AP/IVS Pedal Position Sensor/Idle Validation Switch

Signal Functions

The Accelerator Pedal Position Sensor (AP) is a potentiometer type sensor which, when supplied with a 5 volt reference signal from the Powertrain Control Module (PCM), provides a linear analog voltage signal that indicates the driver's demand for power.

The Idle Validation Switch (IVS) is a 0/12 volt switch that provides the PCM with a redundant signal to verify when the pedal is in the idle position.

Fuel Quantity and Timing Control

The AP signal is used in calculating desired fuel quantity and injector timing.

Injection Control Pressure

Accelerator pedal position is one of the controlling variables in the calculation of desired injection control pressure.

Fault Detection/Management

Any detected malfunction of the AP or IVS sensor circuit will illuminate the CHECK ENGINE lamp.

An AP signal that is detected out of range high or low by the PCM will cause the engine to ignore the AP signal and will only allow the engine to operate at low idle only.

If a disagreement in the state if IVS and AP if detected by the PCM and the PCM can not discern if it is an AP or IVS fault or if it is and AP fault, the engine will be allowed to operate at low idle only.

Connector Checks to Ground (B-) (Check with Sensor Connector Disconnected and Ignition Key Off, All Accessories Off)

Test Points	Spec.	Comments
1 to Grd.	< 5 ohms	Resistance to grd. (B-) check w/key off, > than 5 ohms harness is open. -AP sig. Grd.
2 to Grd.	>1000 ohms	Resistance less than 1000 ohms indicates a short to ground. -AP signal
3 to Grd.	>1000 ohms	Resistance less than 1000 ohms indicates a short to ground. -AP VRef
A to Grd.	>1000 ohms	Resistance less than 1000 ohms indicates a short to ground. -IVS signal

Connector Voltage Checks (Check with Sensor Connector Disconnected and Ignition Key On)

Test Points	Spec.	Comments
1 to Grd.	0 - .25 volts	Signal ground no voltage expected.
2 to Grd.	0 - .25 volts	If greater than .25 volts signal circuit is shorted to Vref or battery. -AP signal
3 to Grd.	5 ± .5 volts	VRef check key on, if VRef not present check open/short to grd #91 to B, see VRef circuit.
A to Grd.	0-.25 volts	If greater than .25 volts signal circuit ground wire is shorted to Vref or battery.
B to Grd.	12 ± 1.5 volts	<10.5v check for poor connection, 0 v check for open/short to grd circuit or blown fuse.

Harness Resistance Checks (Check with breakout box installed on engine harness only)

Test Points	Spec.	Comments
#91 to 1	< 5 ohms	Resistance from 104 pin connector to harness connector - Signal Ground
#89 to 2	< 5 ohms	Resistance from 104 pin connector to harness connector - AP Signal
#90 to 3	< 5 ohms	Resistance from 104 pin connector to harness connector - VRef
#5 to A	< 5 ohms	Resistance from 104 pin connector to harness connector - IVS Signal
V IGN. to B	< 5 ohms	Resistance from V IGN, power to harness connector

Operational Voltage Checks (Check with breakout box installed key "ON")

Position	AP Test Points (+) #89 to (-) #91	IVS Test Points (+) #5 to (-) #91	Comments
	Voltage	Voltage
Low Idle	.37 to 1.4 V	< .25 volts	Minimum IVS transition point .2 volts above base idle voltage.
High Idle	3 to 4.5 V	12 ± 1.5 volts	Maximum IVS transition point @ 1.6v of AP signal

Diagnostic Trouble Code Descriptions

0122 AP signal was less than 0.37 volts for more than 0.5 seconds*
0123 AP signal was greater than 4.56 volts for more than 0.5 seconds*
0221 AP and IVS disagree
0220 PCM did not receive IVS transition