I drive a 93 GMC Sonoma p/u. I drove out of town and noticed that the radio was not working. Next the service engine soon idiot light lit up. Once on the highway, the spedometer was not working. Hmmmm
It is possible that there may be a battery/charging system problem (in which case, the next step will be that the engine will not run). Then again, you may have separate problems. The radio not working and the Check Engine light turning on might not be related at all. However, a failed Vehicle Speed Sensor (VSS) or open/shorted VSS circuit would make the speedometer quit working AND cause the Check Engine light to come on.
Proper diagnosis is the only way to find out for sure.
I would BEGIN by performing a thorough battery/charging system test. Then you need to scan your onboard computer to find out WHY it has turned the Check Engine light on. This should be done BEFORE the battery cables are disconnected for any kind of charging system or battery repair. Once the cables are disconnected, the computer memory will be lost and you will not get any codes to tell you why the computer has turned the light on. You MAY have a charging system-related code like "Voltage Low At Module" or you MAY have a totally different code like "VSS Circuit Open or Shorted". You need to find this out before making ANY repairs.
However, if the charging system tests faulty and/or you have any charging system fault codes, ALL fault codes should be recorded and the battery/charging system problem needs to be dealt with FIRST. (you cannot trust what the computer is telling you if there are charging system faults.) If after this, any symptoms persist, diagnosis of any other fault codes retrieved should be performed.
If all engine control problems are resolved and your radio still does not work, you need to diagnose your radio circuits as a separate problem.
Jan 02, 2012 |
Cars & Trucks