Service Engine Soon Light???

[Rauder]

Guys,

I am posting this for a buddy of mine. He has a 87 GN, its his daily driver and had a problem with his Speedometer cable (squeeking and locking up). He disconnected from the transmission and now his Service Engine Soon light came on. He wants to know will this cause any damage to the computer or the car while driving with the light on.

Any Thoughts??

 

[DavzGN]

It won't damage the computer. The light is lit because the Vehicle Speed Sensor (VSS) is disconnected. This will cause worse gas mileage because the torque converter won't lock. I'm not sure what other problems lack of VSS signal will cause, it depends on the chip being used. It could cause damage to the car if something else goes wrong and the check engine light won't turn on because it is already on because of the VSS error.

HTH
David

 

[bmackinnon]

It won't damage the computer. The light is lit because the Vehicle Speed Sensor (VSS) is disconnected. This will cause worse gas mileage because the torque converter won't lock. I'm not sure what other problems lack of VSS signal will cause, it depends on the chip being used. It could cause damage to the car if something else goes wrong and the check engine light won't turn on because it is already on because of the VSS error.

HTH
David

Well, the VSS isn't 'disconnected', however the ecm is receiving an 'off-normal' (0 mph) signal from the VSS, given conditions from other sensors, causing the SES lite. However, the substance of Dave's info is correct. Transmission shift points, timing and fueling maps, etc. are all somewhat dependent on the VSS. Your friend needs to lube the speedo cable (or replace it) and reconnect it so the car will perform properly. It's not too difficult, here's a nice, detailed little procedure, courtesy of GNTTYPE.org:
Speedometer Cable Maintenance
Hope this helps... :smile: