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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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