Conditions for Setting the DTC: Notes
WARNING: This page is about a different car, the 2003 GMC Yukon XL, 2003 Chevrolet Suburban, and 2003 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
The PCM detects slip in the torque converter clutch and/or the fourth gear clutch pack with the TCC in an apply or locked mode. DTC P1870 sets during the second consecutive trip when one of the following condition occurs: