Pinpoint Test A: The Power Running Board (PRB) Does Not Operate Correctly - Both Running Boards
Power Running Board (PRB)
Pinpoint Tests
Pinpoint Test A: The Power Running Board (PRB) Does Not Operate Correctly - Both Running Boards
Refer to Wiring Diagram Set 109, Power Liftgate/Retractable Running Boards for schematic and connector information. Diagrams By Number
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 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 module receives power through circuit SBB11 (BU/RD) and ground through circuit GD134 (BK/VT). The LH and RH PRB motor Hall-effect sensors receive a regulated 10-volt power supply from the PRB module through circuit CPR47 (GY/BN). The Hall-effect ground is provided by the PRB module through circuit RPR47 (BU/GN). The PRB 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 module
PINPOINT TEST A: THE POWER RUNNING BOARD (PRB) DOES NOT OPERATE CORRECTLY - BOTH RUNNING BOARDS
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A1 RETRIEVE ALL CMDTCs IN ALL MODULES
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self-Test - ALL CMDTCs.
- Are any door ajar switch or vehicle speed related DTCs present?
Yes
REFER to Multifunction Electronic Modules Multifunction Electronic Modules to diagnose the door ajar switch or vehicle speed related DTCs.
No
GO to A2.
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A2 CHECK THE OPERATION OF THE PRBs - AUTOMATIC MODE
- Set the PRB 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 should deploy when the door is open, and retract when the door is closed.
- Open and close the LH rear door. The LH PRB should deploy when the door is open, and retract when the door is closed.
- Open and close the RH front door. The RH PRB should deploy when the door is open, and retract when the door is closed.
- Open and close the RH rear door. The RH PRB should deploy when the door is open, and retract when the door is closed.
- Did both PRBs operate correctly, with no reversal of motion or noise while in motion?
Yes
The system is operating as designed. REVIEW operation of the PRB system with the customer.
No
GO to A3.
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A3 CHECK THE OPERATION OF THE PRBs - MANUAL MODE
- Set the PRB 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 deploy?
Yes
GO to A5.
No
GO to A4.
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A4 CHECK THE PRBs 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 hinge points, step area or door sill. If foreign material is found, clean the PRB 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 hinge points, step area and door sill of the LH and RH PRBs for foreign material or blockage. If any foreign material or blockage is found, remove it, and if necessary, set the PRB system to the OUT mode and clean the PRB hinge points, step area and door sill with a high-pressure washer. Avoid direct spray to the motor.
- Set the PRB 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 should deploy when the door is open, and retract when the door is closed.
- Open and close the RH front door. The RH PRB should deploy when the door is open, and retract when the door is closed.
- Does the PRB 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 hinge points, step area or door sill. REFER the customer to the Owner's Literature for correct cleaning instructions.
No
GO to A5.
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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 Interior Lighting Testing and Inspection to diagnose the interior lighting concern before attempting to diagnose the PRB concern.
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A6 CHECK THE HALL-EFFECT SENSOR POWER AND GROUND
- Disconnect: PRB LH Motor C3185.
- Disconnect: PRB RH Motor C3186.
- Ignition ON.
- Measure the voltage between RH PRB 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.
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A7 CHECK HALL-EFFECT SENSOR POWER CIRCUIT FOR VOLTAGE
- Measure the voltage between RH PRB 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.
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A8 CHECK HALL-EFFECT SENSOR POWER CIRCUIT FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Disconnect: PRB Module C3313B.
- Measure the resistance between RH PRB motor C3186-4, circuit CPR47 (GY/BN), harness side and PRB module C3313B-5, circuit CPR47 (GY/BN), harness side; and between RH PRB motor C3186-4, circuit CPR47 (GY/BN), harness side and ground.
- Is the resistance less than 5 ohms between the PRB motor and PRB module; and greater than 10,000 ohms between the PRB motor and ground?
Yes
GO to A9.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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A9 CHECK THE PRB MODULE POWER CIRCUIT FOR VOLTAGE
- Measure the voltage between PRB 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. REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. Diagrams By Number
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A10 CHECK THE PRB MODULE GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure the resistance between the PRB 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.
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A11 CHECK THE HALL-EFFECT SENSOR GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: PRB Module C3313B.
- Measure the resistance between RH PRB motor C3186-6, circuit RPR47 (BU/GN), harness side and PRB 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.
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A12 CHECK THE HALL-EFFECT SENSOR POWER CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: PRB Module C3313B.
- Ignition ON.
- Measure the voltage between RH PRB 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.
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A13 CHECK THE PRB MODULE FOR CORRECT OPERATION
- Connect: PRB LH Motor C3185.
- Connect: PRB RH Motor C3186.
- Visually inspect all PRB module connectors.
- Check for:
- corrosion.
- pushed-out pins.
- Connect all PRB 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 module. REFER to Power Running Board (PRB) Module Service and Repair. 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.
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