Diagnostic Instructions

DTC Descriptors

DTC P2122: Accelerator Pedal Position Sensor 1 Circuit Low

DTC P2123: Accelerator Pedal Position Sensor 1 Circuit High

DTC P2127: Accelerator Pedal Position Sensor 2 Circuit Low

DTC P2128: Accelerator Pedal Position Sensor 2 Circuit High

DTC P2132: Accelerator Pedal Position Sensor 3 Circuit Low

DTC P2133: Accelerator Pedal Position Sensor 3 Circuit High

DTC P2138: Accelerator Pedal Position Sensor 1 and 2 Correlation

DTC P2139: Accelerator Pedal Position Sensor 1 and 3 Correlation

DTC P2140: Accelerator Pedal Position Sensor 2 and 3 Correlation

Diagnostic Fault Information

Circuit	Short to Ground	Open	Short to Voltage
APP 1 Sensor 5-Volt Reference	P0192, P02E8, P0409, P0462, P0642, P2453, P2454, P2564	P2122	--
APP 1 Sensor Signal	P2122	P2122	P2123
APP 1 Sensor GND	--	P2123	--
APP 2 Sensor 5-Volt Reference	P0652	P2127	--
APP 2 Sensor Signal	P2127	P2128	P2128
APP 2 Sensor GND	--	P2128	--
APP 3 Sensor 5-Volt Reference	P0698	P2132	--
APP 3 Sensor Signal	P2132	P2133	P2133
APP 3 Sensor GND	--	P2133	--

Typical Scan Tool Data

APP Sensor 1

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: APP 1 varies Parameter Normal Range: 0-5 Volts
APP Sensor 1 5-Volt Reference	0 V	0 V	--
APP Sensor 1 Signal	0 V	0 V	5 V
APP Sensor 1 Low Reference	--	5 V	--

APP Sensor 2

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: APP 2 varies Parameter Normal Range: 0-5 Volts
APP Sensor 2 5-Volt Reference	0 V	0 V	--
APP Sensor 2 Signal	0 V	5 V	5 V
APP Sensor 2 Low Reference	--	5 V	--

APP Sensor 3

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: APP 3 varies Parameter Normal Range: 0-5 Volts
APP Sensor 3 5-Volt Reference	0 V	0 V	--
APP Sensor 3 Signal	0 V	5 V	5 V
APP Sensor 3 Low Reference	--	5 V	--

APP Sensor Normal Values

APP Sensor	Actual Pedal Position	(%) Depressed as Observed on a Scan Tool	Voltage as Observed on a Scan Tool
APP 1	Pedal at rest	0	0.52-0.80
APP 1	Pedal at full travel	100	2.12-2.78
APP 2	Pedal at reset	0	4.25-4.53
APP 2	Pedal at full travel	100	2.24-2.93
APP 3	Pedal at reset	0	3.95-4.13
APP 3	Pedal at full travel	100	2.96-3.16

Circuit/System Description

The accelerator pedal position (APP) sensor is mounted on the accelerator pedal control assembly. The sensor is made up of three individual sensors within one housing. The engine control module (ECM) uses the APP sensors to determine the amount of acceleration or deceleration desired by the person driving the vehicle via the fuel injector control. The ECM supplies 5 volts to the APP sensor on the 5-volt reference circuit. The ECM also provides a ground on the low reference circuit. The APP sensor provides a signal to the ECM on the APP sensor signal circuit, which is relative to the position changes of the accelerator pedal angle. The ECM monitors the APP sensor signal for voltages outside the normal range of the APP sensor.

Conditions for Running the DTC

P2122 and P2123

P2127 and P2128

P2132 and P2133

P2138

P2139

P2140

Conditions for Setting the DTC

P2122, P2127 and P2132

The ECM detects that the APP sensor signal voltage is less than 0.25 volts.

P2123, P2128 and P2133

The ECM detects that the APP sensor signal voltage is more than 4.75 volts.

P2138

The ECM detects that the APP sensor 1 and 2 are more than 10 percent out of range of each other.

P2139

The ECM detects that the APP sensor 1 and 3 are more than 10 percent out of range of each other.

P2140

The ECM detects that the APP sensor 2 and 3 are more than 10 percent out of range of each other.

Action Taken When the DTC Sets

DTCs P2122, P2123, P2127, P2128, P2132, P2133, P2138, P2139 and P2140 are Type C DTCs.

Conditions for Clearing the DTC

DTCs P2122, P2123, P2127, P2128, P2132, P2133, P2138, P2139 and P2140 are Type C DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Circuit/System Testing

Important: If DTCs P0642, P0643, P0652, P0653, P0698 and P0699 are set, test and repair those DTCs first.

Important: You must perform Circuit/System Verification before proceeding with Circuit/System Testing.

1. Ignition OFF, disconnect the harness connector at the APP sensor. Allow at least 60 seconds for the ECM to power down. Using a DMM, measure the voltage between the 5-volt reference circuit and a low reference circuit.

⇒	If less than 4.8 volts, test the low reference circuit for an open/high resistance.

2. Ignition OFF, test for 4.8-5.2 volts between the applicable APP sensor 5-volt reference circuit and ground.

⇒	If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the control module.

⇒	If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the control module.

3. Install a 3A fused jumper wire between the applicable signal circuit and the applicable 5-volt reference circuit for APP sensor 2 and 3. Verify that the scan tool accelerator position (APP) sensor parameter is greater than 5 volts.

⇒	If less than 4.8 volts, test the applicable signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the control module.

⇒	If more than 5.2 volts, replace the accelerator pedal assembly.

4. Install a 3A fused jumper wire between the applicable signal circuit and the applicable 5-volt reference circuit for APP sensor 1. Verify that the DMM volt meter scan tool accelerator position (APP) sensor parameter is greater than 5 volts.

⇒	If less than 4.8 volts, test the applicable signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the control module.

⇒	If more than 5.2 volts, replace the accelerator pedal assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.