Pinpoint Test I: Four-Wheel Drive (4WD) System Functional Test
Four Wheel Drive (4WD) Systems - 1-Speed Torque-On-Demand
Pinpoint Test I:Four-Wheel Drive (4WD) System Functional Test
Refer to Wiring Diagram Set 34, Four-Wheel Drive System for schematic and connector information Electrical Diagrams.
Normal Operation
When the Four-Wheel Drive (4WD) system is in 4WD (Four-Wheel Drive) 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 4WD (Four-Wheel Drive) 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:
- 4WD (Four-Wheel Drive) indicator
- Transfer Case Control Module (TCCM)
- Transfer case and related components
- Wheel/tire assemblies
PINPOINT TEST I : Four-Wheel Drive (4WD) 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.
I1 CHECK 4X4 AUTO MODE OPERATION
- Ignition ON.
- Shift the transmission in the NEUTRAL position.
- Switch the Mode Select Switch (MSS), to AWD (AUTO) mode.
Are there any 4WD (Four-Wheel Drive) mode indicators present in the Instrument Cluster (IC) message center?
Yes
GO to I2.
No
GO to I4.
I2 CHECK FOR TCCM (Transfer Case Control Module) DTCs
- Shift the transmission into the PARK position.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self-Test- TCCM (Transfer Case Control Module).
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 I3.
I3 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 D. Pinpoint Test D: The Vehicle Does Not Shift Between 4X4 AUTO and 4X4 Modes Correctly
No
GO to Pinpoint Test E. Pinpoint Test E: Four-Wheel Drive (4WD) Does Not Engage At Speed Correctly
I4 CHECK 4X4 AUTO MODE OPERATION
- Select 4X4 AUTO mode.
Does the 4X4 AUTO indicator illuminate correctly?
Yes
GO to I7.
No
GO to I5.
I5 CHECK FOR DTCs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self-Test- TCCM (Transfer Case Control Module).
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 I6.
I6 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 in turns?
Yes
GO to I7.
No
GO to I8.
I7 CHECK THE 4WD (Four-Wheel Drive) PWM (Pulse-Width Modulation) CLUTCH STATUS (4WD_CLTCH_OUT) PID
- Enter the following diagnostic mode on the scan tool: DataLogger- TCCM (Transfer Case Control Module).
- Monitor the 4WD_CLTCH_OUT PID.
Does the PID indicate 2 to 10% clutch application at closed throttle?
Yes
GO to I8.
No
GO to I9.
I8 CHECK FOR WIND-UP IN 4WD (Four-Wheel Drive) AUTO MODE WITH 100% CLUTCH USING THE 4WD (Four-Wheel Drive) PWM (Pulse-Width Modulation) CLUTCH STATUS (4WD_CLTCH_OUT) ACTIVE COMMAND
- Enter the following diagnostic mode on the scan tool: DataLogger- TCCM (Transfer Case Control Module).
- Command the 4WD_CLTCH_OUT to 100%.
- Drive the vehicle on a dry, hard surface, executing turns.
Is wind-up present in turns?
Yes
GO to I9.
No
CHECK the transfer case. TEST the system for normal operation.
I9 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 (Transfer Case Control Module).
- 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 I10.
No
VERIFY all 4 tires are the same size and brand. INSTALL new tires as necessary. If the tires are OK, CHECK the ABS and VERIFY that the 4 road tire sizes match. TEST the system for normal operation.
I10 CHECK THE ABSOLUTE THROTTLE POSITION (TP_TCCM) PID
- Enter the following diagnostic mode on the scan tool: DataLogger- TCCM (Transfer Case Control Module).
- 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 100% at WOT (Wide Open Throttle)?
Yes
GO to I11.
No
CHECK the APP (Accelerator Pedal Position) sensor and/or PCM. REFER to Computers and Control Systems Information. CHECK the HS-CAN (High Speed Controller Area Network). TEST the system for normal operation.
I11 CHECK 4X4 MODE OPERATION
- Switch the MSS (Mode Select Switch) to 4H mode.
Does the 4X4 mode indicator illuminate correctly?
Yes
GO to I14.
No
GO to I12.
I12 CHECK FOR DTCs
- Shift the transmission into the PARK position.
- Enter the following diagnostic mode on the scan tool: Self-Test- TCCM (Transfer Case Control Module).
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 I13.
I13 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 E. Pinpoint Test E: Four-Wheel Drive (4WD) Does Not Engage At Speed Correctly
No
GO to Pinpoint Test D. Pinpoint Test D: The Vehicle Does Not Shift Between 4X4 AUTO and 4X4 Modes Correctly
I14 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 G. Pinpoint Test G: Straightline Driveline Wind-up
No
GO to I15.
I15 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 I16.
No
GO to Pinpoint Test D. Pinpoint Test D: The Vehicle Does Not Shift Between 4X4 AUTO and 4X4 Modes Correctly
I16 CHECK 4X4 MODE TO 4X2 MODE SHIFT
- With the vehicle at rest, brake applied and transmission in NEUTRAL, switch the MSS (Mode Select Switch) from 4X4 mode to 4X2 mode.
Do the 4WD (Four-Wheel Drive) indicators turn off?
Yes
GO to I19.
No
GO to I17.
I17 CHECK FOR DTCs
- Shift the transmission into the PARK position.
- Enter the following diagnostic mode on the scan tool: Self-Test- TCCM (Transfer Case Control Module).
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 I18.
I18 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 D. Pinpoint Test D: The Vehicle Does Not Shift Between 4X4 AUTO and 4X4 Modes Correctly
No
GO to Pinpoint Test E. Pinpoint Test E: Four-Wheel Drive (4WD) Does Not Engage At Speed Correctly
I19 CHECK FOR TRANSFER CASE DISENGAGEMENT
- With the vehicle in NEUTRAL, position it on a hoist.
- 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 I20.
I20 CHECK FOR LH AND RH IWE (Integrated Wheel End) 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 C. Pinpoint Test C: The Front Axle Does Not Engage/Disengage Correctly
No
GO to I21.
I21 CHECK FOR IWE (Integrated Wheel End) 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 (Integrated Wheel End) apply vacuum circuit.
- Observe the vacuum reading.
Did the vacuum drop more than 25 mm (1 in) Hg per minute?
Yes
CHECK the IWE (Integrated Wheel End) and related components for leaks. GO to Pinpoint Test C. Pinpoint Test C: The Front Axle Does Not Engage/Disengage Correctly
No
GO to I22.
I22 CHECK 4X2 MODE TO 4X4 MODE SHIFT AT SPEED ABOVE 32 KM/H (20 MPH)
- Switch the MSS (Mode Select Switch) to 4X2 mode.
- Drive the vehicle on the road and switch the MSS (Mode Select Switch) 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 (Four-Wheel Drive) system is functioning correctly.
No
GO to Pinpoint Test E. Pinpoint Test E: Four-Wheel Drive (4WD) Does Not Engage At Speed Correctly