April 5, 2026: LEMON Manuals is launched! Read the announcement.

Pinpoint Test A : Four-Wheel Drive (4WD) System Functional Test

A1 CHECK MODULES FOR ON DEMAND DTCS
- Ignition ON.
- Gear Selector in Park.
- Enter the following diagnostic mode: TCCM KOEO Self-test, Enter the following diagnostic mode: ATCM KOEO Self-test.
Are DTCs retrieved?

Yes REFER to DTC Chart: TCCM . REFER to DTC Chart: All-Terrain Control Module .

No GO to A2

A2 CHECK ROTARY SWITCH
- Gear Selector in Park
- Start Engine.
- Enter the Diagnostic Mode: Datalogger ATCM.
- Monitor the PIDs LAST_DIR_CLCK_RT and LAST_DIR_CNTR_LEFT while rotating the 4x4 Switch Module knob clockwise and counterclockwise.
Do the PIDs update correctly indicating the last direction the rotary knob was rotated?

Yes GO to A3

No INSTALL a new ATCM. REFER to: Mode Select Switch (MSS) .

A3 CHECK SWITCH INPUT TO THE TCCM IN 2H
- NORMAL drive Mode.
- Gear Selector in Park.
- Engine running.
- Enter the Diagnostic Mode: Datalogger TCCM.
- Monitor the PID 4x4_SW.
Does the 4x4_SW display Two Wheel Drive?

Yes The TCCM recognizes a valid input from the ATCM. GO to A4

No Perform Pinpoint test for no ATCM communication. REFER to: Communications Network .

A4 CHECK THE IWE DISENGAGEMENT

NOTE: The TCCM may command the IWEs to engage during 2H operation to warm up the front axle.
- With the vehicle in NEUTRAL, position it on a hoist. Raise the vehicle until all 4 wheels are off the ground. REFER to: Jacking and Lifting .
- Engine Running
  - The engine must be idling during the following steps to supply the vacuum required for the IWE's to disengage.
- Gear selector in Neutral.
- NORMAL drive Mode.
- Enter the following diagnostic mode: Datalogger TCCM
- Command IWE_OUT_ENGAGED # to No (False)
- Rotate the RH front tire one revolution forward and one revolution backward while observing the RH front halfshaft.
- Rotate the RH front tire one revolution forward and one revolution backward while observing the RH front halfshaft.
Did both front halfshafts remain stationary?

Yes End Output State Control. GO to A5

No End Output State Control. GO to Pinpoint Test E .

A5 CHECK THE IWE ENGAGEMENT
- Vehicle on hoist with all 4 wheels off the ground.
- Engine running.
- Gear selector in Neutral.
- DEEP CONDITIONS drive mode.
- Rotate the LH front tire one revolution forward and one revolution backward while observing the LH front halfshaft.
- Rotate the RH front tire one revolution forward and one revolution backward while observing the RH front halfshaft
Did both front halfshafts rotate?

Yes The front axle is operating properly at this time. GO to A6

No GO to Pinpoint Test E

A6 CHECK TORQUE ON DEMAND CLUTCH OPERATION

DEEP CONDITIONS drive mode.

Drive the vehicle on a dry, hard surface while full lock turns.

Is wind-up / vehicle bind present?

Yes	The TOD clutch is transmitting torque as expected GO to A7

No	The TOD clutch is slipping / not transferring torque. CHECK the transfer case. REFER to: Transfer Case - Vehicles With: 1-Speed Torque On Demand Transfer Case .

A7 CHECK FOR WIND-UP IN 2H MODE WITH IWES ENGAGED

NORMAL drive Mode.

Enter the following diagnostic mode: datalogger TCCM.

Command IWE_OUT_ENGAGED # to Yes (True)

Drive the vehicle on a dry, hard surface while full lock turns.

Is wind-up / vehicle bind present?

Yes	Exit Output State Control. The transfer case is unable to disengage 4x4. REFER to: Transfer Case - Vehicles With: 1-Speed Torque On Demand Transfer Case .

No	Exit Output State Control. The 4WD system is operating as designed.