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Home >> Geo >> 1990 >> Tracker Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Self-Diagnostic System >> Retrieving Codes
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Retrieving Codes

  1. Insert spare fuse into diagnostic switch terminal, located in fuse block under left side of dash. Turn ignition switch to ON position. Read trouble code(s). Proceed to CODE CHARTS for diagnosing stored codes.
  2. If no trouble codes are stored, CHECK ENGINE light will flash rapidly on then off until fuse is removed. Count the number of flashes and look for pauses in flashing to ensure no trouble codes are overlooked. If trouble codes are stored, code will flash 3 times and the lowest code will be given first.
TROUBLE CODE IDENTIFICATION CHART

Code Circuit Affected Probable Cause
13 Oxygen Sensor Open Circuit
14 Coolant Temp. Sensor High Temp. Indicated
15 Coolant Temp. Sensor Low Temp. Indicated
21 (1) Throttle Switch Both Idle Switch &
Throttle Switch ON 
21 (2) Throttle Position Sensor Signal Voltage High
22 (2) Throttle Position Sensor Signal Voltage Low
23 Manifold Air Temp. Sensor Low Temp. Indicated
24 Vehicle Speed Incorrect Signal Voltage
25 Manifold Air Temp. Sensor High Temp. Indicated
31 MAP Sensor Signal Voltage Low High Vacuum
32 MAP Sensor Signal Voltage High Low Vacuum
41 Ignition Signal No Signal
42 Crank Angle Sensor No Signal
51 (3) EGR System Shorted Circuit
(1) Manual transmission only.
(2) Automatic transmission only.
(3) California vehicles only.
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