Pinpoint Test A: Steering Has Lack of Assist or Inconsistent Assist
Steering System
Pinpoint Test A: Steering Has Lack of Assist or Inconsistent Assist
NOTE: Hard steering or lack of assist is experienced when the steering wheel effort exceeds specifications. Hard steering can remain constant through the full turn, occur near the end of a turn or differ right to left. It is important to know the difference between hard steering/lack of assist and poor returnability/sticky steering.
This pinpoint test is intended to diagnose the following:
- Power steering fluid contamination
- Steering gear
- Power steering pump
- Power steering hoses
PINPOINT TEST A: STEERING HAS LACK OF ASSIST OR INCONSISTENT ASSIST
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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 Power Steering System Flushing.
No
GO to A2.
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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.
- NOTICE: Do not hold the steering wheel at the stops for an extended amount of time. Damage to the power steering pump may occur.
- 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.
- Is the steering assist normal with the engine rpm raised?
Yes
INSTALL a new power steering pump.
No
TOGGLE the active command OFF. GO to A3.
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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.
No
GO to A4.
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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.
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A5 MONITOR THE ENGINE RPM CHANGES
NOTICE: 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.
No
INSTALL a new power steering pump.
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