Pinpoint Test Z: Electronic Shift-On-The-Fly (ESOF) Functional Test
Four Wheel Drive (4WD) Systems - Electronic Shift
Pinpoint Tests
Pinpoint Test Z: Electronic Shift-On-The-Fly (ESOF) Functional Test
Normal Operation
When operating in 4H or 4L mode, the transfer case and both Integrated Wheel Ends (IWEs) are locked. When in 4L mode, the transfer case low range gear set provides an additional 2.64 gear reduction. When operating in 2H mode, the transfer case and both IWEs are unlocked.
This pinpoint test is intended to diagnose the following:
- 4WD system and/or related components
PINPOINT TEST Z: ESOF FUNCTIONAL TEST
WARNING: When directed to drive the vehicle as part of this test, drive the vehicle on a hard surface in an area without traffic to prevent a crash. Failure to follow these instructions may result in personal injury.
NOTE: 4X4 high/low (4H/4L) is not intended for driving on hard/dry surfaces.
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Z1 CHECK FOR IPC DTCs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - IPC.
- Are any DTCs present?
Yes
If DTC U0102:00 is retrieved, REFER to Module Communications Network Testing and Inspection to diagnose lost communication with Transfer Case Control Module (TCCM). For all other DTCs, REFER to Instrumentation, Message Center, and Warning Chimes Testing and Inspection.
No
GO to Z2.
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Z2 CHECK 2H OPERATION
- Switch the Mode Select Switch (MSS) to 2H while monitoring the message center.
- Does the message center display 4X2 for approximately 4 seconds?
Yes
GO to Z5.
No
GO to Z3.
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Z3 CHECK FOR DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - TCCM.
- Are any DTCs present?
Yes
REFER to the Transfer Case Control Module (TCCM) DTC Chart for diagnosis. Four Wheel Drive (4WD) Systems - Electronic Shift
No
GO to Z4.
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Z4 CHECK FOR WIND-UP IN 2H
- Drive the vehicle on a dry, hard surface while executing turns.
- Is wind-up present in turns?
Yes
GO to Pinpoint Test S. Pinpoint Test S: The Vehicle Does Not Shift Between 2H and 4H Correctly and/or Grinding Noise Heard During Four-Wheel Drive (4W
No
GO to Z5.
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Z5 CHECK 4H OPERATION
- Switch the MSS to 4H while monitoring the message center.
- Does the message center display 4X4 HIGH?
Yes
GO to Z8.
No
GO to Z6.
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Z6 CHECK FOR DTCs
- Transmission in PARK.
- Enter the following diagnostic mode on the scan tool: Self Test - TCCM.
- Are any DTCs present?
Yes
REFER to the Transfer Case Control Module (TCCM) DTC Chart for diagnosis. Four Wheel Drive (4WD) Systems - Electronic Shift
No
GO to Z7.
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Z7 CHECK FOR WIND-UP IN 4H
- Drive the vehicle on a dry, hard surface while executing turns.
- Is wind-up present in turns?
Yes
GO to Pinpoint Test K. Pinpoint Test K: DTC P1832:00
No
GO to Pinpoint Test L. Pinpoint Test L: DTC P1833:00
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Z8 CHECK FOR STRAIGHT LINE 4H WIND-UP
- Drive the vehicle on a dry, hard surface.
- Is straightline wind-up present?
Yes
GO to Pinpoint Test Y. Pinpoint Test Y: Vehicle Pulsates or Shudders in a Straight Line (Straightline Driveline Wind-up)
No
GO to Z9.
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Z9 CHECK 4H WIND-UP IN TURNS
- Drive the vehicle in 4H while turning.
- Is wind-up present in turns?
Yes
GO to Z10.
No
GO to Pinpoint Test S. Pinpoint Test S: The Vehicle Does Not Shift Between 2H and 4H Correctly and/or Grinding Noise Heard During Four-Wheel Drive (4W
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Z10 CHECK 4L OPERATION
- Bring the vehicle to a stop with the transmission in NEUTRAL and switch the MSS to 4L.
- Does the 4X4 LOW indicator illuminate correctly?
Yes
GO to Z13.
No
GO to Z11.
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Z11 CHECK FOR DTCs
- Transmission in PARK.
- Enter the following diagnostic mode on the scan tool: Self Test - TCCM.
- Are any DTCs present?
Yes
REFER to the Transfer Case Control Module (TCCM) DTC Chart for diagnosis. Four Wheel Drive (4WD) Systems - Electronic Shift
No
GO to Z12.
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Z12 CHECK FOR WIND-UP IN 4L
- Drive the vehicle on a dry, hard surface while executing turns.
- Is wind-up present in turns?
Yes
GO to Pinpoint Test R. Pinpoint Test R: The Four-Wheel Drive (4WD) Indicators Do Not Operate Correctly
No
GO to Pinpoint Test T. Pinpoint Test T: The Vehicle Does Not Shift Between 4H and 4L Modes Correctly
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Z13 CHECK FOR 4L WIND-UP IN TURNS
- Drive the vehicle on a dry, hard surface while executing turns.
- Is wind-up present and 4L functioning?
Yes
GO to Z14.
No
CHECK for TCCM DTCs. REFER to the Inspection and Verification procedure. If no DTCs are present, GO to Pinpoint Test T. Inspection and Verification Pinpoint Test T: The Vehicle Does Not Shift Between 4H and 4L Modes Correctly
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Z14 CHECK 4L TO 2H SHIFT
- With the vehicle at a stop and transmission in NEUTRAL, switch the MSS from 4L to 2H.
- Does the message center display 4X2 for approximately 4 seconds?
Yes
GO to Z17.
No
GO to Z15.
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Z15 CHECK FOR DTCs
- Transmission in PARK.
- Enter the following diagnostic mode on the scan tool: Self Test - TCCM.
- Are any DTCs present?
Yes
REFER to the Transfer Case Control Module (TCCM) DTC Chart for diagnosis. Four Wheel Drive (4WD) Systems - Electronic Shift
No
GO to Z16.
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Z16 CHECK FOR WIND-UP IN 2H
- Switch the MSS to 2H.
- Drive the vehicle on a dry, hard surface while executing turns.
- Is wind-up present in turns?
Yes
GO to Pinpoint Test T. Pinpoint Test T: The Vehicle Does Not Shift Between 4H and 4L Modes Correctly
No
GO to Pinpoint Test R. Pinpoint Test R: The Four-Wheel Drive (4WD) Indicators Do Not Operate Correctly
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Z17 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
REFER to Transfer Case.
No
GO to Z18.
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Z18 CHECK FOR LH AND RH IWE DISENGAGEMENT
NOTE: The engine must be idling during the following steps to supply the vacuum required for the IWEs to engage and disengage.
- Start the engine.
- Rotate the LH front tire one revolution forward and one revolution backward while observing the LH front halfshaft and U-joint.
- Rotate the RH front tire one revolution forward and one revolution backward while observing the RH front halfshaft and U-joint.
- Does the LH or RH front halfshaft rotate?
Yes
GO to Pinpoint Test U. Pinpoint Test U: The Front Axle Does Not Engage/Disengage Correctly
No
GO to Z19.
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Z19 CHECK FOR IWE VACUUM LEAKS
- Ignition OFF.
- Disconnect both vacuum lines from the IWE solenoid.
- Using a 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 U. Pinpoint Test U: The Front Axle Does Not Engage/Disengage Correctly
No
GO to Z20.
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Z20 CHECK 2H TO 4H SHIFT AT SPEED ABOVE 32 KM/H (20 MPH)
- Switch the MSS to 2H.
- Drive the vehicle on the road and shift from 2H to 4H while driving above 32 km/h (20 mph).
- Does the transfer case shift to 4H satisfactorily?
Yes
The Four-Wheel Drive (4WD) system is functioning correctly.
No
GO to Pinpoint Test X. Pinpoint Test X: The Four-Wheel Drive (4WD) Does Not Engage at Speed Correctly
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