B1972

B1972 - POWER LIFTGATE LATCH RELEASE - RATCHET PRIMARY SWITCH PERFORMANCE

B1972 - Power Liftgate Latch Release - Ratchet Primary Switch Performance:

WHEN MONITORED
Whenever the power liftgate in performing a opening operation.

SET CONDITION
The pawl switch was detected as grounded but the ratchet switch remained open.

POSSIBLE CAUSES
- Binding liftgate
- (Q901) Logic ground circuit open
- (G78) Liftgate ajar switch sense wire open
- Power liftgate latch
- Power liftgate module

Diagnostic Test

1. DTC PRESENT

NOTE: This DTC will only set during the releasing operation after the four second time out. This may make it difficult to reproduce.

With the scan tool, record and erase DTC's.
Turn the ignition off, wait 10 seconds, then turn the ignition on.
Operate the power liftgate several times if possible.
With the scan tool, read ACTIVE DTCs.

Q: Does the scan tool display B1972-POWER LIFTGATE LATCH RELEASE - RATCHET PRIMARY SWITCH PERFORMANCE?

YES: Go To 2

NO: Using the wiring diagram/schematic as a guide, inspect the wiring and connectors for an intermittent condition. Operate the door several times and check for any binding or other obstructions. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

2. BINDING LIFTGATE

Examine the liftgate for proper fit and alignment, loose/hard or torn seals, misaligned latch striker or anything that would cause an obstruction to proper operation.

Manually operate the liftgate of a known good vehicle and notice the effort needed to open and close. Compare the effort needed on the disabled liftgate.

Especially notice the effort needed to unlatch and close the liftgate.

Q: Does it take more effort to operate the liftgate than it should?

YES: Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 3

3. POWER LIFTGATE MODULE

With the scan tool, monitor the PRIMARY RATCHET SWITCH.
Using a screwdriver, click the latch to the second detent while observing the scan tool.
Unlatch the latch by pressing the handle switch and observe the scan tool for a change of state.
Repeat this step several times while moving the liftgate in different positions and wiggling the harness to check for an intermittent open or shorted circuit.

Q: Did the scan tool show the switch state changing correctly every time?

NO: Go To 4
YES: Replace the Power Liftgate Module. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

4. (Q901) LOGIC GROUND WIRE OPEN




Turn the ignition off.
Turn all lights off.
Disconnect the Power Liftgate Latch connector.
Measure the resistance between ground and the (Q901) Logic Ground circuit in the Liftgate Latch connector.
Wiggle the harness while observing the ohmmeter.

Q: Is the resistance below 9.5 ohms?

YES: Go To 5
NO: Repair the (Q901) Logic Ground wire for an open. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

5. (G78) LIFTGATE AJAR SWITCH SENSE WIRE OPEN




Disconnect the Power Liftgate C2 connector.
Measure the resistance of the (G78) Liftgate Ajar Switch Sense wire between the PLG C2 connector and the Liftgate Latch connector. Wiggle the harness while observing the ohmmeter.

Q: Is the resistance below 2.0 ohms?

YES: Replace the Power Liftgate Latch. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Repair the (G78) Liftgate Ajar Switch Sense wire for an open. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test