DTC P1285 Accelerator Pedal Position (APP) Sensor 3 Circuit. Pontiac Firebird 1999

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 1999 🢒 Firebird 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 DTC P1285 Accelerator Pedal Position (APP) Sensor 3 Circuit

Circuit Description

The Accelerator Pedal Position (APP) sensors are mounted on the accelerator pedal/TAC module assembly. There are three individual Accelerator Pedal Position sensors within one housing. Three separate signal, ground and reference circuits are used which are contained within the Throttle Actuator Control (TAC) Module. The APP sensor signal voltage increases as the Accelerator pedal is depressed. The signal circuits pull to ground within the TAC module.

Conditions for Running the DTC

•	DTCs P0606, P1517, P1518 are not set.

•	The ignition switch is in the crank or run position.

Conditions for Setting the DTC

•	APP sensor #3 voltage is less than 0.68 volts or greater than 4.5 volts.

•	All above conditions met for less than 1 second.

Action Taken When the DTC Sets

•	The PCM will not illuminate the malfunction indicator lamp (MIL).

•	The PCM will store conditions which were present when the DTC set as Failure Records data only. This information will not be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC

•	A History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

•	The DTC can be cleared by using the scan tool Clear Info function.

Diagnostic Aids

Important: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing/replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

•	Corrosion may cause an intermittent fault.

•	For an intermittent condition, refer to Symptoms .

•	If you complete a repair and the DTC is cleared using a scan tool on the same ignition cycle, the default action will not clear until an ignition cycle has occurred.

•	When the accelerator pedal is depressed more than 10% a DTC P1286 will also set.

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When the TAC module detects a problem within the ETC System the PCM receives a message across serial data and more than one ETC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual problem may correct more than one DTC. Keep this in mind when reviewing captured DTC info.

Test Description

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

DTC P1285 - Accelerator Pedal Position (APP) Sensor 3 Circuit Performance

Step	Action	Value(s)	Yes	No
1	Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?	--	Go to Step 2	Go to Powertrain On Board Diagnostic (OBD) System Check
2	Important: If any other DTCs are set, refer to the appropriate DTC first for further diagnosis. Turn ON the ignition, with the engine OFF. With a scan tool, observe the APP sensor 3 voltage parameter. Does the scan tool indicate the voltage within the specified range?	0.5-1.3 V	Go to Step 3	Go to Step 5
3	Fully depress the accelerator pedal. Does the scan too indicate the voltage within the specified range?	2.9-4.0 V	Go to Step 4	Go to Step 5
4	With a scan tool, select Diagnostic Trouble Codes (DTCs). Slowly depress the accelerator pedal to Wide Open Throttle (WOT) and then slowly return it to closed throttle. Does the scan tool indicate this DTC failed this ignition?	--	Go to Step 5	Go to Diagnostic Aids
5	Replace the TAC Module. Refer to Accelerator Pedal Replacement . Did you complete the replacement?	--	Go to Step 6	--
6	Use the scan tool in order to record Fail Records and clear the DTCs. Operate the vehicle within the Fail Records conditions. Does the DTC reset?	--	Go to Step 2	Go to Step 7
7	Does the scan tool indicate any DTCs set that you have not diagnosed?	--	Go to the applicable DTC table	System OK