Pinpoint Test C: Steering Has Lack Of Assist Or Inconsistent Assist
Steering System
Pinpoint Tests
Pinpoint Test C: 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:
- Contaminated power steering fluid
- Fuel Efficient Power Steering (FEPS) system
- Steering gear
- Power steering pump
- Power steering hoses
PINPOINT TEST C: STEERING HAS LACK OF ASSIST OR INCONSISTENT ASSIST
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C1 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 C2.
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C2 CHECK FOR STEERING EFFORT CONTROL MODULE (SECM) DTCs
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test SECM.
- Retrieve and record any SECM DTCs.
- Are any SECM DTCs present?
Yes
REFER to the Steering Effort Control Module (SECM) DTC Chart. Diagnostic Trouble Code Tests and Associated Procedures
No
GO to C3.
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C3 CHECK THE STEERING RATE SIGNAL (STRSIGU) PID
- Enter the following diagnostic mode on the scan tool: DataLogger SECM.
- Start the engine and monitor the STRSIGU PID while turning the steering wheel right to left.
- Does the PID change as the steering wheel is turned?
Yes
GO to C4.
No
INSTALL a new steering wheel rotation sensor. TEST the system for normal operation.
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C4 CHECK THE STEERING ASSIST WITH THE ENGINE RPM RAISED
- NOTICE: Do not hold the steering wheel at the stops for an extended amount of time. Damage to the power steering pump may occur.
- Set the engine at 2,100 rpm and turn the steering wheel fully to the left and right.
- Is steering assist fully restored to normal with the engine rpm raised?
Yes
INSTALL a new power steering pump.
No
GO to C5.
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C5 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 C6.
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C6 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 C7.
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C7 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.
- Connect the scan tool.
- 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 rpm with the scan tool, 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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