P079B: Clutch two has a one-second loaded-slip criterion

In GM's cited hybrid transmission, P079B monitors excessive slip of clutch two while C2 is commanded on. The controller combines the slip measurement with pressure command, estimated torque and fill detection. Reading the slip channel alone leaves those important conditions unknown.

The C2 threshold is not the C1 timer

Failure is listed as C2 slip above 200rpm for one second, with pressure command at least 1800kPa and torque estimate at least 200Nm. Clutch fill must have been detected. The neighboring C1 entry allows a three-second failure interval, making code-specific timing important even though their speed thresholds match.

C2's pass condition requires slip below 50rpm for 0.125 seconds. The pressure command remains part of the condition, while the pass torque requirement is reduced to 20Nm.

Interpret command and response separately

Save the requested pressure and actual slip response on the same timeline. The word “command” matters: this source does not claim a hydraulic pressure sensor verified that 1800kPa was physically delivered. A command-response failure can support further hydraulic or mechanical investigation without choosing the failed component by itself.

The table supplies no universal friction-material diagnosis, solenoid replacement or fluid specification. Use the correct hybrid-transmission procedure to establish those details. Controlled professional testing is required around a system capable of applying propulsion torque; do not reproduce the threshold by improvising a loaded clutch test.

Source and applicability

GM 2010 10OBDG10 Hybrid Diagnostics, only the cited controller and monitor. These are historical calibration examples; individual vehicle, engine and hardware applicability is not established. GM PDF, page 197.