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Troubleshooting Flow Chart Pages
No ALDL data, Check engine light on steady
Engine cranks but does not run
Hard Start (Cold Start Valve circuit test)
Code 14 (Coolant Temp. Sensor) High Temp. indicated
Code 15 (Coolant Temp. Sensor) Low Temp. indicated
Code 21 (TPS) High voltage indicated
Code 22 (TPS) Low voltage indicated
Code 23 (MAT) Low Temp. indicated
Code 24 Vehicle Speed Sensor (VSS)
Code 25 (MAT) High Temp. indicated
Code 33 Mass Air Flow (MAF) gm/sec high
Code 33 Manifold Absolute Pressure (MAP) high v., low vacuum
Code 34 Mass Air Flow (MAF) gm/sec low
Code 34 Manifold Absolute Pressure (MAP) low v., high vacuum
Code 36 MAF burn off diagnosis
Code 42 Electronic Spark Timing (EST) diagnosis
Code 43 Electronic Spark Control (ESC) diagnosis 1985-89 TPI
Code 43 Electronic Spark Control (ESC) diagnosis 1990-92 TPI
Code 44 O2 sensor, lean exhaust indicated
Code 45 O2 sensor, rich exhaust indicated
Code 46 VATS (Vehicle Anti-Theft System)
Codes 51, 52, 55- ECM related error codes
Code 54 Fuel pump low voltage indicated