Pinpoint Test A: Steering Has Lack Of Assist Or Inconsistent Assist
WARNING: This page is about a different car, the 2010 Mercury Milan, 2010 Lincoln MKZ, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
- A1 CHECK FOR FLUID CONTAMINATION
- Check the power steering fluid for contamination.
- Is there any fluid contamination?
- Yes: FLUSH the power steering system as necessary. REFER to POWER STEERING SYSTEM FLUSHING .
- No: GO to A2.
- A2 CHECK THE STEERING ASSIST WITH THE ENGINE RPM RAISED
- Connect the scan tool.
- Enter the following diagnostic mode on the scan tool: DataLogger - PCM.
- Using the engine revolutions per minute (RPM) active command, set the engine at 2,100 rpm and then turn the steering wheel fully to the left and right.NOTE: Do not hold the steering wheel at the stops for an extended amount of time. Damage to the power steering pump may occur.
- Is the steering assist normal with the engine rpm raised?
- Yes: INSTALL a new power steering pump. REFER to REMOVAL AND INSTALLATION .
- No: TOGGLE the active command OFF. GO to A3.
- A3 CHECK FOR A CHANGE OF ASSIST ON LEFT AND RIGHT TURNS
- With the engine at idle, turn the steering wheel fully to the left and to the right.
- Does the steering assist change when turning from right to left?
- Yes: INSTALL a new steering gear. REFER to POWER STEERING .
- No: GO to A4.
- A4 CHECK THE STEERING LINES AND HOSES FOR RESTRICTIONS
- Inspect the steering lines and hoses for damage, kinks or restrictions.
- Are the steering lines or hoses damaged, kinked or restricted?
- Yes: INSTALL new lines or hoses as necessary.
- No: GO to A5.
- A5 MONITOR THE ENGINE RPM CHANGES NOTE: Do not hold the steering wheel at the stops for an extended amount of time. Damage to the power steering pump may occur.NOTE: Make sure that the vehicle is on a flat, dry surface, all accessories are in the OFF position and that the steering system is at normal operating temperature.
- Enter the following diagnostic mode on the scan tool: DataLogger - PCM.
- Start the engine.
- With the engine at idle, raise the power steering fluid temperature to 74-80°C (165-176°F) by rotating the steering wheel fully to the left and right several times.
- While monitoring the engine revolutions per minute (RPM) PID, turn the steering wheel quickly to the left stop position and then to the right stop position.
- Note the engine rpm during the turns.
- Does the engine rpm change (even temporarily) more than 30 rpm when turning the steering wheel?
- Yes: INSTALL a new steering gear. REFER to POWER STEERING .
- No: INSTALL a new power steering pump. REFER to REMOVAL AND INSTALLATION .