GM Service Manual Online
For 1990-2009 cars only

Motor Speed Test

Tools Required

J 39916-A Audio System Diagnostic Audio Kit

The diagnostic tape in J 39916-A contains a two minute time period section marked for the purpose of checking the cassette tape motor playing speed. This portion of the diagnostic tape can be used to verify concerns of abnormal sound from the cassette tape player. In some cases, improper tape motor speed can cause audio abnormalities.

The tape motor speed is within tolerance, if the time taken for this test is between one minute and fifty-six seconds to two minutes and one second.