Component Tests and General Diagnostics
Steering System
Component Tests
Power Steering Fluid Leak Test
NOTE: This test should only be carried out if a leak in the system has not been detected during a thorough visual inspection. Refer to Inspection and Verification. Inspection and Verification
1. Remove the power steering pump reservoir cap and check the power steering fluid level. If necessary, add the specified power steering fluid.
2. Tightly install the Power Steering Evacuation Cap onto the reservoir and connect the Vacuum Pump Kit to the Evacuation Cap.
3. Using the Vacuum Pump Kit, apply 68-85 kPa (20-25 in-Hg) of vacuum to the power steering system.
4. Observe the vacuum gauge for 30 seconds. If the vacuum gauge reading drops more than 3 kPa (0.88 in-Hg), a leak is present.
5. Remove the Vacuum Pump Kit.
6. Start the engine and insert the Dial Thermometer into the Evacuation Cap.
7. NOTICE: Do not hold the steering wheel at the stops for an extended amount of time. Damage to the power steering pump may occur.
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.
8. Stop the engine and visually inspect the system for leaks.
- If a leak is evident, repair as necessary.
- If a leak is not evident, add the specified UV fluorescent tracer dye to the power steering fluid. Use 14.78 ml (1/2 oz) of dye solution for every 1.89L (2 qt) of power steering fluid.
9. Start the engine.
10. NOTICE: Do not hold the steering wheel at the stops for an extended amount of time. Damage to the power steering pump may occur.
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.
11. Stop the engine and inspect the system for traces of UV dye using the 100W/12 Volt DC UV Lamp. Repair as necessary.
Power Steering Pressure Test
1. Place a Dial Thermometer in the power steering fluid reservoir.
2. Install the scan tool and monitor the power steering pressure switch (PSP_V) PID.
3. NOTICE: Do not hold the steering wheel against the stops for an extended amount of time. Damage to the power steering pump can occur.
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.
4. With the steering wheel in the straight-ahead position and the engine speed at idle, record the pressure reading.
- If the pressure reading is not within specification, check the power steering lines/hoses for kinks and restrictions and repair as necessary. Refer to General Specifications.
5. NOTICE: Do not hold the steering wheel against the stops for an extended amount of time. Damage to the power steering pump can occur.
Turn (or have an assistant turn) the steering wheel to the left and right stops. Record pressure readings at the stops.
- The pressure reading at both stops should be nearly the same as the maximum pump relief pressure (1,300-1,480 psi).
- If the pressure reaches the maximum pump relief pressure (1,300-1,480 psi) AT ONE STOP BUT NOT THE OTHER, install a new steering gear. Refer to Power Steering Steering Gear.
- If the pressure does not reach the maximum pump relief pressure (1,300-1,480 psi) AT ALL, install a new power steering pump. Refer to Power Steering Power Steering Pump.
Steering Gear Valve Test
1. With the vehicle in NEUTRAL, position it on a hoist. Refer to Jacking and Lifting Service and Repair.
- Raise the vehicle until the front wheels are off the ground.
2. NOTE: Do not hold the steering wheel while carrying-out this step.
Start the engine.
- If the steering wheel rotates in either direction (with no hand input), install a new steering gear. Refer to Power Steering Steering Gear.
Steering Gear Grunt/Shudder Test
1. Start and run the vehicle to operating temperature.
2. Set engine idle speed to 1,200 rpm.
3. NOTICE: Do not hold the steering wheel against the stops for an extended amount of time. Damage to the power steering pump may occur.
Rotate the steering wheel to the RH stop, then turn the steering wheel 90 degrees back from that position. Slowly turn the steering wheel back and forth approximately one-twelfth of a full turn.
4. Turn the steering wheel another 90 degrees. Slowly turn the steering wheel back and forth approximately one-twelfth of a full turn.
5. Repeat the test with the power steering fluid at different temperatures.
6. If a light grunt is heard or a low (50-200 Hz) shudder is present, this is a normal steering system condition.
7. If a loud grunt is heard, or a strong shudder is felt, purge the power steering system. Refer to Power Steering System Purging Power Steering System Purging. If a loud grunt or strong shudder still exists, check the power steering lines/hoses for restrictions or damage and repair as necessary. Refer to Power Steering Testing and Inspection. If the lines/hoses are OK, install a new steering gear. Refer to Power Steering Steering Gear.
Steering Linkage Test
1. With the vehicle in NEUTRAL, position it on a hoist. Refer to Jacking and Lifting Service and Repair.
2. Using hand force only, check the inner and outer tie rods for vertical and lateral movement in the tie-rod ball studs/sockets.
- If there is any lateral or vertical movement in the tie-rod ball studs/sockets (inner or outer), a new tie rod must be installed. Refer to Steering Linkage Service and Repair.