1994 Geo Prizm Base, AutomaticFACTORY OEM SERVICE PROCEDURE

Engine Controls - Sensor Operating Range Charts: Introduction

Sensor operating range information can help determine if a sensor is out of calibration. An out-of-calibration sensor may not set a trouble code, but 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.
ENGINE COOLANT TEMPERATURE (ECT) SENSOR RESISTANCE

Temperature - °F (°C) Ohms
-4 (-20) 10,000-20,000
32 (0) 4000-7000
68 (20) 2000-3000
104 (40) 900-1300
140 (60) 400-700
176 (80) 200-400
EGR TEMPERATURE SENSOR RESISTANCE

Temperature - °F (°C) Ohms
122 (50) 69,000-88,000
212 (100) 11,000-15,000
302 (150) 2000-4000
INTAKE AIR TEMPERATURE (IAT) SENSOR RESISTANCE

Temperature - °F (°C) Ohms
-4 (-20) 10,000-20,000
32 (0) 4000-7000
68 (20) 2000-3000
104 (40) 900-1300
140 (60) 400-700
176 (80) 200-400

Manifold Absolute Pressure (MAP) Sensor 

For information on MAP sensor, see ENGINE SENSORS & SWITCHES in I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.

THROTTLE POSITION (TP) SENSOR RESISTANCE

Application Ohms
Between Terminals E2 & IDL (3) 0-2300
Between Terminals E2 & IDL (1) Infinity
Between Terminals E2 & VC 4000-8500
Between Terminals E2 & VTA (4) 200-6000
Between Terminals E2 & VTA (2) 3300-10,000
(1) With .035" (.89 mm) feeler gauge installed between throttle stop screw and lever.
(2) Throttle valve at fully open position.
(3) With .016" (.40 mm) feeler gauge installed between throttle stop screw and lever.
(4) With zero clearance between throttle stop screw and lever.

Vehicle Speed Sensor 

For information on vehicle speed sensor, see ENGINE SENSORS & SWITCHES in I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.

Fig 1: Identifying TP Sensor Terminals
G93F78118Courtesy of GENERAL MOTORS CORP.
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