B1891–POWER LIFTGATE CONTROL CIRCUIT 2 LOW

For a complete wiring diagram Refer to Section 8W

When Monitored:
Whenever the Power Liftgate is power opening or closing.
Set Condition:
When the Power Liftgate Module senses voltage below 1.5 volts on the (Q89) Liftgate Close Driver circuit prior to starting a liftgate power cycle, this code will set.

Possible Causes

(Q89) LIFTGATE CLOSE DRIVER CIRCUIT SHORT TO GROUND

(Q89) LIFTGATE CLOSE DRIVER CIRCUIT SHORT TO (Q88) LIFTGATE OPEN DRIVER CIRCUIT

(Q88) LIFTGATE OPEN DRIVER CIRCUIT SHORT TO GROUND

POWER LIFTGATE DRIVE UNIT SHORTED

POWER LIFTGATE MODULE

1.DTC PRESENT

Does the scan tool display B1891–POWER LIFTGATE CONTROL CIRCUIT 2 LOW?

Yes

Using the wiring diagram/schematic as a guide, inspect the wiring and connectors for an intermittent condition.
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE) .

2.(Q89) LIFTGATE CLOSE DRIVER CIRCUIT SHORT TO (Q88) LIFTGATE OPEN DRIVER CIRCUIT

Is the resistance below 3.0 ohms (should be approximately 4.3 ohms)?

No

Yes

3.POWER LIFTGATE DRIVE UNIT

Is the resistance below 1000.0 ohms?

Yes

Repair the (Q89) Liftgate Close Driver circuit for a short to the (Q88) Liftgate Open Driver circuit.
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).

Replace the Power Liftgate Driver Unit in accordance with service information.
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).

4.(Q89) LIFTGATE CLOSE DRIVER CIRCUIT SHORT TO GROUND

Is the resistance below 1000.0 ohms?

Yes

Repair the (Q89) Liftgate Close Driver circuit for a short to ground.
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).

5.(Q88) LIFTGATE OPEN DRIVER CIRCUIT SHORT TO GROUND

Is the resistance above 1000.0 ohms?

Yes

Replace the Power Liftgate Module in accordance with service information.
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).

Repair the (Q88) Liftgate Open Driver circuit for a short to ground. If the (Q88) Liftgate Open Driver is OK, replace the Power Liftgate Drive Unit in accordance with the service information.
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).