Pinpoint Test AJ: All-Wheel Drive (AWD) System Functional Test
Four Wheel Drive (4WD) Systems - 1-Speed Torque-On-Demand
Pinpoint Tests
Pinpoint Test AJ: All-Wheel Drive (AWD) System Functional Test
Refer to Wiring Diagram Set 34, Four-Wheel Drive System for schematic and connector information. Diagrams By Number
Normal Operation
When the All-Wheel Drive (AWD) system is in AWD mode, all 4 wheels rotate at the same speed. The amount of traction the vehicle can achieve depends on the amount of traction each tire can establish with the road surface. In order for the AWD system to operate correctly, each wheel/tire assembly must have matching sizes, and the front and rear axle ratios must match.
This pinpoint test is intended to diagnose the following:
- AWD system and/or related components
PINPOINT TEST AJ: ALL-WHEEL DRIVE (AWD) SYSTEM FUNCTIONAL TEST
NOTE: 4H (4X4) is not intended for driving on hard/dry surfaces; using 4H mode while driving on these surfaces may produce noises like intermittent clunking, but will not damage driveline components.
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AJ1 CHECK 4X4 AUTO MODE OPERATION
- Ignition ON.
- Shift the transmission in the NEUTRAL position.
- Switch the Mode Select Switch (MSS), to AWD (AUTO) mode.
- Do the 4WD indicators turn off?
Yes
GO to AJ4.
No
GO to AJ2.
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AJ2 CHECK FOR DTCs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - TCCM.
- Are DTCs present?
Yes
REFER to the Transfer Case Control Module (TCCM) DTC Chart for diagnosis. Four Wheel Drive (4WD) Systems - 1-Speed Torque-On-Demand
No
GO to AJ3.
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AJ3 CHECK FOR WIND-UP IN 2H (4X2) MODE
- Drive the vehicle on a dry, hard surface in turns.
- Is wind-up present in turns?
Yes
GO to Pinpoint Test AE. Pinpoint Test AE: The Vehicle Does Not Shift Between AWD (4X4 AUTO) and 4H (4X4) Modes Correctly
No
GO to Pinpoint Test AF. Pinpoint Test AF: Four-Wheel Drive (4WD) Does Not Engage at Speed Correctly
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AJ4 CHECK 4X4 AUTO MODE OPERATION
- Select 4X4 AUTO mode.
- Does the 4X4 AUTO indicator illuminate correctly?
Yes
GO to AJ7.
No
GO to AJ5.
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AJ5 CHECK FOR DTCs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - TCCM.
- Are DTCs present?
Yes
REFER to the Transfer Case Control Module (TCCM) DTC Chart for diagnosis. Four Wheel Drive (4WD) Systems - 1-Speed Torque-On-Demand
No
GO to AJ6.
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AJ6 CHECK FOR WIND-UP IN 4X4 AUTO MODE
- Drive the vehicle on a dry, hard surface, executing turns while applying the throttle.
- Is wind-up present?
Yes
GO to AJ7.
No
GO to AJ8.
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AJ7 CHECK THE 4WD PWM CLUTCH STATUS (4WD_CLTCH_OUT) PID
- Enter the following diagnostic mode on the scan tool: DataLogger - TCCM.
- Monitor the 4WD_CLTCH_OUT PID.
- Does the 4WD_CLTCH_OUT PID indicate 2 to 10% clutch application at closed throttle?
Yes
GO to AJ8.
No
GO to AJ9.
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AJ8 CHECK FOR WIND-UP IN 4WD AUTO MODE WITH 100% CLUTCH USING THE 4WD PWM CLUTCH STATUS (4WD_CLTCH_OUT) ACTIVE COMMAND
- Enter the following diagnostic mode on the scan tool: DataLogger - TCCM.
- Command the 4WD_CLTCH_OUT to 100%.
- Drive the vehicle on a dry, hard surface, executing turns.
- Is wind-up present?
Yes
GO to AJ9.
No
CHECK the transfer case. TEST the system for normal operation.
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AJ9 CHECK AVERAGE FRONT WHEEL SPEED (FRT_WHL_SPD) AND AVERAGE REAR WHEEL SPEED (REAR_WHL_SPD) PIDs
- Enter the following diagnostic mode on the scan tool: DataLogger - TCCM.
- Monitor the FRT_WHL_SPD and REAR_WHL_SPD PIDs.
- Drive the vehicle 30 km/h (18 mph).
- Record and compare the FRT_WHL_SPD and REAR_WHL_SPD PIDs.
- Do the FRT_WHL_SPD and REAR_WHL_SPD PID values match within 1.5 km/h (1 mph)?
Yes
GO to AJ10.
No
VERIFY all 4 tires are the same size and brand. INSTALL new tires as necessary. If the tires are OK, CHECK the ABS. REFER to Vehicle Dynamic Systems Testing and Inspection and VERIFY that the 4 road tire sizes match. TEST the system for normal operation.
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AJ10 CHECK THE ABSOLUTE THROTTLE POSITION (TP_TCCM) PID
- Enter the following diagnostic mode on the scan tool: DataLogger - TCCM.
- Ignition ON.
- Monitor the TP_TCCM PID.
- NOTE: The TP_TCCM PID is Accelerator Pedal Position (APP) as communicated by the PCM via High Speed Controller Area Network (HS-CAN).
- Slowly move throttle from closed throttle to Wide Open Throttle (WOT) and observe the TP_TCCM PID.
- Does the TP_TCCM PID value vary between 0 at closed throttle and 255 at WOT?
Yes
GO to AJ11.
No
CHECK the APP sensor and/or PCM. REFER to Computers and Control Systems. CHECK the HS-CAN, REFER to Module Communications Network Testing and Inspection. TEST the system for normal operation.
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AJ11 CHECK 4X4 MODE OPERATION
- Switch the MSS to 4H mode.
- Does the 4X4 mode indicator illuminate correctly?
Yes
GO to AJ14.
No
GO to AJ12.
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AJ12 CHECK FOR DTCs
- Shift the transmission into the PARK position.
- Enter the following diagnostic mode on the scan tool: Self Test - TCCM.
- Are DTCs retrieved?
Yes
REFER to the Transfer Case Control Module (TCCM) DTC Chart for diagnosis. Four Wheel Drive (4WD) Systems - 1-Speed Torque-On-Demand
No
GO to AJ13.
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AJ13 CHECK FOR WIND-UP IN 4X4 MODE
- Drive the vehicle on a dry, hard surface while executing turns.
- Is wind-up present in turns?
Yes
GO to Pinpoint Test AF. Pinpoint Test AF: Four-Wheel Drive (4WD) Does Not Engage at Speed Correctly
No
GO to Pinpoint Test AE. Pinpoint Test AE: The Vehicle Does Not Shift Between AWD (4X4 AUTO) and 4H (4X4) Modes Correctly
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AJ14 CHECK FOR STRAIGHTLINE WIND-UP IN 4X4 MODE
- Drive the vehicle on a dry, hard surface.
- Is straightline wind-up present?
Yes
GO to Pinpoint Test AH. Pinpoint Test AH: Straightline Driveline Wind-up
No
GO to AJ15.
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AJ15 CHECK FOR 4X4 MODE WIND-UP IN TURNS
- Drive the vehicle on a dry, hard surface while executing turns.
- Is wind-up present in turns?
Yes
GO to AJ16.
No
GO to Pinpoint Test AE. Pinpoint Test AE: The Vehicle Does Not Shift Between AWD (4X4 AUTO) and 4H (4X4) Modes Correctly
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AJ16 CHECK 4X4 MODE TO 4X2 MODE SHIFT
- With the vehicle at rest, brake applied and transmission in NEUTRAL, switch the MSS from 4X4 mode to 4X2 mode.
- Do the 4WD indicators turn off?
Yes
GO to AJ19.
No
GO to AJ17.
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AJ17 CHECK FOR DTCs
- Shift the transmission into the PARK position.
- Enter the following diagnostic mode on the scan tool: Self Test - TCCM.
- Are DTCs retrieved?
Yes
REFER to the Transfer Case Control Module (TCCM) DTC Chart for diagnosis. Four Wheel Drive (4WD) Systems - 1-Speed Torque-On-Demand
No
GO to AJ18.
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AJ18 CHECK FOR WIND-UP IN 4X2 MODE
- Drive the vehicle on a dry, hard surface while executing turns.
- Is wind-up present in turns?
Yes
GO to Pinpoint Test AE. Pinpoint Test AE: The Vehicle Does Not Shift Between AWD (4X4 AUTO) and 4H (4X4) Modes Correctly
No
GO to Pinpoint Test AF. Pinpoint Test AF: Four-Wheel Drive (4WD) Does Not Engage at Speed Correctly
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AJ19 CHECK FOR TRANSFER CASE DISENGAGEMENT
- With the vehicle in NEUTRAL, position it on a hoist. Refer to Jacking and Lifting Service and Repair.
- Rotate the rear driveshaft while observing the front driveshaft.
- Does the front driveshaft rotate?
Yes
CHECK the transfer case. TEST the system for normal operation.
No
GO to AJ20.
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AJ20 CHECK FOR LH AND RH IWE DISENGAGEMENT
- NOTE: The engine must be at idle during the following steps.
- Start the engine and allow it to idle.
- Rotate the LF tire one revolution forward and one revolution backward while observing the LF halfshaft and U-joint.
- Rotate the RF tire one revolution forward and one revolution backward while observing the RF halfshaft and U-joint.
- Did either front axle shaft and U-joint rotate?
Yes
GO to Pinpoint Test AD. Pinpoint Test AD: The Front Axle Does Not Engage/Disengage Correctly
No
GO to AJ21.
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AJ21 CHECK FOR IWE VACUUM LEAKS
- Ignition OFF.
- Disconnect both vacuum lines from the Integrated Wheel End (IWE) solenoid.
- Using a hand vacuum pump, apply 508 mm (20 in) Hg of vacuum to the IWE apply vacuum circuit.
- Observe the vacuum reading.
- Did the vacuum drop more than 25 mm (1 in) Hg per minute?
Yes
CHECK the IWE and related components for leaks. GO to Pinpoint Test AD. Pinpoint Test AD: The Front Axle Does Not Engage/Disengage Correctly
No
GO to AJ22.
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AJ22 CHECK 4X2 MODE TO 4X4 MODE SHIFT AT SPEED ABOVE 32 KM/H (20 MPH)
- Switch the MSS to 4X2 mode.
- Drive the vehicle on the road and switch the MSS from 4X2 mode to 4X4 mode while driving above 32 km/h (20 mph).
- Does the transfer case shift to 4X4 mode satisfactorily?
Yes
The 4WD system is functioning correctly.
No
GO to Pinpoint Test AF. Pinpoint Test AF: Four-Wheel Drive (4WD) Does Not Engage at Speed Correctly
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