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Vehicle Speed Sensor (Metro)

  1. Check speedometer operation. If speedometer operates correctly, proceed to step 2). Repair or replace speedometer if speedometer is not operating properly.
  2. Disconnect connectors C1 (right side) and C2 (left side) from instrument cluster. Using ohmmeter, measure resistance from Black/Blue wire of C1 connector and ground. If resistance is less than .3 ohms, proceed to step 3). If resistance is greater than .3 ohms, repair Black/Blue wire between instrument cluster and ground connection, located left of cigarette lighter and lower support on instrument panel.
  3. Turn ignition on. Using voltmeter, measure voltage from Yellow/Green wire of connector C2 to ground. If voltage is greater than 5 volts, proceed to step 6). If voltage is less than 5 volts, measure voltage at Yellow/Green wire of ECM. The ECM is located under left side of dash.
  4. If voltage is greater than 5 volts, repair open in Yellow/Green wire between ECM and instrument panel. If voltage is less than 5 volts, proceed to step 5).
  5. Turn ignition off. Disconnect 18-pin connector from ECM, located under left side of dash. Using ohmmeter, measure resistance from Yellow/Green wire of connector to ground. If continuity is present, repair short to ground in wiring between ECM and instrument cluster. If short is not present, replace ECM.
  6. Disconnect speedometer cable from speedometer. Connect ohmmeter across terminals No. 1 and 2 of vehicle speed sensor. See Fig 1 . Measure resistance while rotating speedometer head.
  7. If resistance drops to less than 5 ohms, 4 times per revolution, replace ECM. If resistance DOES NOT drops to less than 5 ohms, 4 times per revolution, replace speedometer.
Fig 1: Identifying Vehicle Speed Sensor Terminals (Metro & Prizm)
G90D17940Courtesy of GENERAL MOTORS CORP.
NOTE: Following procedure applies if Code 42 is stored in ECM memory or incorrect input from vehicle speed sensor is suspected.