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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Diagnosis - A/T >> Diagnostic Code Charts (Trucks) >> Code 25, Mat Sensor Temp. High - 1992 2.5L & 4.3L Turbo >> Diagnostic Aids

Diagnostic Aids

A scan tester reads temperature of air entering engine and should read close to ambient air temperature when engine is cold, and rises as underhood temperature increases. Carefully check harness and connections for possible short to ground in circuit No. 472.

Temperature to resistance value scale may be used to test sensor at various temperature levels to evaluate the possibility of malfunctioning sensor. This condition could cause a driveability problem.

Fig 1: Code 25, MAT Sensor Circuit Diagram (1992 2.5L & 4.3L Turbo)
G92E13718Courtesy of GENERAL MOTORS CORP.