Power Steering System: Diagnosis GMC Acadia I

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(ref-365273-S03182733772010070600000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-365273-S36821411302010070600000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-365273-S42262158172010070600000) provides an overview of each diagnostic category.

Diagnostic Fault Information

Conditions for Running the DTC

1. Ignition ON.
2. Engine OFF test - Initial ignition ON, no engine RPM or vehicle speed present.
3. Engine ON test - If Engine OFF test passes, engine RPM and vehicle speed present.

Conditions for Setting the DTC

A short to voltage, short to ground, or open/high resistance is detected on the high control or low control circuit.

Action Taken When the DTC Sets

1. The ABS and red brake warning indicators illuminate.
2. The driver information center (DIC) displays SERVICE STEERING SYSTEM.
3. The VES system is disabled for the remainder of the ignition cycle.

Conditions for Clearing the DTC

1. A current DTC will clear when the malfunction is no longer present.
2. A history DTC will clear after 100 consecutive ignition cycles with the malfunction no longer present.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the VES actuator.
2. Ignition ON, Command the VES actuator to 100% with a scan tool.
3. Test for B+ between the high control circuit terminal 2 and ground. If not the specified value, test the high control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM.
4. Connect a DMM, set on the diode setting, between the low control circuit terminal 1 and ground.
5. Command the VES actuator to 0% with a scan tool. The DMM reading should be greater than 2.5 volts or display O.L. If less than the specified value, test the low control circuit for a short to voltage or a short to ground. If the circuit tests normal, replace the EBCM.
6. Command the VES actuator to 100% with a scan tool. The DMM reading should be less than 1 volt. If greater than the specified range, test the low control circuit for an open/high resistance. If the circuit tests normal, replace the EBCM.
7. If all circuits test normal, test or replace the VES actuator.

Component Testing

1. Ignition OFF, disconnect the harness connector at the VES actuator.
2. Test for 5-10 ohms between the control terminals 1 and 2. If not within the specified range, replace the VES actuator.
3. Test for infinite resistance between each terminal and the VES actuator housing/case. If not the specified value, replace the VES actuator.

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the power steering system.
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
3. Inspect for leaking power steering components. If necessary, refer to «Power Steering Fluid Leaks»(ref-365269-S20134928622010070600000) .
4. Verify the power steering reservoir for the proper operating specification. Refer to «Checking and Adding Power Steering Fluid»(ref-365269-S23312474372010070600000) .
5. Inspect the power steering fluid for the following indications of contamination: Milky fluid - water Brown fluid - burnt Debris in fluid - plastic or dirt
6. If necessary, flush the power steering system. Refer to «Power Steering System Flushing»(ref-365269-S29715384062010070600000) .

Symptoms List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «Power Steering Fluid Leaks»(ref-365269-S20134928622010070600000)
2. «Rattle, Clunk, or Shudder Noise from the Power Steering System»(ref-365269-S32983407922010070600000)
3. «Whine or Growl Noise from the Power Steering System»(ref-365269-S05423795472010070600000)
4. «Steering Effort Hard in One or Both Directions»(ref-365269-S19050282952010070600000)
5. «Steering Effort Too Easy in One or Both Directions»(ref-365269-S26561414722010070600000)

Scheme 3

Inspection Procedure

1. Turn the ignition key to the ON position with the engine OFF.
2. With the aid of an assistant, turn the steering wheel to the full stop position and hold the steering wheel in that position until the test is complete. The tie rod being tested should be inside the steering gear housing seated against the steering stop.
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-365243-S07204316382010070600000) .
4. If there is not a good location for the J-8001: Dial Indicator pointer at the steering gear housing, install a large worm gear hose clamp to the steering gear housing over the larger steering gear boot clamp and align the clamp so that the screw can be a location for the J-8001: Dial Indicator pointer.
5. Install the J-8001: Dial Indicator between the inner tie rod (2) and the steering gear housing or the worm gear clamp in such a way as to measure the lash between the inner tie rod and the steering gear housing.
6. Grasping the tire at the 3 o'clock (2) and 9 o'clock (1) positions, gently push in on one side of the tire in order to remove any lash.
7. Zero the J-8001: Dial Indicator.
8. On the same side of the tire previously pushed in, gently pull out and measure the lash.
9. Record the measurement seen on the J-8001: Dial Indicator.
10. If the measured value exceeds 0.5 mm (0.02 in), replace the inner tie rod. Refer to «Steering Linkage Inner Tie Rod Replacement»(ref-365269-S38619216612010070600000) .
11. Repeat the procedure for the other side.

1. Inspect the outer tie rod end seal. If the outer tie rod end seal is torn, replace the outer tie rod end. Refer to «Steering Linkage Outer Tie Rod Replacement»(ref-365269-S28617561452010070600000) .
2. Raise the side of the vehicle being inspected with a floor jack while maintaining contact between the opposite wheel and the shop floor. Support the lower control arm with a floor jack stand as far outboard as possible and remove the floor jack. Refer to «Lifting and Jacking the Vehicle»(ref-365243-S07204316382010070600000) .
3. Install the J-8001: Dial Indicator between the outer tie rod end and the steering knuckle as shown in the graphic. Note that the tire and wheel assembly is shown removed only for clarification of the J-8001: Dial Indicator position.
4. Grasping the tire at the 3 o'clock (2) and 9 o'clock (1) positions, gently push in on one side of the tire to remove any lash.
5. Zero the J-8001: Dial Indicator.
6. On the same side of the tire previously pushed inwards, gently pull outwards and measure the lash.
7. Record the measurement seen on the J-8001: Dial Indicator.
8. If the measured value exceeds 0.5 mm (0.02 in) then replace the outer tie rod. Refer to «Steering Linkage Outer Tie Rod Replacement»(ref-365269-S28617561452010070600000) .
9. Repeat the procedure for the other side.

1. With the engine OFF, fill the pump reservoir to the MAX mark on capstick fluid level indicator.
2. Raise the vehicle until the front wheels are off the ground. Refer to «Lifting and Jacking the Vehicle»(ref-365243-S07204316382010070600000) .
3. Start the engine and turn the steering wheel from stop to stop 4 times.
4. Verify power steering fluid level. Refer to «Checking and Adding Power Steering Fluid»(ref-365269-S23312474372010070600000) .
5. Rotate steering wheel from left to right another 8 times. Check for signs of cavitation or fluid aeration (pump noise/whining).
6. Verify the fluid level. Repeat the bleed procedure, if necessary.