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Home >> Mercury >> 2010 >> Milan Base, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 1080 (Four Wheel Drive (4WD) Systems) >> Diagnostic Tests >> Four Wheel Drive (4WD) Systems >> Pinpoint Tests >> Pinpoint Test A: Four Wheel Drive (4WD) System Functional Test >> Pinpoint Test A: Four Wheel Drive (4WD) System Functional Test

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

WARNING: This page is about a different car, the 2008 Mercury Mariner and 2008 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
  1. A1 CHECK FOR WRENCH LIGHT PROVE-OUT 
    • Start the vehicle and observe the wrench light.
    • Does the wrench light illuminate for 3 seconds and then turn OFF? 
    1. YES  : Go to  A2.
    2. NO  : REFER to INSTRUMENT CLUSTER (IC), MESSAGE CENTER, AND WARNING CHIMES article for further diagnosis of the instrument cluster (IC).
  2. A2 CHECK FOR ACTIVE TORQUE COUPLING LOCK 
    • Drive the vehicle on a dry, hard surface in turns while applying the accelerator pedal.
    • Is driveline wind-up present in turns? 
    1. YES  : With the ignition switch in ON position, Key On Engine Off (KOEO), allow the active torque coupling to cool down for at least 10 minutes and REPEAT the test. CHECK for wind-up again. If no wind-up is found, go to  A3 ; if still present, go to Pinpoint Test G .
    2. NO  : Go to  A3.
  3. A3 CHECK FOR VALID THROTTLE POSITION 
    • Enter the following diagnostic mode on the diagnostic tool: PID/DATA Monitor and Record
    • Monitor the throttle position while opening and closing the throttle plate.
    • Does the throttle position match the PID percent value? 
    1. YES  : Go to  A4.
    2. NO  : REFER to the Introduction - Gasoline Engines article.
  4. A4 CHECK FOR CORRECT WHEEL SPEEDS 
    • Monitor the wheel speed PIDs while driving the vehicle at a constant speed of 48 km/h (30 mph).
    • Are all 4 wheel speeds within 2 km/h (1.2 mph) of each other? 
    1. YES  : Go to  A5.
    2. NO  : Go to Pinpoint Test H .
  5. A5 CHECK THE VEHICLE ACCELERATION IN A STRAIGHT LINE 
    • Carry out 3 accelerations from 0-48 km/h (0-30 mph) in a straight line (one each with low, medium and full accelerator pedal application).
    • Does the vehicle pulsate or shudder while accelerating? 
    1. YES  : Go to Pinpoint Test G .
    2. NO  : Go to  A6.
  6. A6 CHECK THE VEHICLE TURNING ABILITY 
    • Drive the vehicle in a fully locked turn, on dry pavement, at 8 km/h (5 mph).
    • Does the vehicle bind in the turn or resist turning? 
    1. YES  : Go to Pinpoint Test G .
    2. NO  : Go to  A7.
  7. A7 CHECK FOR TORQUE AT THE REAR WHEELS 
    • Enter the following diagnostic mode on the scan tool: Active Commands.
    • Command the active torque coupling to a constant 100% applied.
    • Drive the vehicle in a fully locked turn, on dry pavement, at 8 km/h (5 mph).
    • Does the vehicle bind in the turn or resist turning? 
    1. YES  : End the active command. The concern can not be duplicated at this time. RETURN the vehicle to the customer.
    2. NO  : End the active command. CHECK that the driveshaft rotates when the transaxle is in gear. If it does, go to Pinpoint Test F . If it does not, check the PTU. REFER to TRANSFER CASE - POWER TRANSFER UNIT (PTU) article.
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