• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provide an overview of each diagnostic category. |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
Accelerator Pedal Position (APP) Sensor 1 5-Volt Reference Circuit | P0343, P0348, P0368, P0393, P0652, P2122 | P2122, P2138 | P2122 | P0653, P2138, P2123 | P0652, P0653, P2138 |
Accelerator Pedal Position (APP) Sensor 2 5-Volt Reference Circuit | P0122, P0222, P0335, P0642, P0698, P0700 | P2127, P2138 | P2127 | P0123, P0221, P0699, P2138, P2128, P0700 | P0698, P0699, P2138 |
Accelerator Pedal Position (APP) Sensor 1 Signal | P2122 | P2138 | P2122 | P2123 | P2138 |
Accelerator Pedal Position (APP) Sensor 2 Signal | P2127 | P2138 | P2127 | P2128 | P2138 |
Accelerator Pedal Position (APP) Sensor 1 Low Reference | -- | P2123, P2138 | P2123 | -- | P2138 |
Accelerator Pedal Position (APP) Sensor 2 Low Reference | -- | P2127, P2138 | P2128 | -- | P2138 |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: The engine is operating at idle. Parameter Normal Range: APP Sensor 1 0%/1 Volts Parameter Normal Range: APP Sensor 2 0%/0.5 Volts | |||
5-Volt Reference | 0%/0.00 Volts | 0%/0.00 Volts | 0%/4.98 Volts |
APP Sensor 1 Signal | 0%/0.00 Volts | 0%/0.00 Volts | 0%/4.98 Volts |
APP Sensor 2 Signal | 0%/0.00 Volts | 0%/0.00 Volts | 0%/4.98 Volts |
APP Sensor 1 Low Reference | -- | 0%/4.98 Volts | -- |
APP Sensor 2 Low Reference | -- | 0%/4.98 Volts | -- |
The accelerator pedal assembly contains two accelerator pedal position (APP) sensors. The APP sensors are mounted in the pedal assembly and are not serviceable. The APP sensors provide a signal voltage that changes relative to the position of the accelerator pedal. The engine control module (ECM) supplies a separate 5-volt reference and low reference circuit for each of the APP sensors.
The APP sensor 1 signal voltage increases as the pedal is depressed, from approximately 1.0 volt at rest to approximately 4 volts when fully depressed. The APP sensor 2 signal voltage increases as the pedal is depressed, from approximately 0.5 volt at rest to approximately 2 volts with the accelerator pedal fully depressed.
• | The ignition is ON or the engine is operating. |
• | The ignition voltage is more than 7 volts. |
• | The DTCs run continuously once the above conditions are met. |
The APP sensor 1 voltage is less than 0.86 volts for more than 200 milliseconds.
The APP sensor 1 voltage is more than 4.82 volts for more than 200 milliseconds.
The APP sensor 2 voltage is less than 0.63 volts for more than 200 milliseconds.
The APP sensor 2 voltage is more than 4.82 volts for more than 200 milliseconds.
• | The ECM detects that the voltage difference between APP sensor 1 and 2 is more than 0.46 volts. |
• | The ECM detects that the voltage difference between APP sensor 1 and 2 is more than 0.58 volts with a partially pressed pedal. |
• | The ECM detects that the voltage difference between APP sensor 1 and 2 is more than 3.4 volts with a fully pressed pedal. |
• | Any of the above conditions exist for more than 240 milliseconds. |
DTCs P2122, P2123, P2127, P2128, and P2138 are Type A DTCs.
DTCs P2122, P2123, P2127, P2128, and P2138 are Type A DTCs.
Test the current out-put of the 5-volt reference circuits if you suspect high resistance in the circuit. The current out-put should be greater than 80 mA for APP 1 and greater than 50 mA for APP 2.
Throttle Actuator Control (TAC) System Description
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
⇒ | If a DTC is set, refer to DTC P0652 or P0653 or DTC P0698 or P0699 . |
⇒ | If greater than 5 ohms, test the low reference circuit of the APP sensor for a short to voltage, or an open/high resistance. If the circuit/connections test normal, replace the ECM. |
Important: The 5-volt reference circuit voltage can be within the specified range with a high resistance in the circuit. If this condition is suspected, refer to Diagnostic Aids.
⇒ | If less than the specified value, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit/connections test normal, replace the ECM. |
⇒ | If greater than the specified value, test the 5-volt reference circuit for a short to voltage. If the circuit/connections test normal, replace the ECM. |
⇒ | If greater than the specified value, test the signal circuit of the applicable APP sensor for a short to voltage. If the circuit/connections test normal, replace the ECM. |
⇒ | If less than the specified value, test the appropriate signal circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM. |
⇒ | If both APP sensor voltage parameters display greater than 4.8 volts test the signal circuits of the APP sensors for a shorted together condition. If the circuit/connections test normal, replace the ECM. |
⇒ | If the voltage is not within the specified range or is erratic on either APP sensor, replace the accelerator pedal assembly. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for engine control module replacement, setup, and programming |