GM 96055449 Sensor

Most components in 1989 through 1991 Geo Metro models have an extended warranty coverage from the government which makes it difficult to perform component checks or replacements during the warranty period. Both sensors found in electrical position determine exhaust gas oxygen levels within the exhaust manifold and catalytic converter which detects emission levels respectively where circuit failures produce code 13. A failure within the TBI unit coolant temperature sensor thermistor will trigger a code 14 or 15 while a check requires resistance tests with an ohmmeter and replacement with Teflon tape or thread sealant to stop leaks. A failure in the manifold air temperature (MAT) sensor located in the air cleaner housing produces a code 24 which should be diagnosed by a dealer. A faulty manifold absolute pressure sensor cannot be repaired thus it requires complete unit replacement because it transforms the manifold pressure fluctuations into an electronic signal for fuel control through ECM. Manual transaxle cars use a throttle switch (TS) to check throttle valve angle whereas automatic transaxle vehicles utilize a throttle position sensor (TPS) to accomplish the same function. Both devices trigger error codes 21 or 22 that demand professional diagnostics for proper fix. A failure of the vehicle speed sensor (VSS) which is integrated with the speedometer causes a pulsing voltage signal to the ECM for speed calculation and produces error code 24. This diagnosis requires professional attention from a dealer. Engine speed calculation and device control operations derive from the crank angle sensor which exists as a component of the distributor to produce alternating voltage pulses.