Pinpoint Test A: Steering Has Lack Of Assist Or Inconsistent Assist - Vehicles with Vacuum Boost

Steering System







Pinpoint Tests


Pinpoint Test A: Steering Has Lack of Assist or Inconsistent Assist - Vehicles with Vacuum Boost

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:
- Steering gear
- Power steering pump
- Power steering hoses



PINPOINT TEST A: STEERING HAS LACK OF ASSIST OR INCONSISTENT ASSIST - VEHICLES WITH VACUUM BOOST

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A1 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 can occur.
- Set the engine at 2,100 rpm and turn the steering wheel fully to the left and right.
- Is steering assist normal with the engine rpm raised?

Yes
INSTALL a new power steering pump.

No
GO to A2.

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A2 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 A3.

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A3 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 A4.

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A4 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 can 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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