Pinpoint Test L: 4WD System Functional Test
WARNING: This page is about a different car, the 2005 Mercury Mountaineer and 2005 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
4H and 4L modes are not intended for driving on hard/dry surfaces.
- L1 CHECK 4WD INDICATOR PROVE-OUT
- Key in ON position.
- Do the 4WD indicators illuminate at prove out?
- Yes : GO to L2.
- No : CHECK the instrument cluster. REFER to INSTRUMENT CLUSTER AND PANEL ILLUMINATION .
- L2 CHECK 4WD AUTO OPERATION
- If in 4L, switch the MSS to 4WD AUTO.
- Are the 4WD indicators off?
- Yes : GO to L5.
- No : GO to L3.
- L3 CHECK FOR DTCs
- Connect the diagnostic tool.
- Carry out the on-demand self test.
- Are DTCS present?
- Yes : REFER to the 4WD CONTROL MODULE (PCM) DTC INDEX for diagnosis.
- No : GO to L4.
- L4 CHECK FOR WIND-UP IN 4WD AUTO
- Drive the vehicle on a dry, hard surface in turns.
- Is wind-up present in turns?
- Yes : If 4L indicator is on, GO to PINPOINT TEST K . If the 4H indicator is on, GO to PINPOINT TEST H .
- No : GO to PINPOINT TEST I .
- L5 CHECK THE TRANSFER CASE CLUTCH DUTY CYCLE PID
- Enter the following diagnostic mode on the diagnostic tool: PID/DATA Monitor and Record.
- Monitor the transfer case clutch duty cycle (pulse width modulated-[PWM]) PID.
- Does the PID indicate 2 to 4% clutch application at closed throttle?
- Yes : GO to L7.
- No : GO to L6.
- L6 CHECK THE CONTACT PLATE ENCODER PIDs
- Enter the following diagnostic mode on the diagnostic tool: PID/DATA Monitor and Record.
- Monitor the contact plate position PIDs. Refer to the following CHART :CONTACT PLATE POSITION PID SPECIFICATION
Contact Plate Position PID MSS PID 4WD AUTO/4H MSS PID 4L PLATE___A CLOSED OPEN PLATE___B OPEN CLOSED PLATE___C CLOSED OPEN PLATE___D CLOSED CLOSED - Does the contact plate position PID indicate that the shift motor is in 4WD Auto?
- Yes : GO to PINPOINT TEST H .
- No : GO to PINPOINT TEST K .
- L7 CHECK SHAFT SPEED PIDs
- Enter the following diagnostic mode on the diagnostic tool: PID/DATA Monitor and Record.
- Monitor the transfer case front and rear shaft speeds.
- Drive the vehicle 30 km/h (18 mph).
- Record and compare the front wheel speed and the rear wheel speed.
- Do the front shaft speed and rear shaft speed values match within 1.5 km/h (1 mph)?
- Yes : GO to L8.
- No : CHECK the ABS system. REFER to ANTI-LOCK CONTROL and VERIFY that the four road tire sizes match.
- L8 CHECK THE THROTTLE POSITION PID
- Enter the following diagnostic mode on the diagnostic tool: PID/DATA Monitor and Record.
- Monitor the throttle position PID from the 4x4 module.
- Key ON, engine OFF.
- Slowly move throttle from closed throttle to WOT and observe the 4WD module throttle sensor PID.
- Does the PID value vary between 0% at closed throttle and 100% at WOT?
- Yes : GO to L9.
- No : CHECK the throttle position sensor and/or PCM. See INTRODUCTION - GASOLINE article.
- L9 CHECK FOR WIND-UP IN TURNS ON THROTTLE
- Drive the vehicle on a dry, hard surface, executing turns while applying the throttle.
- Is wind-up present?
- Yes : CHECK the transfer case. REFER to TRANSFER CASE - ELECTRONIC SHIFT .
- No : GO to L10.
- L10 CHECK 4H OPERATION
- Select 4H.
- Does the 4H indicator illuminate correctly?
- Yes : GO to L11.
- No : GO to L12.
- L11 CHECK FOR 4H WIND-UP
- Drive the vehicle on a dry, hard surface in turns.
- Is wind-up present in turns?
- Yes : GO to L14.
- No : GO to PINPOINT TEST H .
- L12 CHECK FOR DTCs
- Connect the diagnostic tool.
- Carry out the on-demand self test.
- Are DTCS present?
- Yes : REFER to the 4WD CONTROL MODULE (PCM) DTC INDEX for diagnosis.
- No : GO to L13.
- L13 CHECK FOR WIND-UP IN 4H ON THROTTLE
- Drive the vehicle on a dry, hard surface in turns while applying the throttle.
- Is wind-up present in turns?
- Yes : GO to PINPOINT TEST I .
- No : GO to PINPOINT TEST H .
- L14 CHECK 4L OPERATION
- Select 4L:
- Vehicle stationary.
- Press the brake.
- Shift the transmission to N (NEUTRAL).
- Select 4L.
- Wait for the 4WD LOW indicator to illuminate in the instrument cluster indicating that the shift is complete.
- Does the 4L indicator illuminate?
- Yes : GO to L15.
- No : GO to L16.
- Select 4L:
- L15 CHECK FOR WIND-UP IN 4L MODE
- Drive the vehicle on a dry, hard surface in turns while applying the throttle.
- Is wind-up present in turns?
- L16 CHECK FOR DTCs
- Connect the diagnostic tool.
- Carry out the on-demand self test.
- Are DTCS present?
- Yes : REFER to the 4WD CONTROL MODULE (PCM) DTC INDEX for diagnosis.
- No : GO to L18.
- L17 CHECK FOR DTCs
- Connect the diagnostic tool.
- Carry out the on-demand self test.
- Are DTCs present?
- Yes : REFER to the 4WD CONTROL MODULE (PCM) DTC INDEX for diagnosis.
- No : GO to PINPOINT TEST K .
- L18 CHECK FOR WIND-UP IN 4L MODE
- Drive the vehicle on a dry, hard surface in turns while applying the throttle.
- Is wind-up present in turns?
- Yes : GO to PINPOINT TEST H .
- No : GO to PINPOINT TEST K .
- L19 CHECK 4WD AUTO OPERATION
- Switch the MSS to 4WD AUTO.
- Do the 4WD indicators turn off?
- Yes : The 4WD system is operating correctly.
- No : GO to L20.
- L20 CHECK FOR DTCs
- Carry out the on-demand self test.
- Are DTCs retrieved?
- Yes : REFER the 4WD Control Module (PCM) DTC Index.
- No : GO to L21.
- L21 CHECK FOR WIND-UP IN 4WD AUTO
- Drive the vehicle on a dry, hard surface in turns.
- Is wind-up present in turns?
- Yes : GO to PINPOINT TEST I .
- No : GO to PINPOINT TEST K .