1990 Geo Tracker LSi, AutomaticFACTORY OEM SERVICE PROCEDURE

Engine Controls - Sensor Operating Range Charts: Introduction: Notes

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: All voltage tests should be performed with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure.
COOLANT TEMPERATURE SENSOR RESISTANCE

Temperature °F (°C) Resistance Ohms
-40 (-40) 100,700
0 (-18) 25,000
20 (-7) 13,500
40 (4) 7,500
68 (20) 3,400
100 (38) 1,800
160 (70) 450
212 (100) 185
EGR TEMPERATURE SENSOR RESISTANCE (CA ONLY)

Temperature °F (°C) Resistance Ohms
68 (20) 214,000-313,000
104 (40) 90,900-126,000
140 (60) 42,100-55,500
176 (80) 21,100-26,500
212 (100) 11,200-13,600
MAP SENSOR VOLTAGE TEST

Altitude Feet (Meters) (1) Signal Voltage
Below 1,000 (304) 3.8-5.5
1,000-2,000 (304-610) 3.6-5.3
2,000-3,000 (610-914) 3.5-5.1
3,000-4,000 (914-1219) 3.3-5.0
4,000-5,000 (1219-1524) 3.2-5.8
5,000-6,000 (1524-1829) 3.0-4.6
6,000-7,000 (1829-2133) 2.9-4.5
7,000-8,000 (2133-2438) 2.8-4.3
8,000-9,000 (2438-2473) 2.6-4.2
9,000-10,000 (2473-3048) 2.5-4.0
(1) Measure voltage at appropriate ECU terminals. See WIRING DIAGRAMS .
MANIFOLD AIR TEMPERATURE (MAT) SENSOR RESISTANCE TEST

Temperature °F (°C) (1) Resistance Ohms
-40 (-40) 100,700
0 (-18) 25,000
20 (-7) 13,500
40 (4) 7,500
68 (20) 3,400
100 (38) 1,800
160 (70) 450
212 (100) 185
(1) Measure resistance across sensor terminals.
OXYGEN SENSOR VOLTAGE TEST

Condition (1) Volt
Lean .1
Rich .9
(1) Engine running in closed loop.
THROTTLE POSITION SENSOR (TPS) RESISTANCE TEST

Condition Resistance (Ohms)
Between Terminals C-D (1)
At Idle (2) 0-500
At Wide Open Throttle Infinite
Between Terminals A-D (1) 3,500-6,500
Between Terminals B-D (1)
At Idle (2) 0-2,000
At Wide Open Throttle 2,000-6,500
(1) See Fig 1 for terminal identification.
(2) To position throttle valve at idle, apply approximately 18 in. Hg vacuum to throttle opener valve.
Fig 1: Identifying Throttle Position Sensor Terminals
G121570Courtesy of GENERAL MOTORS CORP.
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