DTC P0221 Accelerator Pedal Position (APP) Sensor 2 Circuit Performance. GMC Truck Savana 2000

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2000 🢒 Savana 🢒 Engine 🢒 Engine Controls - 6.5L (L65) 🢒 DTC P0221 Accelerator Pedal Position (APP) Sensor 2 Circuit Performance

Engine Controls Components
Cruise Control, APP Module
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The accelerator pedal position (APP) module provides a voltage signal that changes relative to the accelerator position. There are 3 differently scaled sensors located within the APP module.

Conditions for Running the DTC

•	The ignition voltage is more than 6.4 volts.

•	The engine speed is more than 300 RPM.

•	There are no in range faults for APP 1 or APP 3. The powertrain control module (PCM) checks for high and low voltage faults.

Conditions for Setting the DTC

•	The difference between APP 2 and APP 3 is more than 0.50 volts. The PCM compares pre-scaled voltage that is internal to the PCM.

•	The difference between APP 2 and APP 1 is more than 0.23 volts. The PCM compares the pre-scaled voltage that is internal to the PCM.

•	The conditions were met for 2 seconds.

Action Taken When the DTC Sets

•	The service throttle soon lamp will not illuminate when one APP DTC sets. The PCM will only illuminate the service throttle soon lamp when multiple APP DTCs set.

•	The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Failure Records.

Conditions for Clearing the MIL/DTC

•	A History DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.

•	Use a scan tool in order to clear the DTCs.

There are no driveability issues associated with the APP module unless a DTC is present. The most likely causes of this DTC are faulty connections or the sensor itself. The least likely cause is a powertrain control module (PCM) problem.

An intermittent may be caused by:

•	Faulty connections

•	Rubbed-through wire insulation

•	Broken wire inside the insulation

A scan tool reads the APP 2 position in volts and should read approximately 4.5 volts with the throttle closed and the ignition ON or at idle. The voltage should steadily decrease as the throttle is moved toward wide open throttle (WOT). Also, 90 percent pedal travel is acceptable for correct APP operation. Scan the APP 2 sensor while depressing the accelerator pedal with the engine stopped and the ignition ON. The display should vary from approximately 4.5 volts when the throttle is closed to approximately 1.5 volts when the throttle is held at the WOT position.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

This step determines if there is a good 5-volt reference.

This step will check for an open in the ground circuit.

Step	Action	Value(s)	Yes	No
1	Important: Before clearing any DTCs, use the scan tool Capture Info function in order to save the Freeze Frame and the Failure records for reference. The control module's data is deleted once the Clear Info function is used. Was the Powertrain On-Board Diagnostic (OBD) System Check performed?	--	Go to Step 2	Go to Powertrain On Board Diagnostic (OBD) System Check
2	Turn ON he ignition with the engine OFF. With the throttle closed, observe the APP voltages on the scan tool. Are the APP voltages at the specified values? The values are listed as APP 1, APP 2, and APP 3 respectively.	0.45-0.95 V 4.0- 4.5 V 3.6- 4.0 V	Go to Step 3	Go to Step 4
3	The DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids. If any additional DTCs are stored, refer to the applicable DTC tables first. Are any additional DTCs stored?	--	Go to the applicable DTC table	Go to Diagnostic Aids
4	Disconnect the APP sensor electrical connector. Turn ON the ignition, leaving the engine OFF. With J 39200 DMM connected to ground, probe the APP sensor 5-volt reference circuits at APP harness terminals G, D, and E. Is the voltage more than or equal to the specified value on all of the circuits?	4.75 V	Go to Step 5	Go to Step 6
5	Turn ON the ignition, with the engine OFF. With a J 35616-200 unpowered test lamp connected to B+, probe the APP sensor ground circuits at APP sensor harness terminals A, B, and J. Is the Test lamp ON on all of the circuits?	--	Go to Step 9	Go to Step 8
6	Turn OFF the ignition. Disconnect the PCM and check the 5-volt reference circuit for an open or a short to ground. If the 5-volt reference circuit is open or shorted to ground, repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems. Did you perform a repair?	--	Go to Step 11	Go to Step 7
7	Check the 5-volt reference circuit for a faulty connection at the PCM and the replace terminal if necessary. Refer to Wiring Repairs in Wiring Systems. Did you perform a repair?	--	Go to Step 11	Go to Step 10
8	Turn OFF the ignition. Disconnect the PCM and check for an open sensor ground circuit to the PCM. If you find a problem, repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems. Did you perform a repair?	--	Go to Step 11	Go to Step 10
9	Replace the APP module. Refer to Accelerator Pedal Position Module Replacement . Is the action complete?	--	Go to Step 11	--
10	Important: The new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Is the action complete?	--	Go to Step 11	--
11	Use a scan tool in order to clear the DTCs. Start the engine. Allow the engine to idle until the normal operating temperature is reached. Select DTC and the Specific DTC function. Enter the DTC number that was set. Operate the vehicle within the Conditions for Setting this DTC until the scan tool indicates the diagnostic Ran. Does the scan tool indicate the diagnostic Passed?	--	Go to Step 12	Go to Step 2
12	Does the scan tool display any additional undiagnosed DTCs?	--	Go to the applicable DTC table	System OK