P07A5: Mode-one clutch-two behavior distinguishes a stuck element

P07A5 is the stuck-on diagnosis for friction element B, called C2 in this GM table. The controller seeks evidence that C2 remains coupled when mode-one operation requires a different clutch behavior. A small slip value by itself is not enough to make that judgment.

The mode-one failure conditions

The entry combines C2 slip no greater than 50rpm with its specified acceleration limit and an excess-torque condition above 320Nm. The common stuck-clutch prerequisites include an input-speed deviation from the input-speed profile greater than 200rpm. The failure decision is listed as 3.2 seconds.

These conditions distinguish P07A5 from P079B, which looks for excessive C2 slip while the clutch is commanded on. The same clutch can be involved in two different command-response questions.

Passing behavior requires release evidence

For recovery, the source lists C2 slip above 70rpm in neutral, mode one or gear one, sustained for 0.25 seconds. That is a monitor-specific indication of the expected relative motion, not a general instruction to drive through those states.

A useful event record preserves operating mode, C2 slip and torque context together. The table gives no direct proof of a seized clutch or a faulty valve and no safe forced-command procedure. Diagnosis requires the matching hybrid transmission information and professional control of propulsion and high-voltage risks before any dynamic testing.

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 162. GM PDF, page 163.