DTC B1589 or B158A - Liftgate Angle Sensor Malfunction
Diagnostic Instructions Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions DTC Descriptor DTC B1589 Rear Closure Position Sensor Signal 1 DTC B158A Rear Closure Position Sensor Signal 2 Symptom Byte Information: Symptom Byte List Diagnostic Fault Information
| Circuit number | Circuit Function | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performan |
|---|---|---|---|---|---|
| 4683 | Voltage Reference | 1 | 1 | 1 | — |
| 4685 | Signal | B1589 29 | B1589 29 | — | B1589 29 |
| 4686 | Signal | B158A 29 | B158A 29 | — | B158A 29 |
| 4687 | Low Reference | — | B158A 29, B1589 29 | — | — |
| 1. Power liftgate function erratic |
Circuit/System Description The K194 Rear Gate Module continuously monitors power liftgate operation and calculates its location and direction of travel using 2 Hall effect sensors that are part of the M31L Liftgate Power Assist Actuator - Left. The Hall effect sensors are 12 V 2-wire sensors and are supplied with a 12 V power, ground and signal circuits from the K194 Rear Gate Module. The Hall effect sensor signal circuits are referenced from voltage within the K194 Rear Gate Module and pulsed low by the Hall effect sensors. Conditions for Running the DTC Power Liftgate (TB5) » Commanded Conditions for Setting the DTC B1589 29 Circuit 4685 is shorted to ground or has an open/high resistance B1589 29, B158A 29 Circuit 4687 has an open/high resistance B158A 29 Circuit 4686 is shorted to ground or has an open/high resistance Actions Taken When the DTC Sets Liftgate power open and close function operation erratic Conditions for Clearing the DTC A current DTC will clear when the diagnostic runs and passes. A history DTC will clear after 40 consecutive malfunction-free ignition cycles. Diagnostic Aids If the liftgate will not release from the closed position, refer to Opening the Liftgate Without Electrical Power for the appropriate procedure Whenever the rear gate module loses power or is disconnected, the ignition must be cycled OFF then ON in order to reactivate the rear gate module. Reference Information Schematic Reference Liftgate Schematics Connector End View Reference Master Electrical Component List Description and Operation Liftgate Description and Operation Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Scan Tool Reference Control Module References for scan tool information Circuit/System Verification
- Ignition » On / Vehicle » In Service Mode
- Operate the component: Liftgate » Open Verify the scan tool parameter: Rear Gate Travel = Greater than 70% ⇒ If not in the specified range or does not change Refer to: Circuit/System Testing ⇓ If in the specified range and changes
- Operate the component: Liftgate » Close Verify the scan tool parameter: Rear Gate Travel = Less than 5% ⇒ If greater than the specified range Refer to: Circuit/System Testing ⇓ If less than the specified range
- A fault that is not currently present may have been caused by a intermittent condition. Circuit/System Testing
- Ignition OFF, disconnect the X3 harness connector at the K194 Rear Gate Module.
- Test for infinite resistance between each circuit terminal listed below and ground: Voltage reference circuit terminal 4 X3 Signal circuit terminal 3 X3 Signal circuit terminal 7 X3 Low reference circuit terminal 6 X3 ⇒ If less than infinite resistance Replace the M31L Liftgate Power Assist Actuator - Left ⇓ If infinite resistance
- Ignition ON
- Test for less than 1 V between circuit terminal listed below and ground: Voltage reference circuit terminal 4 X3 Signal circuit terminal 3 X3 Signal circuit terminal 7 X3 Low reference circuit terminal 6 X3 ⇒ If 1 V or greater Replace the M31L Liftgate Power Assist Actuator - Left ⇓ If less than 1 V
- Connect a 3A fused jumper wire between the voltage reference circuit terminal 4 and B+.
- Connect a 3A fused jumper wire between the low reference circuit terminal 6 and ground.
- Connect a DMM between the signal circuit terminal 3 and ground.
- Verify the voltage varies while manually opening and closing the liftgate. ⇒ If the voltage does not vary Replace the M31L Liftgate Power Assist Actuator - Left ⇓ If the voltage varies
- Connect a DMM between the signal circuit terminal 7 and ground.
- Verify the voltage varies while manually opening and closing the liftgate. ⇒ If the voltage does not vary Replace the M31L Liftgate Power Assist Actuator - Left ⇓ If the voltage varies
- Replace the K194 Rear Gate Module Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Liftgate Power Assist Actuator Replacement For control module replacement, programming, and setup refer to: Control Module References