B153A liftgate not working

Diagnose and fix B153A liftgate not working

If you own an Enclave, CTS, STX, Avalanche, Acadia, Yukon, Tahoe, Suburban or Outlook with power liftgate and experience a trouble code B153A liftgate not working, here’s the diagnostic procedure, a GM service bulletin #PIT4041D and fix for the vehicles listed below.

B153A 00:  Liftgate Latch Switch Signal Circuit— When the liftgate control module detects an open/high resistance in the ratchet, pawl, and/or the sector signal circuit, an open/high resistance in the liftgate latch low reference circuit, or any incorrect combination of signals from the following switch inputs:

B153A 08:  Liftgate Latch Switch Signal Circuit Signal Invalid —When the liftgate control module detects a loss of B+ voltage, an open/high resistance in the sensor signal circuit, an open/high resistance in the liftgate latch low reference circuit, or any incorrect combination of signals from the following switch inputs

How the power liftgate works

The liftgate latch contains a ratchet, pawl, and sector switches. They communicate with the the liftgate control module to determine the state of the latch during cinching or unlatching. The ratchet and pawl switches will show as inactive when the primary and secondary latches are latched, and the sector switch will show as active during the cinch operation.

The latch switch signal circuits are supplied power through a resistor and monitored within the liftgate control module. The latch switches share a common low reference circuit from the liftgate control module and when the switch contacts close the signal circuit goes low and the liftgate control module determines the switch to be active.

Diagnose and fix B153A liftgate not working

1. Disconnect the electrical connector to the lift gate latch. The 3 signals for the ratchet, pawl, and the sector should be now show as inactive on a scan tool.

2. Connect a jumper wire between each signal circuit terminal (for the pawl, sector, and ratchet) and the ground circuit terminal 2 and monitor the reading on your scan tool as each individual circuit is jumped to ground, the scan tool should read “active”.

3. If any of the connection test above fails, check the wiring for the signal circuits, low reference circuit, or try a power lift gate control module from a known good vehicle.

4. If both of the above tests pass, monitor the internal switch inputs in the lift gate latch assembly for proper operation.

Liftgate latch connector wiring diagram and pinout

1 0.5 L-BU Ground
2 Not Used
3 0.5 BK Ground
4 0.5 L-GN Rear Access Open Switch Signal
5 0.35 BK Ground
6 0.5 PK/BK Liftgate Ajar Switch Signal

Liftgate cinch connector

1 2 BN Liftgate Cinch Latch Motor Open Control
2 0.35 PU/WH Low Reference
3 2 L-BU Liftgate Cinch Latch Motor Close Control
4 0.35 D-GN Latch Sector Switch Signal
5 0.35 GY Latch Pawl Switch Signal
6 0.35 PK/BK Latch Ratchet Switch Signalal

Vehicles affected by GM service bulletin #PIT4041D

2008 – 2013 Buick Enclave
2010 – 2013 Cadillac CTS Wagon
2007 – 2013 Cadillac SRX
2007 – 2013 Cadillac Escalade, Escalade ESV
2007 – 2013 Chevrolet Avalanche, Tahoe, Suburban
2009 – 2013 Chevrolet Traverse
2007 – 2013 GMC Yukon Models
2007 – 2013 GMC Acadia
2007 – 2010 Saturn OUTLOOK
with Power Lift Gate (RPO E61 or TB5)

Most common fixes for B153A liftgate not working

Wiring harness issues to the latch and cinch connectors,
Worn hydraulic struts
Faulty latch

©, 2020 Rick Muscoplat