1994 Geo Metro XFiFACTORY 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
0 (-18) 14,650
19 (-7) 8100
39 (4) 4780
70 (21) 2350
100 (38) 1250
160 (71) 400
210 (99) 190
INTAKE AIR TEMPERATURE (IAT) SENSOR RESISTANCE

Temperature - °F (°C) Ohms
0 (-18) 14,650
19 (-7) 8100
39 (4) 4780
70 (21) 2350
100 (38) 1250
160 (71) 400
210 (99) 190

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.

OXYGEN SENSOR HEATER RESISTANCE

Application Ohms
Upgraded Emissions (1)
(1) A low resistance should be present.
THROTTLE POSITION (TP) SENSOR RESISTANCE

Application Ohms
Standard Emissions
Between Terminals 1 & 2 (1) 0-5000
Between Terminals 1 & 2 (2) Infinity
Between Terminals 1 & 2 (3) 0-5000
Between Terminals 1 & 3 (3) 240-1140
Between Terminals 1 & 3 (4) 3170-6600
Between Terminals 1 & 4 4370-8130
Upgraded Emissions (5)
(1) With .012" (.30 mm) feeler gauge installed between throttle stop screw and lever.
(2) With .035" (.89 mm) feeler gauge installed between throttle stop screw and lever.
(3) Throttle valve at idle position.
(4) Throttle valve at fully open position.
(5) For information on TP sensor, see THROTTLE POSITION (TP) SENSOR in ADJUSTMENTS ARTICLE.

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 (Standard Emissions)
G92F26646Courtesy of GENERAL MOTORS CORP.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

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  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
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