Some owners of 2010 Cadillac SRX vehicles may complain about an inoperative power liftgate. During diagnosis, you may find DTC B153A set in the power liftgate control module.
1. Disconnect the connector at the liftgate latch assembly. With the liftgate latch connector disconnected, the three signals for the ratchet, pawl and the sector should be inactive on the scan tool.
2. Install a 3A fused jumper wire between each signal circuit terminal and the ground circuit terminal 2. Monitor the scan tool as each individual circuit is jumpered to ground. The scan tool should read “active.”
3. If either test fails, check the wiring for the signal circuits, low reference circuit, or try a power liftgate control module from a known good vehicle.
4. If both tests pass, monitor the internal switch inputs in the liftgate assembly for proper operation.
With the liftgate in the open position, the ratchet and pawl should read “active” and the sector should read “inactive.” With the liftgate in the secondary latched position, the pawl should read “inactive” and the ratchet and sector should read “active.” With the liftgate fully closed, the pawl, ratchet and sector should all read “inactive.”
5. If one of the internal liftgate latch assembly switch inputs is not reading correctly in one of the positions, and the vehicle passes test 1 and 2 above, replace the liftgate latch assembly.
