i have a p1870

Question

i got a 99 GMC Sonoma,the transmission doesn't seem to be slipping, its got 100k on it could it be the sensor is junk?

Answer 1

P1870 Transmission component slipping

This is a "B" type code condition, you do not really feel this at all, What happens is the ECM monitors the engine speed and the transmission outspeed when the TCC is engage the engine speed should match the output speed. This is not a sensor problem but will be a mechanical transmission problem.