SES Light Illuminated, DTC P1870 - Transaxle Component Slipping (Replace TCC Solenoid)

Some owners may comment that the SERVICE ENGINE SOON light comes on intermittently. The owner may or may not experience a change in vehicle performance. Upon investigation, the technician will find a stored DTC P1870, transaxle component slip.

The TCC solenoid valve may be one of the possible causes for DTC P1870. Sediment internal to the solenoid can keep the check ball from seating properly, resulting in a reduction of apply pressure to the converter clutch. This can be observed on a Tech 2 while at steady speed, with the TCC applied. The slip RPM will increase until DTC P1870 sets.

Use Strategy Based Diagnostics to check for the following:

1. Brake switch misadjusted/defective
2. VSS defective or no signal to PCM
3. PCM not commanding TCC apply
4. Converter clutch valve stuck in the auxiliary valve body

If no other conditions are detected, replace the TCC solenoid valve.

For vehicles repaired under warranty, use: