GM Service Manual Online
For 1990-2009 cars only

DTC P1273 Without RPO CTF

Table 1: APP Sensor Position Table
Table 2: DTC P1273 APP sensor 1-3 correlation

Circuit Description

The accelerator pedal position (APP) sensor is mounted on the accelerator pedal control assembly. The sensor is made up of 3 individual sensors within one housing. Three separate signal, low reference, and 5-volt reference circuits are used in order to interface the APP sensor with the engine control module (ECM). Each sensor has a unique functionality to determine pedal position as shown in the table below. The ECM uses the APP sensor to determine the amount of acceleration or deceleration desired by the person driving the vehicle via fuel injector control. This DTC sets if the ECM determines an out of range condition with the APP sensor.

APP Sensor Position Table

APP Sensor

Actual Pedal Position

% Depressed as Observed on a Scan Tool

Voltage as Observed on a Scan Tool

1

Pedal at rest

0

.52 - .80

1

Pedal at full travel

100

2.12 - 2.78

2

Pedal at rest

0

4.25 - 4.53

2

Pedal at full travel

100

2.24 - 2.93

3

Pedal at rest

0

3.95 - 4.13

3

Pedal at full travel

100

2.69 - 3.16

Conditions for Running the DTC

    • DTCs P1277, P1278, P1287, P1288, P0641, or P0651 are not set.
    • The ignition switch is in the crank or run position.
    • The ignition voltage is between 7-16 volts.

Conditions for Setting the DTC

    • APP sensor 1 and APP sensor 3 are more than 10 percent out of range of each other.
    • All of the above conditions present for less than 1 second.

Action Taken When the DTC Sets

    • The control module stores the DTC information into memory when the diagnostic runs and fails.
    • The malfunction indicator lamp (MIL) will not illuminate.
    • If one or more APP sensor DTCs are set for a single APP sensor, the control module will use the remaining two APP sensors to calculate throttle response.
    • If certain multiple APP sensor DTCs are set for more than one APP sensor, the following occurs:
       - The control module commands Reduced Engine Power mode.
       - The APP indicated angle is limited to a predetermined value to limit the amount of throttle control.
    • If all three APP sensors are out of range, the APP indicated angle is limited to 0 percent. The control module only allows the engine to idle.

Conditions for Clearing the DTC

    • A current DTC Last Test Failed clears when the diagnostic runs and passes.
    • Clear the DTC with a scan tool.

DTC P1273 APP sensor 1-3 correlation

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Is DTC P1271 also set?

Go to DTC P1271

Go to Step 3

3

Is DTC P1272 also set?

Go to DTC P1272

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