Pinpoint Test A: The Power Running Board (PRB) Does Not Operate Correctly - Both Running Boards

Power Running Board (PRB)

Pinpoint Test A: The Power Running Board (PRB) Does Not Operate Correctly - Both Running Boards

NOTE: The Power Running Board (PRB) module will stop functionality when battery voltage drops below 9.5 volts (early build) or 9.0 volts (late build). The PRB (Power Running Board) system will recover at the next door ajar transition provided that the battery voltage remains above 9.0 volts (late build only).

Normal Operation

The PRB (Power Running Board) module receives power through circuit SBB11 (BU/RD) and ground through circuit GD134 (BK/VT). The LH and RH PRB (Power Running Board) motor Hall-effect sensors receive a regulated 10-volt power supply from the PRB (Power Running Board) module through circuit CPR47 (GY/BN). The Hall-effect ground is provided by the PRB (Power Running Board) module through circuit RPR47 (BU/GN). The PRB (Power Running Board) module receives door ajar and vehicle speed status over the Controller Area Network (CAN).

This pinpoint test is intended to diagnose the following:

- Fuse

- Wiring, terminals or connectors

- PCM

- Instrument Cluster (IC)

- PRB (Power Running Board) module

PINPOINT TEST A : THE Power Running Board (PRB) DOES NOT OPERATE CORRECTLY - BOTH RUNNING BOARDS

A1 RETRIEVE ALL CMDTCs (Continuous Memory Diagnostic Trouble Codes) IN ALL MODULES

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: Self-Test- ALL CMDTCs (Continuous Memory Diagnostic Trouble Codes).

Are any door ajar switch or vehicle speed related DTCs present?

Yes
REFER to Body Control Systems to diagnose the door ajar switch or vehicle speed related DTCs.
No
GO to A2.

A2 CHECK THE OPERATION OF THE PRBs (Power Running Boards) - AUTOMATIC MODE

- Set the PRB (Power Running Board) system to the AUTO (enabled) mode, where the boards automatically deploy when a door on the same side is opened, and retract when the door is closed.

- Open and close the LH front door. The LH PRB (Power Running Board) should deploy when the door is open, and retract when the door is closed.

- Open and close the LH rear door. The LH PRB (Power Running Board) should deploy when the door is open, and retract when the door is closed.

- Open and close the RH front door. The RH PRB (Power Running Board) should deploy when the door is open, and retract when the door is closed.

- Open and close the RH rear door. The RH PRB (Power Running Board) should deploy when the door is open, and retract when the door is closed.

Did both PRBs (Power Running Boards) operate correctly, with no reversal of motion or noise while in motion?

Yes
The system is operating as designed. REVIEW operation of the PRB (Power Running Board) system with the customer.
No
GO to A3.

A3 CHECK THE OPERATION OF THE PRBs (Power Running Boards) - MANUAL MODE

- Set the PRB (Power Running Board) system to the OUT mode, where the boards are deployed all the time, regardless of door open/closed status and vehicle speed is less than 8 km/h (5 mph).

Did both PRBs (Power Running Boards) deploy?

Yes
GO to A5.
No
GO to A4.

A4 CHECK THE PRBs (Power Running Boards) FOR FOREIGN MATERIAL

- NOTE: If the system has false bounce-back, stops in mid-travel, is noisy or will not deploy or stow completely, check to see if any foreign material is caught in the PRB (Power Running Board) hinge points, step area or door sill. If foreign material is found, clean the PRB (Power Running Board) hinge points, step area and door sill with a high-pressure washer. If the system operates correctly after cleaning, refer the customer to the Owner's Literature for correct cleaning instructions.

Check the PRB (Power Running Board) hinge points, step area and door sill of the LH and RH PRBs (Power Running Boards) for foreign material or blockage. If any foreign material or blockage is found, remove it, and if necessary, set the PRB (Power Running Board) system to the OUT mode and clean the PRB (Power Running Board) hinge points, step area and door sill with a high-pressure washer. Avoid direct spray to the motor.

- Set the PRB (Power Running Board) system to the AUTO (enabled) mode, where the boards automatically deploy when a door on the same side is opened, and retract when the door is closed.

- Open and close the LH front door. The LH PRB (Power Running Board) should deploy when the door is open, and retract when the door is closed.

- Open and close the RH front door. The RH PRB (Power Running Board) should deploy when the door is open, and retract when the door is closed.

Does the PRB (Power Running Board) system operate normally during all test steps?

Yes
The system is operating normally. The concern may have been caused by foreign material or blockage in the PRB (Power Running Board) hinge points, step area or door sill. REFER the customer to the Owner's Literature for correct cleaning instructions.
No
GO to A5.

A5 VERIFY THE DOOR AJAR SWITCH OPERATION

- Open and close each door, verify the interior lights operate correctly and door ajar is noted on the vehicle message center.

Do the interior lights turn ON when the door is opened and OFF when the door is closed?

Yes
GO to A6.
No
REFER to Lighting and Horns to diagnose the interior lighting concern before attempting to diagnose the PRB (Power Running Board) concern.

A6 CHECK THE HALL-EFFECT SENSOR POWER AND GROUND

- Disconnect: PRB (Power Running Board) LH Motor C3185.

- Disconnect: PRB (Power Running Board) RH Motor C3186.

- Ignition ON.

- Measure the voltage between RH PRB (Power Running Board) motor C3186-4, circuit CPR47 (GY/BN), harness side and C3186-6, circuit RPR47 (BU/GN), harness side.






- Open RH door.

- Voltage signal will only be present for less than one second.

Is the voltage between 7 and 10.5 volts?

Yes
GO to A13.
No
If the voltage was less than 7 volts, GO to A7.

If the voltage was greater than 10.5 volts, GO to A12.

A7 CHECK HALL-EFFECT SENSOR POWER CIRCUIT FOR VOLTAGE

- Measure the voltage between RH PRB (Power Running Board) motor C3186-4, circuit CPR47 (GY/BN), harness side and ground.






- Open RH door.

- Voltage signal will only be present for less than one second.

Is the voltage between 7 and 10.5 volts?

Yes
GO to A11.
No
GO to A8.

A8 CHECK HALL-EFFECT SENSOR POWER CIRCUIT FOR AN OPEN OR SHORT TO GROUND

- Ignition OFF.

- Disconnect: PRB (Power Running Board) Module C3313B.

- Measure the resistance between RH PRB (Power Running Board) motor C3186-4, circuit CPR47 (GY/BN), harness side and PRB (Power Running Board) module C3313B-5, circuit CPR47 (GY/BN), harness side; and between RH PRB (Power Running Board) motor C3186-4, circuit CPR47 (GY/BN), harness side and ground.






Is the resistance less than 5 ohms between the PRB (Power Running Board) motor and PRB (Power Running Board) module; and greater than 10,000 ohms between the PRB (Power Running Board) motor and ground?

Yes
GO to A9.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

A9 CHECK THE PRB (Power Running Board) MODULE POWER CIRCUIT FOR VOLTAGE

- Measure the voltage between PRB (Power Running Board) module C3313B-1, circuit SBB11 (BU/RD), harness side and ground.






Is battery voltage present?

Yes
GO to A10.
No
VERIFY Battery Junction Box (BJB) fuse 11 (30A) is OK. If OK, REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short [1][2]Diagrams By Number. REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

A10 CHECK THE PRB (Power Running Board) MODULE GROUND CIRCUIT FOR AN OPEN

- Ignition OFF.

- Measure the resistance between the PRB (Power Running Board) module C3313B-4, circuit GD139 (BK/YE), harness side and ground.






Is the resistance less than 5 ohms?

Yes
GO to A13.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

A11 CHECK THE HALL-EFFECT SENSOR GROUND CIRCUIT FOR AN OPEN

- Ignition OFF.

- Disconnect: PRB (Power Running Board) Module C3313B.

- Measure the resistance between RH PRB (Power Running Board) motor C3186-6, circuit RPR47 (BU/GN), harness side and PRB (Power Running Board) module C3313B-14, circuit RPR47 (BU/GN), harness side.






Is the resistance less than 5 ohms?

Yes
GO to A13.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

A12 CHECK THE HALL-EFFECT SENSOR POWER CIRCUIT FOR A SHORT TO VOLTAGE

- Ignition OFF.

- Disconnect: PRB (Power Running Board) Module C3313B.

- Ignition ON.

- Measure the voltage between RH PRB (Power Running Board) motor C3186-4, circuit CPR47 (GY/BN), harness side and ground.






Is any voltage present?

Yes
REPAIR the circuit. CLEAR The DTCs. REPEAT the self-test.
No
GO to A13.

A13 CHECK THE PRB (Power Running Board) MODULE FOR CORRECT OPERATION

- Connect: PRB (Power Running Board) LH Motor C3185.

- Connect: PRB (Power Running Board) RH Motor C3186.

- Visually inspect all PRB (Power Running Board) module connectors.

- Check for:
- corrosion.

- pushed-out pins.


- Connect all PRB (Power Running Board) module connectors and make sure they seat correctly.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new PRB (Power Running Board) module. REFER to Power Running Board (PRB) Module . CLEAR the DTCs. REPEAT the self-test.
No
The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.