Engine Controls - Sensor Operating Range Charts: Introduction

Sensor operating range information can help determine if a sensor is out of calibration. Although an out-of-calibration sensor may not set a trouble code, it may cause driveability problems.

NOTE: Unless stated otherwise in test procedure, perform all voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance.

COOLANT TEMPERATURE (ECT) SENSOR RESISTANCE TEST ⁽¹⁾

Temperature - °F (°C)

Ohms

-4 (-20)

15,000-18,000

68 (20)

2000-3000

176 (80)

300-500

⁽¹⁾	Measure resistance across sensor terminals.

FUEL TANK PRESSURE SENSOR ⁽¹⁾

Absolute Pressure

Volts

-2 In. Hg

0.5

Zero In. Hg

2.5

+2 In. Hg

4.5

⁽¹⁾	California emissions.

INTAKE AIR TEMPERATURE (IAT) SENSOR RESISTANCE TEST ⁽¹⁾

Temperature - °F (°C)

Ohms

-4 (-20)

15,000-18,000

68 (20)

2000-3000

176 (80)

300-500

⁽¹⁾	Measure resistance across sensor terminals.

MAP SENSOR VOLTAGE TEST ⁽¹⁾

Vacuum Applied - In. Hg

Volts

2.8-3.0

2.3-2.5

1.8-2.0

1.3-1.5

0.8-1.0

0.3-0.5

⁽¹⁾	Measure voltage at appropriate ECM terminals. See the WIRING DIAGRAMS article in ENGINE PERFORMANCE.

EGR LIFT SENSOR VOLTAGE TEST ⁽¹⁾

Position

Volts (Approximate)

Fully Closed

1.2

Fully Open

4.3

⁽¹⁾	Measure voltage at appropriate ECM terminals. See the WIRING DIAGRAMS article in ENGINE PERFORMANCE. Voltage should increase smoothly as vacuum is applied.

OXYGEN SENSOR VOLTAGE TEST ⁽¹⁾

Condition

Volts

Lean

Less Than 0.3

Rich

Greater Than 0.6

⁽¹⁾	Measure voltage between ground and oxygen sensor terminal using a high-impedance DVOM.

THROTTLE POSITION (TP) SENSOR VOLTAGE

Condition		Volts
Throttle Valve
Fully Closed		0.5
Wide Open		4.5

VEHICLE SPEED SENSOR (VSS) TEST ⁽¹⁾

Application

Voltage

VSS

⁽²⁾

⁽¹⁾	Backprobe terminals at sensor.

⁽²⁾	Voltage will fluctuate between zero and 5 volts while rotating drive wheel.