
Control Module (ECM) Connector End Views or Engine
Controls Connector End Views |
||||
|
1 |
Did you perform the Diagnostic
System Check - Vehicle? |
-- |
Go
to Step 2
|
Go to Diagnostic
System Check - Vehicle in Vehicle DTC Information |
Does the scan tool indicate
voltage less than the first value or greater than the second value? |
0.3625 V 2.6 V |
Go
to Step 4
|
Go
to Step 3
|
|
Does the DTC fail this ignition? |
-- |
Go
to Step 4
|
Go to Intermittent
Conditions |
|
Does the scan tool indicate
voltage at the specified value? |
0 V |
Go
to Step 5
|
Go
to Step 10
|
|
Does the scan tool indicate the
APP sensor 1 voltage at the specified value? |
5 V |
Go
to Step 6
|
Go
to Step 7
|
|
|
Probe the APP sensor low reference
circuit with a test lamp connected to B+. Does the test lamp illuminate? |
-- |
Go
to Step 16
|
Go
to Step 12
|
|
|
Measure the voltage of the APP
sensor 1 5-volt reference circuit with a DMM. Does the DMM indicate voltage at
the specified value? |
5 V |
Go
to Step 9
|
Go
to Step 8
|
|
|
Does the DMM indicate voltage less
than the specified value on the APP sensor 1 5-volt reference circuit? |
5 V |
Go
to Step 13
|
Go
to Step 15
|
|
|
Test the APP sensor 1 signal
circuit for an open or high resistance. Refer to Circuit
Testing and Wiring
Repairs in Wiring Systems. Did you find and correct the
condition? |
-- |
Go
to Step 20
|
Go
to Step 11
|
|
|
Test the APP sensor 1 signal
circuit for a short to voltage. Refer to Circuit
Testing and Wiring
Repairs in Wiring Systems. Did you find and correct the
condition? |
-- |
Go
to Step 20
|
Go
to Step 18
|
|
|
Test the APP sensor 1 signal
circuit for a short to ground. Refer to Circuit
Testing and Wiring
Repairs in Wiring Systems. Did you find and correct the
condition? |
-- |
Go
to Step 20
|
Go
to Step 18
|
|
|
Test the APP sensor 1 low
reference circuit for an open or high resistance. Refer to Circuit
Testing and Wiring
Repairs in Wiring Systems. Did you find and correct the
condition? |
-- |
Go
to Step 20
|
Go
to Step 18
|
|
|
Test the APP sensor 1 5-volt
reference circuit for an open or high resistance. Refer to Circuit
Testing and Wiring
Repairs in Wiring Systems. Did you find and correct the
condition? |
-- |
Go
to Step 20
|
Go
to Step 14
|
|
|
Test the APP sensor 1 5-volt
reference circuit for a short to ground. Refer to Circuit
Testing and Wiring
Repairs in Wiring Systems. Did you find and correct the
condition? |
-- |
Go
to Step 20
|
Go
to Step 18
|
|
|
Test the APP sensor 1 5-volt
reference circuit for a short to voltage. Refer to Circuit
Testing and Wiring
Repairs in Wiring Systems. Did you find and correct the
condition? |
-- |
Go
to Step 20
|
-- |
|
|
Inspect for poor connections at
the accelerator pedal harness connector. 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 20
|
Go
to Step 17
|
|
|
Replace the accelerator pedal
assembly. Refer to Accelerator
Pedal Position (APP) Sensor Replacement . Did you complete the replacement? |
-- |
Go
to Step 20
|
-- |
|
|
Inspect for poor connections at
the engine control module (ECM) harness connector. 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 20
|
Go
to Step 19
|
|
|
Replace the ECM. Refer to Control
Module References in Computer/Integrating Systems for replacement, setup,
and programming. Did you complete the replacement? |
-- |
Go
to Step 20
|
-- |
|
Did the DTC fail this ignition? |
-- |
Go
to Step 2
|
Go
to Step 21
|
|
|
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 |
|