[Repair Case] 2021 Buick GL8 right electric sliding door failure

Car: Buick

Model: GL8

System: Electrical

Year: 2021

 Fault phenomenon:

The right-hand power sliding door cannot be closed electrically via the headliner or the right-hand B-pillar closing switch.

 Troubleshooting:

After receiving the customer's repair request, the following inspections were carried out according to the SBD process:

 Understand and confirm the fault description. Ask the customer about the time, place, phenomenon, and frequency of the failure. The customer just bought a new car, and when he was about to install it in the modification shop, he found that he pressed the closing button of the electric sliding door on the right side of the canopy.

 Vehicle verification. Verify the failure, press the sliding door open switch on the right side of the canopy, the electric sliding door opens normally, but when the close switch is pressed, the electric sliding door does not respond; when trying to press other electric sliding door switches, it is found that the B-pillar electric sliding door switch and the canopy condition In the same way, the electric sliding door opens normally, but cannot be closed, and the electric opening/closing through the electric sliding door handle switch is normal.

 Initial inspection. The vehicle has not been retrofitted, there is no film, and no abnormality was found after checking the fuse box and the interior parts of the car, which is indeed the same as the customer's description. The refit shop has not disassembled any parts yet, to rule out the fault caused by the installation, and start the inspection according to the normal process.

 Connect RDS, read the vehicle fault code, and find DTC: B334C-04 right electric sliding door closing switch circuit - open circuit. Check the maintenance express, maintenance announcement, maintenance communication, TAC technical briefing and TID retrieval, etc., and found no maintenance information and solutions for similar faults.

 Diagnostic Information Procedures - B334C Service Instructions. Turn the ignition switch ON and confirm that the right M14F door lock actuator does not release the power sliding door when the top and B-pillar closing switches are pressed.

 (1) Turn off the ignition switch and disconnect the M14F door lock actuator plug on the right side for 2 minutes.

(2) Measure the resistance between the ground terminal of M14F-7 and the ground of the body, and it is 0.4Ω, which is normal.

(3) Turn on the ignition switch and confirm that the parameter of the "electric sliding door latch fully open switch" of the fault diagnosis instrument is "inactive/(off)".

(4) Use a jumper wire with a 3 A fuse to bridge the M14F-6 signal circuit terminal and the M14F-7 ground circuit terminal.

(5) Confirm that the "electric sliding door latch fully open switch" parameter of the fault diagnosis instrument is still "inactive/(off)", which is abnormal.

(6) Turn off the ignition switch, remove the jumper wire, and disconnect the X2 plug of the right K58R electric sliding door control module.

(7) The ignition switch is ON, and the voltage between the K58R-10 signal circuit and the grounding iron is measured to be 0 V, which is normal.

(8) The ignition is OFF, and the end-to-end resistance of the test signal circuit K58R-10 and M14F-6 is OL—abnormal.

 At this point, the maintenance manual diagnosis process is completed. The fault conclusion is: Repair the open circuit/excessive resistance fault between the signal circuit K58R-10 to M14F-6.

The flying lead confirms the fault.

 Turn off the ignition and connect the right electric sliding door module K58R-10 to the right electric sliding door, door lock actuator M14F-6, as shown in Figure 1.

Figure 1

• Turn on the ignition, press the open/close button of the electric sliding door of the canopy and the right B-pillar respectively, and test the function of the electric sliding door. Refer to the circuit diagram and measure the open circuit fault in sections.

(1) Turn off the ignition, disconnect the X802 plug, measure the end-to-end resistance of K58R-10 and X802-10 to 0.3Ω, normal; The end-to-end resistance of X802-10 and M14F-6 is measured as OL, which is abnormal.

(2) Turn off the ignition, disconnect the X801 plug, measure the end-to-end resistance of X802-10 and X801-17, which is 0.4Ω, normal; The end-to-end resistance of X801-17 and M14F-6 measured is 0.4Ω, which is normal.

Double check the X801 connector.

(1) Check and find that the X801-17 male pin side connector terminal is shrinking. Reprocess the terminal to restore all connectors.

(2) Turn on the ignition switch, press the switch on the right electric sliding door of the canopy/B-pillar to test, the electric sliding door on the right works normally, and the fault is eliminated.

Fix bugs.

(1) Process the X801-17 male pin terminal, and measure K58R-10 and M14F-6 again. The end-to-end resistance of the signal circuit is 0.3Ω, which is normal.

(2) Restore all connectors and interior parts and initialize the window glass.

(3) The connection to the RDS detection system is normal.

(4) Operate each switch of the right electric sliding door, test that the electric sliding door opens/closes normally, and the fault is eliminated.

After the above inspection and verification, a conclusion can be drawn.

Fault point: The X801-17 terminal of the fully open signal circuit of the electric sliding door limit switch is shortened, so that when the electric sliding door is in the open position, when the top/B-pillar right sliding door closing switch is pressed, the signal circuit cannot be pulled to the If it is grounded, the right sliding door module K58R cannot receive the signal, so it cannot control the closing of the right sliding door.

Check the maintenance manual repeatedly, the door switch does not have this control logic, so the door switch can open and close the right electric sliding door normally.

Troubleshooting: Press the X801 connector harness terminal to restore all components and deliver the vehicle after all tests are normal.

Fault summary:

Based on the fault characteristics and maintenance process in the above cases, the summary is as follows:

The failure of this car has nothing to do with the modification construction, it is indeed the quality problem of the original car wiring harness connector.

Be familiar with the various components and functional principles of the electric sliding door.

Be familiar with maintenance manuals, circuit diagrams, end views, etc.