Pinpoint Test N: The Vehicle Binds In Turns/Resists Turning/Pulsates/Shudders In A Straight Line
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:
4WD HIGH/LOW (4H/4L) is not intended for driving on hard/dry surfaces.
- N1 VERIFY THE CONCERN
- Test drive the vehicle on a straight stretch of road in 4WD AUTO mode.
- Drive the vehicle through turns and parking lot maneuvers.
- Does the vehicle bind, pulsate or shudder?
- Yes : If the problem occurs in A4WD mode, GO to N2; in 4WD HIGH mode or 4WD LOW mode, binding is a normal condition.
- No : GO to PINPOINT TEST L .
- N2 CHECK THE 4WD INDICATORS
- Review the test drive notes.
- Did any of the instrument cluster 4WD indicators illuminate or flash?
- N3 VERIFY THE FAULT
- Review the test drive notes.
- Was 4WD HIGH or 4WD LOW selected when the 4x4 indicators were illuminated?
- Yes : The system is functioning correctly.
- No : The fault may have been caused by an intermittent, uncommanded or autolock shift. TEST the system for normal operation. GO to PINPOINT TEST L .
- N4 CHECK FOR DTCs
- Connect the diagnostic tool.
- Carry out the on-demand self test.
- Are DTCs retrieved?
- Yes : REFER to the 4WD MODULE DTC INDEX diagnosis.
- No : GO to N5.
- N5 VERIFY THE CONCERN
- Disconnect: Transfer Case C350.
- Test drive the vehicle on a straight stretch of road and in turns, and shift the transfer case through each mode. Record any fault conditions.
- Is the concern present?
- Yes
: Vehicles with limited slip rear differential:
The condition may be normal and no repair action is necessary. CHECK the rear axle to verify. REFER to REAR DRIVE AXLE/DIFFERENTIAL - FORD 8.8-INCH RING GEAR
.
Vehicles without limited slip rear differential: INSPECT the driveline components for damage or wear. REFER to INSPECTION AND VERIFICATION .
- No : GO to N6.
- N6 CHECK THE TRANSFER CASE CLUTCH DUTY CYCLE PID
- Connect: Transfer Case C350.
- CLEAR the DTCs.
- 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 at closed throttle, engine off, key on.
- Is the clutch duty cycle greater than 10%?
- Yes : GO to N7.
- No : CHECK the transfer case. REFER to TRANSFER CASE - ELECTRONIC SHIFT .
- N7 CHECK THE 4WD SHAFT SPEED PIDs
- Enter the following diagnostic mode on the diagnostic tool: PID/DATA Monitor and Record.
- While driving the vehicle at 30 km/h (18 mph), monitor the shaft speed PIDs.
- Compare the speedometer reading to the wheel speed PIDs.
- Do the wheel speed PIDs and speedometer speeds match within 1.5 km/h (1 mph)?
- Yes : GO to N8.
- No : VERIFY that the 4 road wheels are the same size and have similar tread depth. CHECK the ABS system for faults. REFER to ANTI-LOCK CONTROL .
- N8 CHECK THE 4WD THROTTLE POSITION PID
- Enter the following diagnostic mode on the diagnostic tool: PID/DATA Monitor and Record.
- Slowly move throttle from closed throttle to WOT and observe the 4WD throttle position PID.
- Does the value vary between 0% at closed throttle and 100% at WOT?
- Yes : GO to N9.
- No : CHECK the throttle position sensor and/or PCM for faults. See INTRODUCTION - GASOLINE article.
- N9 CHECK THE TRANSFER CASE FRONT DRIVESHAFT OUTPUT
- Raise the vehicle on a hoist. Refer to JACKING AND LIFTING .
- Rotate the front driveshaft by hand.
- Does the front driveshaft rotate freely (does it require less than 45 Nm [33 lb-ft] to rotate)?
- Yes : INSTALL a new 4WD module. REFER to FUEL CHARGING AND CONTROLS - 4.0L SOHC or FUEL CHARGING AND CONTROLS - 4.6L (2V) . REPEAT the self test. TEST the system for normal operation.
- No : CHECK the transfer case. REFER to TRANSFER CASE - ELECTRONIC SHIFT . TEST the system for normal operation.